Can nitrogen amendment increase soil carbon storage? SETH ADAMS*, SUE J. GRAYSTON Belowground Ecosystem Group, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 [email protected] Keywords: nitrogen cycling, carbon sequestration, fertilization, enzymes Canada’s forest companies have expressed considerable interest in forest fertilization as a method for increasing tree growth and shortening rotation times. Additionally, nitrogen (N)-amendment may also increase soil carbon (C) sequestration due to suppression of the enzymes that decompose recalcitrant (e.g. high lignin) forest litter (Berg and Matzner, 1997). As part of a larger study assessing N fertilization effects on forest productivity (eddy covariance), C stocks and N2O emissions I am determining soil enzyme activities following N fertilization. I am also studying N mineralization and nitrification following fertilization to understand the processes which may lead to N2O emissions. Denitrification rates are determined using in-situ soil bag incubations which are analyzed for beforeand-after NH4+ and NO3- concentrations, enzyme activities are measured using colorimetric and fluorimetric assays and denitrification potential is measured with a sealed-jar experiment using a gas chromatograph. Studies are on-going, I hypothesize that urea will quickly mineralize to NH4+, N-amendment will increase nitrification and denitrification and N-amendment will decrease ligninolytic enzyme activity. Microbial biomass N will be much higher in the N-amended samples than control, supporting the assumption that the easily-consumed labile N is replacing the need for enzymatic “N-mining” (Craine et al., 2007). Reduced enzyme activity can result in lower decomposition of recalcitrant litter, leading to an increase in soil C storage. Denitrification potential will increase, possibly resulting in the release of additional N2O. Reference List Craine, J.M., C.M. Morrow, N. Fierer. 2007. Microbial nitrogen limitation increases decomposition. Ecology. 88(8): 2105-2113. Berg, B. and E. Matzner. 1997. Effect of N deposition on decomposition of plant litter and soil organic matter in forest systems. Environ. Rev. 5: 1-25

Comparative effectiveness of auxin and l-tryptophan blended compost for improving growth and yield of maize RIZWAN AHMAD1, M. ARSHAD2, AZEEM KHALID2, M. ASLAM1, S.N. KHOKHAR1AND M. NAVEED2 1

Land Resources Research Program, National Agriculture Research Centre , Islamabad-54400, Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad-30408. [email protected]

2

Soil microorganisms are capable of producing auxins from its physiological precursor, L-tryptophan (L-TRP). Significant improvement in growth and yield of plants has been reported by applying L-TRP directly to soil, but its effectiveness through compost has yet not been reported. In the present study compost was prepared from fruit and vegetable waste material and enriched with 25% (44 kg ha-1) of full dose (175 kg ha-1) of N fertilizer for maize. Pure auxin, indole 3-acetic acid (IAA) and L-TRP (precursor), were blended with respective batches @ 10 mg kg-1 compost for the value addition of Nenriched compost. Comparative effectiveness of IAA or L-TRP-blended N-enriched compost was studied, in the presence or absence of 50% (88 kg N ha-1) of full dose of N fertilizer, through pot and field trials. Compost treatments were applied @ 300 kg ha-1, and compared with full dose of N fertilizer. Results indicated that N-enriched compost with or without IAA supplemented with half dose of N fertilizer was as effective as full dose of N fertilizer in improving growth and yield of maize, saving 25% N fertilizer. However, precursor (L-TRP)-blended compost was found better than pure auxin (IAA)-blended, when both were compared with full dose of N fertilizer. It significantly improved growth, yield and nutrient uptakes (up to 8.5, 10.2 and 21% respectively) of maize over full dose of N fertilizer. The technology bears its promise not only to improve crop yield on sustainable basis but also reduce huge piles of organic wastes causing environmental pollution.

Serpentine soils and vegetation of northwestern North America EARL B. ALEXANDER Soils and Geoecology 1714 Kasba Street Concord CA 94518 U.S.A. [email protected] Keywords: ultramafic, geoecology, British Columbia, Yukon, Alaska Ultramafic rocks with serpentine soils are widely distributed in accreted terranes southwest of the Rocky Mountain trench-Tintina fault zone and in Alaska-type bodies of British Columbia and Southeast Alaska. Although the areas of serpentine soils are small, many of them have vegetation that is distinctly different than that on adjacent soils. Soil classes in the World Reference Base and Canadian (in parentheses) systems are predominantly Cambisols (mostly Eutric Brunisols, but with Dystric and Humo-Ferric Brunisols where tephra or glacial drift have been deposited over the serpentine materials). Regosols (Orthic Regosols), Phaeozems (Mellanic Brunisols), and Luvisols (Gray Brown Luvisols) are also represented by serpentine soils. The most distinctive feature of the serpentine soils, other than the serpentine minerals inherited from the parent materials, is low exchangeable Ca/Mg ratios. This is the soil property that has the greatest effect on serpentine plant distributions. The common serpentine plant communities are alpine tundra, savanna, and forest. Most of the forests are coniferous (for example; white spruce, subalpine fir, and Douglas-fir), but paper birch (Betula papyrifera) is common toward the north and aspen (Populus tremuloides) is a successional species, along with lodgepole pine (P. contorta). Shrub species and herbs differ from north to south, although some shrubs such as low juniper (J. communis) are widespread on serpentine. Some of the more common genera of grass and sedges, from coldest to warmest, are Arctagrostis, Carex (C. bigelovii), Festuca (F. altaica), Calamagrostis, Pseudroegnaria (P. spicata), and Poa (P. secunda). Bryophytes and lichens are common ground cover toward the north and near the Pacific Coast.

Preferential flow of gas in soil SUZANNE E. ALLAIRE1 1

Horticultural Research Center, Université Laval, Québec, Qc, Canada, G1K 7P4 [email protected]

Keywords: gas movement, soil physics, macropore flow, heterogeneity Preferential flow (PF) is known to favour faster movement of solutes in soil toward surface and ground waters. PF seems as important for gas flux in soils especially for plant and biological respiration, oxidation, volatilisation of molecules, and for other processes. The goal of the project was to measure the relative importance of PF of gas under different soil conditions. Small, large, intact, and repacked soil columns were used to evaluate in laboratory the impact of soil heterogeneity on the PF of gas by diffusion. Macropores may increase gas diffusion by an order of magnitude. The impact of PF will further be discussed relative to gas diffusion in soil with macroporosity.

A history of soil classification in Canada DARWIN ANDERSON Department of Soil Science, University of Saskatchewan, Saskatoon, SK, S7N5A8 [email protected] Keywords: soil taxonomy, pedology, soil survey The origins of soil classification in Canada go back to the first soil surveys nearly a century ago. The first soil mapping in Ontario in 1914 followed a system developed in the USA and adapted to Ontario. It was based on soil colour and texture, with only nine series recognized for much of southern Ontario. Surveys using provincial classifications began in the Prairie Provinces in the 1920s. Many elements of the classifications used are evident in J.H. Ellis’ 1932 paper entitled “A Field Classification of Soils for Use in the Soil Survey”. The classification recognizes the soil zone as the highest category, consistent with early work by Ellis, A.H. Joel in Saskatchewan and F.A. Wyatt in Alberta. Subdivisions within the soil zone were the combination, association and associate, the latter similar to a soil series. Following a quiet period for pedology during the Great Depression and war years, the first meeting of the National Soil Survey Committee (NSSC) was held in Quebec in 1945. The NSSC, later the Canada SSC, brought together Canadian (provincial and federal) soil surveyors, pedology professors from the universities, and researchers in soil management. Generally there were representatives from the American soil survey community. Meetings every two to three years dealt with refinements to an emerging classification system. The 1955 meeting in Saskatoon was a milestone, in that a taxonomic system was introduced, in which higher hierarchical levels are conceptual, based on definition of a central concept. The Sub-Committee on Classification decided to continue with a Canadian system, not join the American effort that eventually led to Soil Taxonomy, although joint work is evident as both taxonomies developed. The Organic Order was added as the seventh order at the 1965 meeting at the Universite Laval, Quebec. The 1968 meeting in Edmonton resulted in a move to a more definitive system, and diagnostic horizons with defined criteria. There were major revisions to the Podzolic and Brunisolic orders, and the Luvisolic Order was added as the eighth order. “The System of Soil Classification for Canada” was published officially in 1974 as Publication 1455 of Agriculture Canada. It was a durable binder suitable for field use and able to accept later revisions. Eight orders, guidelines for describing profiles, and an interpretive classification, soil capability for agriculture, are included. A hard-cover edition entitled “The Canadian System of Soil Classification” was published by Agriculture Canada as Publ. 1646 in 1978. The Cryosolic order was included and, for the first time, a key for classifying soils. A second edition with revisions to the Gleysolic and Organic orders was published in 1987. The third edition (1998) includes a more complete key and a tenth order, the Vertisolic Order. Despite a present attitude of a job completed, it is evident that soil taxonomy in Canada is an enterprise that will continue to evolve as knowledge of our soils grows.

Properties of organic matter in a Chernozemic to Luvisolic sequence in soils at the grassland- forest transition DARWIN ANDERSON Department of Soil Science, University of Saskatchewan, Saskatoon, SK, S7N5A8 [email protected] Keywords: Gray Luvisol, Chernozem, humic acids, fulvic acids, carbon stores Soils at the grassland forest ecotone range from Black Chernozem soils under grassland to Gray Luvisol soils under aspen forest. Organic matter stores are somewhat higher in Chernozems and the OM is closely associated with mineral colloids in Ah and B horizons. The Gray Luvisols have nearly equivalent stores of OM, mainly as LFH or organic horizons at the soil surface, and at low concentrations distributed to considerable depth. More structurally complex, higher molecular weight humic acids are dominant in Chernozems, with about two-thirds of the OM present as clay-humus complexes. More soluble, organic materials of lower molecular weight ( fulvic acids) are the main OM component in Gray Luvisols, particularly in illuvial Bt horizons. Both visible fragments and the nature of humic materials suggest that charcoal accounts for much of the OM in surface horizons of Gray Luvisols, whereas clay-humus complexing is more important in Ah horizons of Chernozems.

Decrease in C availability following the cultivation of a forage stand DENIS A. ANGERS1, JAMES D. MACDONALD1, PHILIPPE ROCHETTE1, MARTIN H. CHANTIGNY1, ISABELLE ROYER1, MARC-OLIVIER GASSER2 1

Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd, Québec, QC, Canada, G1V 2J3 2 Institut de recherche et développement en agroenvironnement, Québec, Canada, G1P 3W8 [email protected] Keywords: carbon, inversion tillage, water-extractable carbon, soil respiration, grassland Mixed cropping systems such as those practiced in dairy production usually involve periodic cultivation of perennial forage stands. By incorporating crop residues (above and below ground) inversion tillage increases the contact between fresh organic matter and the soil matrix. The incorporation of crop residue may increase or decrease C availability. The purpose of this work was to monitor the early changes in C availability following ploughing by inversion tillage of a perennial forage stand. In the fall of 2007, two long-term research plots were divided into 16 subplots (2 treatments x 4 replicates x 2 long-term plots) that were either cultivated by inversion tillage or chemically treated with herbicide (non-tilled). One of the two long-term plots had received large doses of liquid swine manure annually since 1978 (100 m3 ha-1) and the other was an unfertilized grassland (0 m3 ha-1). The plots were seeded to timothy and were turned and renewed each 7 years. Carbon availability was characterized by the water extractable fraction and field measurements of soil respiration. In both the unfertilized and fertilized plots, the cumulative emissions of CO2 were 30 and 18% lower, respectively, in the soil that had undergone inversion tillage compared to the non-tilled soil. Likewise, in the unfertilized plot, on average, the quantities of water-extractable organic carbon (WEOC) were 35% lower in the ploughed than in the non-tilled treatment. The non-tilled soils had high concentrations of WEOC in the surface profile in the period immediately after treatment, but these concentrations decreased over time. By the end of the monitoring period, quantities of WEOC in the non-tilled soils were similar to those submitted to tillage. Differences in respiration rates following inversion tillage may be in part explained by the incorporation of the plant residues in a zone of lower temperature and oxygen levels. However, the immediate reduction in WEOC after tillage also suggests that decomposing organic material is being adsorbed to mineral surfaces. This process may be, in part, responsible for reductions in respiration and may be acting as a protection mechanism for organic carbon. These results provide additional evidence that inversion tillage may result in carbon accumulation at depth in the soil profile.

The effects of soil resources on tree neighborhood dynamics in sub-boreal spruce forests of British Columbia RASMUS ASTRUP1, K. DAVID COATES2, ERICA B. CLOSE1 1

Bulkley Valley Centre for Natural Resources Research and Management, Box 4274, Smithers, BC, V0J2N0; 2 British Columbia Ministry of Forests and Range, Research Section, Bag 6000, Smithers, BC V0J2N0 [email protected] Keywords: forest dynamics, soil nutrient regime, sub-boreal spruce zone, SORTIE-ND Traditional even-aged forest management has relied on the concept of site index to characterize productivity for single-species stands. Site index is a critical component of many growth and yield models used to project stand growth, however, it provides little insight into how the competitive interactions among tree species in complex stands may be affected by resource gradients. Previous research in forest community dynamics has divided competitive interactions among trees into shading and crowding interactions, where neighbor trees shade each other and compete for underground resources (Canham et al. 2004). We used a multiple working hypotheses framework and maximum likelihood methods to determine if a soil resource gradient affected tree neighborhood shading or crowding interactions, or simply affected the maximum growth rate of individual trees. We sampled 1,952 lodgepole pine (Pinus contorta), interior spruce (Picea glauca×engelmanii), and subalpine fir (Abies lasiocarpa) trees ranging from highly suppressed to dominant in canopy position. Sampling targeted a range of stand types, competitive relationships, and soil resource conditions. Neighborhood trees within an 8 m radius were measured and used to model the amount of light reaching each sampled tree (with SORTIE-ND), and the amount of crowding experienced by each sample tree (with a neighborhood competition index). We classified soil nutrient regime according to B.C.’s Biogeoclimactic Classification System and measured tree growth as the average annual radial increment over the past five years. Models were compared that predicted tree growth from tree size (diameter), light, and crowding and allowed those relationships to change with soil nutrient regime. In our best models, the maximum growth rate of trees increased with increasing soil nutrients and the effect of crowding decreased with increasing soil nutrients, suggesting that underground competition has a more adverse effect on tree growth on poor sites then on rich sites. The effect of shading did not change with soil nutrients, suggesting that trees respond similarly to light across site types. Canham, C. D., LePage, P. T. and Coates, K. D. 2004. A neighborhood analysis of canopy tree competition: effects of shading versus crowding. Can. J. For. Res. 34: 778-787.

Limited impact of warming and defoliation on nitrogen dynamics in a rough fescue grassland BEHNAZ ATTAEIAN*1, SCOTT X. CHANG 1, JAMES F. CAHILL 2 1

Dept. of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2E3 Biological Sciences Centre, University of Alberta, Edmonton, Alberta, T6G 2E9 [email protected]

2

Keywords: global warming, defoliation, nitrogen cycling In Canada, temperature has risen about 1.2°C over the last 50 years in Prairie Provinces (Natural Resources Canada 2007). Higher temperature may influence productivity and sustainability of rangeland ecosystems, which are an essential part of the cattle industry in Canada. We need to know how to maintain the productivity and carbon sequestration function of rangelands faced with global warming and overgrazing. The “Law of the Minimum” states that productivity in an ecosystem is proportional to the availability of the most limited nutrient. Rangeland ecosystems are often Nlimited. Therefore, nitrogen availability can regulate productivity and carbon fixation processes in rangeland ecosystems. Climate change models overestimate carbon fixation/sequestration by not considering the nitrogen deficiency in natural ecosystems (Hungate et al. 2003). In rangeland ecosystems, the effect of global warming may be influenced by grazing. The purpose of this study was to investigate the temperature sensitivity of nitrogen dynamics in response to grazing in a rangeland ecosystem. Soil temperature was increased using open top chambers (OTCs), a standard passive tool to increase air and soil temperature in high-latitude areas (Marion et al. 1997). As the OTC’s design prevented cattle grazing, grazing was simulated by defoliation through manual clipping to a height of 5 cm. The study site was located in a remnant grassland of aspen parkland in the grassland-forest transition zone. The response of available nitrogen, nitrogen mineralization and nitrous oxide emission to warming and defoliation were studied over a two-year period (2006-2007). Soil and gas samples were collected monthly during the growing season. Data loggers were used to record soil temperature and moisture in 15 min intervals during the growing season. Nitrification appeared to be the dominant process affecting nitrogen dynamics; however, nitrogen dynamics seems little affected by warming and defoliation treatments. Reference List Biello, D. 2007. Conservative climate, Scientific American 296 (4):16 Hungate, B. A., Dukes, J.S., Shaw, M.R., Luo, Y. and Field, C.B. 2003. Nitrogen and climate change. Science, 302: 1512-1513. Marion, G.M., Henry, G.H.R, Freckman, D.W., Johnstone, J., Jones, G., Jones, M.H., Levesque, E., Molau, U., Molgaard, P., Parsons, A.N., Svoboda, J. and Virginia, R.A., 1997. Open-top designs for manipulating field temperature in high-latitude ecosystems. Global Change Biology, 3 (Suppl. 1) 33-34. Natural Resources Canada, September 2007. www.adaptation.nrcan.gc.ca

Quantifying soil carbon pools: the influence of trees in temperate agroforestry systems AMANDA D. BAMBRICK*1, JOANN K. WHALEN1, NARESH V. THEVATHASAN2 AND ANDY M. GORDON2 1

Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, QC; University of Guelph, Guelph, ON; [email protected]

2

Keywords: agroforestry, soil organic carbon, intercropping Tree-based intercropping (TBI) is an agroforestry system where a crop, generally an annual, is planted between established tree rows. TBI systems have a greater potential for carbon storage than conventional cropping systems because (1) carbon is stored in the biomass of growing trees and (2) trees provide additional carbon inputs (leaves, roots) that contribute to soil organic carbon (SOC) storage. Since trees are grown in rows, spaced 8 to 15 m or wider across the field, this could lead to considerable spatial heterogeneity in the SOC content. The objectives of this research were to quantify the horizontal and vertical spatial variation of SOC in TBI systems, and to compare SOC pools in autumn 2007 with historical pools in TBI systems, thus quantifying temporal changes in SOC storage. Soils were taken for SOC analysis from a TBI research site in Guelph, Ontario. At Guelph, 23-yearold hybrid poplar and Norway spruce were intercropped with corn. Results from the site indicate that the SOC content was affected by the presence of trees in the top 0-5 cm layer, but not in deeper layers. There was a significant (P<0.05) decrease in SOC content with increasing distance from a row of Norway spruce, but the SOC content was similar in samples taken at 1, 3 and 6 m from the hybrid poplar row, likely a result of more widely-dispersed litterfall. The SOC pools in the top 5 cm ranged from 14.2 to 16.3 Mg C ha-1 with hybrid poplar, and up to 15.7 Mg C ha-1 with Norway spruce. A nearby conventionally managed agricultural field contained 12.8 Mg C ha-1 to the same soil depth. These results suggest that TBI systems may have a larger SOC pool than conventionally managed agricultural systems.

The natural regeneration potential of Douglas-fir after wildfire J.S. BARKER*1, S.W. SIMARD1, M.D. JONES2, AND D.M.DURALL2 1

Department of Forest Sciences, University of British Columbia, Vancouver BC V6T 1Z4 Department of Biology and Physical Geography, University of British Columbia Okanagan, 3333 University Way, Kelowna, British Columbia V1V 1V7 Canada [email protected]

2

Keywords: wildfire, natural regeneration, ecomycorrhizae, Douglas-fir The McLure fire of August, 2003, affected over 26,000 hectares in the interior of British Columbia. The aim of this study was to determine the impact of fire severity and clearcutting on Douglas-fir regeneration potential in the Interior Douglas-fir biogeoclimatic zone. The study design consisted of five treatments that compared a range of disturbances: High Severity Burn (no canopy), Clearcut (no canopy), Screefed Clearcut (no canopy), Low Severity Burn (closed canopy), and Undisturbed Forest (closed canopy). At each of four replicate sites per treatment, 1000 seeds were sown in late spring of 2004. The natural regeneration potential of Douglas-fir was assessed by measuring seed germination, seedling survival, shoot height and biomass, water use efficiency, foliar nutrients, and mycorrhizal colonization. All five treatments were compared for natural regeneration potential in 2004 only, because the Undisturbed Forests and Low Severity Burn treatments had high mortality in 2005. The High Severity Burn and two clearcut treatments were compared for regeneration potential from 2004 to 2006. Seed germination was above 30% in all treatments, but natural regeneration potential in the Low Severity Burn and Undisturbed Forest was low due to high mortality and poor growth. There were no significant differences in seedling survival between the High Severity Burn and clearcut treatments. However, seed germination was significantly higher in the Screefed Clearcut than Clearcut or High Severity Burn treatments, resulting in a higher number of seedlings. The High Severity Burn seedlings had significantly higher shoot height and biomass, and foliar N and P content, but there no effect on water use efficiency. Preliminary analysis of the mycorrhizal colonization data indicates that mycorrhizal colonization and diversity were reduced to the greatest extent in the High Severity Burn. This reduction, however, had no apparent effect on the other measures of natural regeneration potential (e.g., growth and survival). Overall, the treatments with the greatest disturbance severity (High Severity Burn and Screefed Clearcut) had the greatest natural regeneration potential.

Stable-isotope probing to identify active methane-oxidizing bacteria in a BC lodgepole pine plantation soil NATHAN BASILIKO1,2,3, PER BENGTSON1*, MARC DUMONT3, SUE J GRAYSTON1, MELISSA HILLS4, J COLIN MURRELL3, RÉAL ROY4 1

University of Toronto Mississauga Department of Geography, 3359 Mississauga Road North, Mississauga ON L5L 1C6 Canada 2 University of British Columbia Department of Forest Sciences, 2424 Main Mall, Vancouver BC V6T 1Z4 Canada 3 University of Warwick Department of Biological Sciences, Gibbet Hill Road. Coventry, CV4 7AL UK 4University of Victoria Department of Biology, PO Box 3020 Station CSC, Victoria, BC V8W 3N5 Canada [email protected] Key words: PLFA-SIP, nucleic acid-SIP, methanotroph Upland forest soils are an important sink for the atmospheric greenhouse gas methane (CH4) through the activity of CH4-oxidizing bacteria (MOB). However, many purported MOB detected with molecular fingerprinting techniques in these sites have evaded in vitro cultivation and isolation. Therefore, we used 13C phospholipid fatty acid-(PLFA) and nucleic acid-stable isotope probing to identify active MOB in three horizons of a podzolic BC lodgepole pine plantation forest soil. The 13C incorporation into PLFAs differed between horizons, with small 13C incorporation in the LFH horizon and large and similar incorporation in the Ae and Bhf mineral horizons. The PLFAs 18:1ω7 and br17:0 were most enriched, followed by i17:0 and the unidentified PLFA (x1). Analysis of 13C incorporation patterns into the different PLFAs revealed that the microbial community incorporating the 13C label also differed between horizons. Two independent statistical analyses suggested that this may be linked to variation in CH4 oxidation rates. 13C incorporation was positively dependent on both the absolute and relative concentration of x1 in the whole microbial community, as well as the relative concentration of x1 in the CH4 oxidizing community, reinforcing the observation that variations in the community structure of CH4 oxidizers can be directly related to variations CH4 oxidation rates. DNA and RNA-SIP approaches using 16S rDNA fragments were too insensitive to conclusively identify active MOB, even after 1mo of enrichment under 50 and 10,000ppm 13CH4. However both PLFA and (unlabeled) pmoA gene sequence data indicated that CH4 oxidizers in this soil belong to the yet uncultivated ‘upland soil cluster alpha’. ‘Potential’ CH4 oxidation rates measured post-13C enrichment in soil samples taken from individual horizons were fastest in the organic horizons. Thus, potential oxidation exhibited the opposite pattern to 13C incorporation, suggesting that potential oxidation assays may be poorly related to in situ oxidation rates, or alternatively, that MOB in the organic horizon did not use CH4 in an assimilatory (anabolic) pathway.

LFH to O – or was that peat? Transitions in landscape carbon storage, process and thought ILKA E. BAUER Sir Wilfred Grenfell College, Memorial University of Newfoundland, University Drive, Corner Brook, NL A2H 6P9 [email protected] Keywords: carbon storage, organic soil, boreal forest, catena, carbon cycling Rates of soil carbon sequestration and soil carbon storage can differ by orders of magnitude between different boreal ecosystem types. Soil temperature and drainage, vegetation composition and dynamics, litter chemistry, disturbance, and long-term soil development all affect carbon retention over varying time scales, and interactions of these factors produce complex mosaics of mineral and organic soil types across boreal landscapes. Reflecting the complexity of these relations, studies that contribute to our understanding of forest soil carbon dynamics have come from a series of disciplines. These include ‘classic’ soil science as well as geography, forestry, botany, biogeochemistry, and various branches of ecology that range in scale from landscape ecology to detailed studies of microbial community structure and dynamics. Although many examples of successful interdisciplinary collaborations exist, different theoretical frameworks, vocabularies, and methodological approaches can hinder communication between disciplines, and the different time scales implied by different types of research questions often make results hard to extrapolate. This presentation explores some of these issues by contrasting different approaches to the study of organic soils. Questions examined range from long-term development (What controls organic soil formation, long-term carbon sequestration and storage?) to current dynamics (Rates of litter production, turnover, and effects of short-term environmental fluctuations). Data presented draw on case studies of soil catenas in central Saskatchewan as well as the published literature, and methods explored range from paleoecology to modelling and manipulative studies. Rather than presenting a conclusive set of results, the aim is to highlight both overlaps and differences between these approaches, and to foster discussion between the various disciplines.

Introduction of exotic earthworms in the boreal forest of western Canada ERIN M. BAYNE1, ERIN CAMERON1, DAVID W. COLTMAN1, AND M. JILL CLAPPERTON2 1 CW 405, Biological Sciences Centre, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9 2 Agriculture Canada, Lethbridge, Alberta. 5403 1st Avenue South. T1J 4B1

[email protected] Keywords: earthworm, invasion, roads, boreal forest Recreational and industrial development is expanding rapidly in the boreal forest of western Canada. Concerns exist that such activity is facilitating the introduction and spread of non-native species such as exotic earthworms. The mechanisms by which earthworms are introduced and spread in forested systems are not well understood. Given the poor innate dispersal abilities of earthworms, we propose four major introduction mechanisms: 1) Direct introduction by humans via abandonment of fishing bait; 2) indirect dispersal by humans via vehicle traffic; 3) transport via waterways; or 4) “natural dispersal” via vertebrate predators. To test the plausibility of these various hypotheses, we sampled earthworms in forest stands near boat launches, linear features (roads & seismic lines), forest interiors, and remote shore lines of lakes in the boreal forest of northern Alberta, Canada. Boat launches and roads had a significantly higher probability of earthworm occurrence compared with the other locations. Species commonly used as fishing bait occurred more often near boat launches than near roads alone. These results suggest that both vehicle transport and bait abandonment are the major mechanisms of earthworm introduction in Alberta’s boreal. The consequences of these introductions remain unclear, but suggest that reduced road construction and regulations prohibiting the discarding of bait need to be considered to slow earthworm invasions. Spatial mapping of current earthworm distribution and rates of potential spread over the next 50 years will be discussed.

Dishing the dirt on soils: a soils of Canada website ANGELA BEDARD-HAUGHN1, LITO AROCENA2, DAN PENNOCK1 1

Department of Soil Science, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK S7N 5A8; Environmental Science and Engineering, University of Northern British Columbia, 3333 University Way, Prince George, BC V2N 4Z9 [email protected] 2

Keywords: pedology, soil classification, extension, education One of the priorities of the Pedology Subcommittee of the CSSS is to develop a new, user-friendly Soils of Canada website. With support from the Capling Fund at the University of Saskatchewan, development is currently underway. The website will provide maps, soil descriptions, and information about the Canadian System of Soil Classification for students and folks working in cognate disciplines (ecology, plant sciences, etc). Although the main target audience is non-specialists, the Soils of Canada website will also include a number of maps and images available for download and as such will provide a useful teaching tool and general research reference for soil scientists across Canada. As part of the initiative, leading authorities on each of the ten soil Orders will be preparing detailed review articles for submission to the Canadian Journal of Soil Science. This presentation will provide a sneak preview of the new Soils of Canada website and an opportunity for CSSS members to share their suggestions and comments to ensure this exciting initiative will realize its full potential as a valuable teaching and extension tool.

Model averaging for soil water retention curve ASIM BISWAS*, BING C. SI Department of Soil Science, University of Saskatchewan, Saskatchewan, Canada [email protected] Key words: Soil water retention curve, model selection, AIC, selection bias, model uncertainty Soil water retention curve, one of the most important soil hydraulic properties, is the relationship between soil water content (θ) and the soil water potential (ψ). Knowledge of the soil hydraulic properties is needed to describe and predict water and solute transport, available water for plant uptake, soil erosion, as well as heat transport near the soil surface. There are several models in describing this property. However, each model has its own uncertainty and none of these models fit all soils. The objective of this paper is to examine the possibility of reducing model uncertainty through averaging a set of candidate models for soil water retention curve. An experimental dataset of soil water retention curve is selected from archive for this study. This dataset is fitted with different existing models for predicting water retention curve like van Genuchten model, Kosugi model and Brooks and Corey models. These models are fitted based on Mualem, Burdine, and general equation. Akaike Information Criterion (AIC) is calculated from the residual sum of squares. From the AIC values the likelihood of the model is calculated and the relative weights are assigned to each candidate model based on their importance. The parameter estimation and the model averaging are done from the weighted average of a few models. The average model provides with a better estimation of water retention curve and reduces the biasness in selection of models. The uncertainty in models is also being reduced for predicting the soil water retention curve.

Scaling properties of depth controlled spatial pattern of soil water storage ASIM BISWAS*, BING C. SI Department of Soil Science, University of Saskatchewan, Saskatchewan, Canada [email protected] Key words: scaling, spatial variability, multifractal detrended fluctuation analysis, monofractal, multifracta Knowledge about the spatial pattern of soil water storage is very important in monitoring soil water balance and validating different models. The scaling properties of this spatial pattern help in transferring information from one scale to another. The objective of this paper is to characterize if the variability of soil water storage exhibits simple scaling or multiscaling at different depths. The soil water content was measured at the depth of 20 cm through 140 cm at 20 cm interval along a transect at St Denis National Wildlife Area, Saskatchewan, Canada using neutron probe during the fall season of 2007 (12 October). The transect had 128 points with 4.5 m sampling interval. The water content showed localized trend and non-stationarity in their distribution which is a great challenge in scaling analysis of soil water storage. Multifractal detrended fluctuation analysis was used in characterizing the spatial pattern of soil water storage. The first order of detrending was selected from different orders of detrending as the best detrended polynomial function to obtain a stationary series for scaling analysis based on the significance test between different orders of polynomial. The linear fit of double log plot of series (r=0.99 to 1.00) indicate the presence of scaling laws. The plot of mass exponents, τ (q ) derived from fluctuation function, q values from -20 to 20 and q values indicate the increase in linearity of the curve with the increase of depth of soil water storage. The degree of non-linearity of the curve indicates the degree of heterogeneity of their scaling behaviour. The widest multifractal spectrum [ f (q )vsα (q )] at surface indicates the need of hierarchy of scaling exponent (multiscaling) to represent the scaling property accurately. The network of grass roots at the surface soil and the various degree of extraction of water by them make the spatial distribution of soil water storage highly variable. The variability in the soil water storage gradually decreases with depth indicating the presence of simple scaling relationship and can be explained by monofractal behaviour. The information about the scaling nature of soil water storage as controlled by depth will help in assessing land atmosphere interaction, infiltration, drainage, recharge and various engineering performance.

Where did all the N go? ERIC BREMER*1, HENRY H. JANZEN2, ROSS H. McKENZIE3, ELWIN G. SMITH2 1

Symbio Ag Consulting, Lethbridge, AB; Agriculture and Agri-Food Canada, Lethbridge, AB; 2 Alberta Agriculture and Rural Development, Lethbridge, AB; [email protected] 2

Keywords: nitrogen losses, nitrous oxides, soil organic matter Production and subsequent loss of N fertilizer accounts for a high proportion of greenhouse gas emissions from agricultural systems in Canada. We determined N balances at national and field scales (long-term cropping studies) to evaluate how much N is lost from agricultural systems and what options might be used to reduce them. Preliminary analysis indicates that N losses can amount to almost half of added N, although losses were considerably lower in some cropping systems.

Patterns in forest soil microbial community composition across a range of regional climates in western Canada BETH F.T. BROCKETT1*, SUSAN J. GRAYSTON1, CINDY E. PRESCOTT1 1

Belowground Ecosystem Group, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4 [email protected] Keywords: Forests, microbial communities, enzyme activities, PLFA Soil microbial communities can be characterized by community structure and function (community composition) across a spectrum of spatial scales, and variation in soil microbial composition has been associated with a number of environmental gradients. This study investigates the structure and function of soil microbial communities under mature, undisturbed forested sites across a range of regional climates in British Columbia and Alberta, and also examines the variation in community composition within sites. Phospholipid fatty acid analysis was used to investigate the structure of soil microbial communities and total soil microbial biomass at each site. Extra-cellular enzyme assays established the functional potential of the soil microbial community at each site. Multivariate analysis of the data showed that the soil microbial communities under different forest types did significantly separate along the regional climate gradient by both community structure and function, despite high local variation in the communities. Soil moisture content and soil organic matter concentration consistently exhibited the strongest relationship with microbial community characteristics, although the functional and structural responses to the external drivers were different. Microbial community function and structure also changed with soil depth but not with time of sampling. Microbial community function was related to the regional annual average precipitation gradient. Most of the locations exhibited unique microbial community functional profiles in their soil layers; however the enzyme activities in the samples from the driest (Ponderosa Pine) and wettest (Mountain Hemlock) locations were notably different from each other and from those of the other locations, especially in the organic layers. The moist maritime-influenced Coastal Western Hemlock (CWH) forest exhibited microbial community structural characteristics which were unique from those of the other forest locations. The higher abundance of bacteria relative to fungi in the CWH forest soils may be related to the significantly higher available nitrogen concentrations at this site.

A question of scale: Are ectomycorrhizal fungi associated with fine scale soil phosphatase activity? DENISE BROOKS*1, MELANIE JONES2, SUSAN GRAYSTON1 1

University of British Columbia,Vancouver, BC University of British Columbia Okanagan, Kelowna, BC [email protected]

2

Keywords: ectomycorrhizae, hyphae, phosphatase, function, scale Tree growth is influenced by the ectomycorrhizal fungal community present on individual host trees. This growth effect may be influenced by the ability of ectomycorrhizal fungal species to acquire and transport nutrients to the host and by the carbon demand on the host to support these fungi. Though functional diversity in nutrient mobilization by ectomycorrhizal fungal hyphae has been demonstrated with fungal isolates in microcosms, it remains a challenge to demonstrate functional diversity in the field; not only due to the difficulty of identifying the fungal species present as hyphae in the soil, but also due to the fine scale patchiness of forest soil nutrient resources. Nutrient mobilizing enzymes such as phosphatase associated with these resource micro-sites have been visualized using an in-situ imprint technique, and a marked change in phosphatase activity has been observed between younger and older post-fire disturbance forest plots of interior Douglas-fir/paper birch (Betula papyrifera) located in the ICH of south central British Columbia. We collected small soil samples (0.25 g) from visualized phosphatase-active soil micro-sites at three replicate sites of the four age class forest stands. Enzyme micro-sites were sampled from one 20 cm x 20 cm plot in each stand using a root window to access the soil profile. Three phosphatase-active micro-sites were sampled from the organic and 3 from the mineral layer of each plot, and 3 samples were taken from each layer where no activity was visualized. Using terminal restriction fragment length polymorphism (TRFLP), we characterized the fungal assemblages associated with phosphatase-active soil micro-sites and compared these to the assemblages found in samples taken from areas where no phosphatase activity was visualized. Additionally, a TRFLP library was constructed from local ectomycorrhizal root-tip DNA and used to asses the spatial distribution ectomycorrhizal fungal hyphae in relation to phosphatase-active microsites. Multi-response permutation procedure (MRPP) was used to evaluate differences between the total fungal assemblages of micro-site samples and found that while micro-site sampling was able to identify broad differences between the total fungal assemblages present in the age classes of the forest chronosequence, the sampling effort was not sufficient to reveal the expected differences between soil layers, much less differentiate between phosphatase-active micro-sites and non-active soil areas. MRPP analysis of the ectomycorrhizal fungal species assemblages found on the younger stands produced similar results to those seen for the total fungal assemblages. However there were not enough ectomycorrhizal fungal species identified on the older stands to permit valid comparisons. While micro-site sampling has the potential to connect in-situ soil function to ectomycorrhizal fungal species, the minute scale of the sampling method needed to target in-situ enzyme activity and the sampling intensity necessary to determine fine scale differences between micro-sites needs further development and investigation.

Effect of woody debris on soil and microbial characteristics during oil sands reclamation ROBYN L. BROWN*1, M ANNE NAETH1 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta [email protected]

Keywords: reclamation, restoration, woody debris, oil sands, soil microorganisms Boreal forests in the Athabasca Oil Sands Region are being degraded due to oil sands operations. Oil sands companies are required by regulation to reclaim all disturbed land to predisturbance ecosystems with equivalent land capability. Current reclamation methods depend on cover soil application to return seed bank, nutrients and microbial diversity. Adding woody debris to a degraded landscape may enhance reclamation by aiding, and possibly quickening, the recovery of mesofauna, microorganisms, soil nutrients, soil water and floral diversity. Woody debris may provide a source of plant seeds and propagules. Woody debris decreases erosion and creates microsites where ecosystem function is maintained and seeds and seedlings are protected. Invertebrates and microorganisms that accompany woody debris can enhance soil formation processes. This research will determine if applying woody debris to degraded land will affect soil nutrients and microbial populations. The research site was constructed in 2005 and is arranged to compare treatments with and without woody debris on peat cover soil. Soil samples were collected and analyzed for available nutrients, C:N ratio, total organic carbon, electrical conductivity, sodium adsorption ratio and particle size analysis. Rhizosphere samples from six plant species were collected and analyzed for microbial biomass carbon and glucosamine content.

Phosphorus forms and concentrations in soils from long-term rotations with different fertilization BARBARA J. CADE-MENUN1, DEAN C. JAMES1 1

Agriculture & Agri-Foods Canada, SPARC, Box 1030, Swift Current, SK S9H 3X2 [email protected] Keywords: organic P, N and P fertilization, wheat Phosphorus (P) is an essential nutrient for all living organisms, and thus is an important fertilizer for agricultural crops such as wheat. However, the rising cost of conventional P fertilizers has created an interest in alternate fertilizers such as composts, manures and biosolids. Traditional inorganic P fertilizers add only orthophosphate, an inorganic P form that is readily bioavailable. Alternate P fertilizers add orthophosphate, but may also add P in organic forms such as orthophosphate monoesters (e.g. sugar phosphates, phytic acid) and orthophosphate diesters (e.g. phospholipids, DNA) and complex inorganic P forms such as pyrophosphate and polyphosphate. All of these P forms may be found naturally in soils without P fertilization. Prior to adding alternate fertilizers to soils, it is important to understand the dynamics of natural P forms in soil, particularly their bioavailability and mineralization to orthophosphate for plant uptake. A useful tool for this type of research is a long-term field experiment with plots receiving both P fertilizers and no fertilization. In 1967, a long-term crop rotation experiment was established on a Swinton silt loam (Orthic Brown Chernozem) at the Semiarid Prairie Agricultural Research Centre (SPARC) near Swift Current, SK. The crop rotations were: fallow, wheat, wheat fertilized with nitrogen (N) and P, P only or N only; or continuous wheat fertilized with N and P or P only. In 1995, these plots were spit, so that one half received the prior fertilization, and the other half received no fertilizer. The objective of our research was to determine the changes in soil P forms and concentrations in soils after P fertilization was stopped, specifically comparing soils from 1995 and 2005. Our preliminary results show a marked difference in P forms and concentration after ten years without P fertilization. Organic P forms showed few differences among treatments. The concentration of organic P in soils with P fertilization was 149 mg kg-1; in soils without P fertilization it was 154 mg kg-1. In contrast the concentration of inorganic P was 131 mg kg-1 in P-fertilized soils, but only 82 mg kg-1 in soils without P fertilizers. Crop yield reductions were observed only in plots without N fertilization. These results suggest that soil P can remain, or become, plant-available for many years after fertilization in these plots. Further research is planned to investigate these changes, and the factors controlling them, in more detail.

Determination of estrogens in environmental samples using Enzyme-Linked ImmunoSorbent Assay (ELISA) EMMANUELLE CARON1*, CLAUDIA SHEEDY2 AND ANNEMIEKE FARENHORST1 1

Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada Agriculture and Agri-Food Canada, Lethbridge, Alberta [email protected]

2

Keywords: ELISA, estrogens Enzyme-Linked ImmunoSorbent Assays (ELISAs) provide for one of the simplest, quickest and cheapest detection methods for environmental contaminants. Estrogens are contaminants of importance because they are known endocrine disrupting compounds. As such, estrogens have shown adverse effects on aquatic organisms and wildlife at very low concentrations. Estrogenic compounds can be released in the environment by wastewater treatment facilities, farm runoff and application of solid waste or manure onto agricultural land. The three estrogens of interest in this study are 17βestradiol, estrone and estriol. The present poster describes the initial development of an ELISA for the determination of these three estrogens in environmental samples. Rabbits were immunized with a 17βestradiol-BSA conjugate synthesized using the Mannich reaction. Sera were collected and tested for their ability to detect estrogens. A coating conjugate was synthesized in which ß-estradiol-6-one-6(0carboxymethyloxime) was conjugated to OVA (ovine serum albumin) using the mixed anhydride reaction. A competitive ELISA was developed and a linear calibration curve was obtained for estrogens concentration ranging from 1 to100 ng/mL (final extract concentration). The ELISA 50 % inhibition (IC50) is 10 ng/mL while the limit of detection is 10 pg/mL. Further assessment and validation of the ELISA will include: estrogen determinations in environmental water samples and confirmation by LC-MS/MS.

Sorption of four estrogenic compounds by Alberta soils: the importance of spatial variability EMMANUELLE CARON1*, ANNEMIEKE FARENHORST1, JEANETTE GAULTIER1, TOM GODDARD2 AND CLAUDIA SHEEDY3 1

Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada Alberta Agriculture and Food, Edmonton, Alberta, Canada 3 Agriculture and Agri-Food Canada, Lethbridge, Alberta [email protected] 2

Keywords: sorption, estrogens, spatial variability Sorption by soil is an important process that influences the transport and persistence of organic chemicals, such as estrogens, in the environment. Estrogens are among a group of molecules referred to as endocrine disrupting compounds. They enter the environment by effluents from wastewater treatment plants, and application of solid waste or manure onto agricultural lands. The objective of this study was to measure soil sorption coefficients (Kds) for four estrogens, 17β-estradiol (E2), estrone (E1), estriol (E3), and the phytoestrogen, equol and to determine variations in those Kds at both the regional and field scales. Surface soils were collected from 40 agricultural fields throughout seven ecoregions in Alberta. For each site, samples were taken from upper-, mid- and lower-slopes. Soil properties (soil organic carbon content (SOC), pH, electrical conductivity, cation exchange capacity, and texture) were also determined to analyze the importance of soil properties on the variations of the measured Kds. All estrogens demonstrated a large variation in sorption among Alberta soils, particularly equol because the Kd values of the phytoestrogen ranged from 14 to 177 L/Kg. For the natural estrogens, Kd values ranged from 11 to 119 L/Kg for estrone, but only from 5 to 62 L/Kg for estriol and from 7 to 65 L/Kg for 17β-estradiol. Multiple regression and multiple discriminant analyses demonstrated that the variability of Kd values at both regional and field scales was best explained by differences in SOC. Soils from the Mixed Grassland ecoregion showed significantly lower SOC and Kd values relative to other ecoregions. At the field scale, soils from lower-slopes had significantly greater SOC and Kd values relative to soils from upper-slopes. Therefore, it can be concluded that, of the soil properties considered in this study, the spatial variability of the sorption behavior of all four estrogenic compounds could be best predicted by SOC.

Conservation tillage for potato rotations in Prince Edward Island M.R. CARTER, R.D. PETERS, C. NORANHA AND J.B. SANDERSON Agriculture and Agri-Food Canada, Research Centre, 440 University Avenue, Charlottetown, PEI, C1A 4N6, Canada [email protected]

Keywords: conservation tillage, potato, sandy loam, soil organic matter, soil structure Potato (Solanum tuberosum L.) farming systems are often associated with soil degradation due to their excessive use of tillage and production of low levels of crop residue in the potato year. Results from a 14-year study, initiated in 1994 on a fine sandy loam (Orthic Podzol) in Prince Edward Island (eastern Canada), were evaluated over a three-year (2003-2005) to assess the use of conservation tillage (CT), compared to conventional tillage, in 3-year (barley–red clover –potato) potato rotation. The CT strategy was to shift the primary tillage event for the potato phase from the autumn to spring, and to reduce the degree and depth of tillage. Mulches were used on all plots after potato harvest to provide soil cover over the cool season. Marketable potato yield, given for a 12-year period, was generally similar between the two systems. The CT system provided relatively high surface residue levels after potato planting, compared to the bare soil surface in the conventional tillage system. Soil organic matter and particulate organic matter were significantly increased at the 0-10 cm soil depth in the CT, compared to the conventional system. Soil structure was also improved under the CT system. Overall, use of CT in 3-year potato systems has the potential to maintain crop productivity and improve conditions at the soil surface.

Persistence of lincomycin in liquid swine manure and manure-amended soil and its transport in snowmelt runoff ALLAN CESSNA1 and SANDRA L. KUCHTA2* 1

Agriculture and Agri-Food Canada, Saskatoon, SK, Canada; Current address: National Hydrology Research Centre, 11 Innovation Blvd, Saskatoon, SK, Canada 2

Toxicology Graduate Program, University of Saskatchewan, Saskatoon, SK, Canada [email protected] Livestock manure containing antimicrobials becomes a possible source of these compounds to surface and ground waters when applied to cropland as a nutrient source. Veterinary antimicrobials have been detected in surface and ground waters in Canada, the United States and Europe; however, their environmental fate is not well known. Lincomycin is an antimicrobial administered to swine in the prairie region of Canada for the prevention of post-weaning diarrhea. Its potential for transport to surface waters via surface runoff and to leach to ground water was assessed by i) monitoring its presence in liquid manure from a confined animal feeding operation as a consequence of oral administration to weanling pigs during a 5-week period, ii) investigating its persistence during simulated manure storage and in manure-amended soil and iii) measuring its concentrations in snowmelt runoff over a 2-year period at two sites in Saskatchewan, Canada following fall (October) application of liquid manure from two commercial barns to crop and pasture land. LC-MS/MS was used to quantify lincomycin in all matrix extracts. Following 5 weeks of oral administration of lincomycin to weanling pigs in a commercial-scale barn, the amount of lincomycin in the cumulating liquid manure was equivalent to 32% of the dose administered to the pigs in their feed. During simulated lagoon storage, the concentration of lincomycin in fortified manure showed a rapid initial decrease during the first 6 days followed by a much slower dissipation over a period of 5 months. The average time required for 50% dissipation was greater than one year. Such persistence means that lincomycin may be present in lagoon manure when applied as an amendment to agricultural land since many lagoons are emptied every six months (early spring and late fall). Initial lincomycin concentrations in cropland amended with liquid manure at 60,000 to 95,000 L ha-1 ranged from 20 to 160 µg kg-1. There was a very slow decrease during the winter months when soil temperatures were < 0°C (October to March) followed by a more rapid decrease after spring snowmelt runoff when soil temperatures were warmer (April to September). During the latter period, the average time for 50% dissipation (DT50) was 7.8 ± 0.3 days such that, by mid-summer, lincomycin concentrations had decreased to non-detectable concentrations (< 0.5 µg kg-1). Snowmelt runoff was monitored weekly in 8 depressions on manure-amended cropland (2004) and 6 ephemeral wetlands on crop and pasture land (2005) until all water had infiltrated into the soil. Lincomycin was detected in all runoff samples in concentrations ranging from 0.038 to 0.73 µg L-1 confirming that the management practice of utilizing livestock manure as a plant nutrient source on crop and pasture land may result in antimicrobial transport to surface waters.

Potential nutrient mobilization capabilities of hyphosphere bacteria RONALD CHAN*1, DENISE BROOKS1, MELANIE JONES2, SUSAN GRAYSTON1 1

University of British Columbia,Vancouver, BC University of British Columbia Okanagan, Kelowna, BC [email protected]

2

Keywords: ectomycorrhizae, bacteria, hyphosphere, function, enzyme Ectomycorrhizal (EM) fungi provide nutrients to their host trees by means of hyphal networks that extend beyond nutrient-depleted rhizosphere soil. Foraging hyphae access organic nutrients by means of extracellular enzymes and also solubilize inorganic nutrients through release of organic acids and chelating agents. Recent work has shown that bacteria isolated from the mycorrhizosphere (EM root tips) demonstrate a greater potential to mineralize inorganic phosphorus than the bacteria isolated from bulk soil, indicating that the EM symbiosis may exert a selective pressure on the functional diversity of nearby bacteria (Calvaruso et al. 2007). To determine if the selective effect seen near EM root tips is also present in the hyphosphere, where foraging EM fungal hyphae are actively involved in nutrient acquisition, we incubated sand-filled mesh bags in a 60 year-old Douglas-fir / paper birch forest. Bacteria were isolated from three types of bags: hyphal in-growth, hyphal-exclusion, and totalexclusion (control). Isolates were assayed for production of phosphatase and β-N-Acetyl-Dglucosaminidase (NAGase). NAGase degrades chitin, a fungal and bacterial cell wall component, facilitating access to organic nitrogen. Preliminary results indicate that bacterial isolated from control bags have lower constitutive phosphatase and NAGase production than isolates from either the hyphal in-growth or hyphal-exclusion bags. The bacteria isolated from hyphal in-growth bags appear more functionally structured than the isolates from hyphal-exclusion bags. Bacteria of the same species isolated from hyphal in-growth bags exhibit opposing phosphatase and NAGase activities, with one isolate expressing high phosphatase and low NAGase while another isolate of the same species demonstrated the opposite behaviour. This inversion of enzyme production profiles was not evident in bacteria isolated from hyphal-exclusion bags. Reference List Calvaruso, C., Turpault, M., Leclerc, E. and Frey-Klett, P. 2007. Impact of Ectomycorrhizosphere on the Functional Diversity of Soil Bacterial and Fungal Communities from a Forest Stand in Relation to Nutrient Mobilization Processes. Microbial Ecology 54: 567-577.

Soil C stabilization: sensitivity to temperature and effects of landuse change SCOTT CHANG1, TESFAY TEKLAY1, CARMELA AREVALO1 AND JAG BHATTI2 1

Dept. of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2E3 Northern Forestry Centre, Canadian Forest Service, Edmonton, Alberta, Canada T6H 3S5 [email protected] 2

Keywords: soil organic carbon, stability, density fraction, soil particle size fraction, sensitivity. In order for soil systems to play a role in mitigating climate change, maintaining soil C stability is considered one of the key requirements for effectively sequestering organic C in the soil. We studied 1) the effects of landuse change on soil C stabilization by evaluating the distribution of soil organic C in density fractions along a hybrid poplar chronosequence, and 2) the stability of soil organic C by investigating the sensitivity of soil organic C (associated with different soil textural particle sizes) oxidation to temperature in a laboratory incubation experiment. In the first experiment, we studied the distribution and temporal changes of C in soil organic matter (SOM) density fractions in 2-, 5-, 11-, and 13-year-old (age as in 2006) hybrid poplar stands that form a chronosequence by sampling the stands in both 2004 and 2006. The soil was fractionated into light (LF, density < 1.6 g mL-1), occluded light (LFo, density < 1.6 g mL-1) and heavy (HF, density > 1.6 g mL-1) fractions. The results showed that C concentrations (g kg-1 of fraction) in the SOM density fractions decreased in the order of LFo > LF > HF, while the C/N ratio was in the order of LF > LFo > HF. The amount of C stored in the LF, LFo and HF fractions and bulk soil in the top 10 cm of soil was 149-504, 70-336, 1380-2876 and 1617-3776 g C m-2, respectively. From 2004 to 2006, C storage decreased in the LF and LFo fractions but increased in the HF fraction in the youngest stand. However, stand-age effects were likely muted by high inherent soil variability among the stands. Carbon storage in the light fraction was responsive in the short term to hybrid poplar plantation establishment. In the second experiment, we investigated the effects of landuse (including agricultural, hybrid poplar plantation, rangeland, and native forest) and temperature (7, 14 and 21 °C) on the mineralization of organic C associated with different soil particle size fractions (bulk soil, 250-2000 (medium to very coarse sand), 53-250 (very fine and fine sand), 2-53 (silt), and <2 µm (clay)) of soils. We found that after 286 days of incubation, the C mineralized as a % of the C content of the respective fraction increased with temperature and the C contained in the silt and very fine to fine sand fractons were more susceptible to microbial attack. However, landuse did not affect the sensitivity of organic C mineralization to temperature changes in the different soil particle size fractions. Our results show that increased storage of organic C in the heavy fraction might be a mechanism for increasing C storage and stability in the soil as hybrid poplar stands develop and increases in soil temperature in association with climate change will affect organic C mineralization regardless of the type of landuse.

Badger: the natural soil scientist WILLIAM K. CHAPMAN1, ROGER PACKHAM2 1

BC Ministry of Forests and Range Research Section 200-640 /Borland Street Williams Lake, BC V2G 5C9 2 BC Ministry of Environment 300 Highway 97 100Mile House, BC V0K 2E0 [email protected] Keywords: badger, soil texture, aeolian The badger (Taxidea taxus) is a red listed species in British Columbia. Its range has recently been determined to extend well into the central Cariboo Region of British Columbia. In this area, the badger selects a very narrow range in soil texture for burrow construction. Badger burrows come in different styles (hunting, natal, overwintering) but even with that range in uses, the preferred soil textural class is very specific. The burrows are typically found in aeolian deposits or occasionally in other well sorted parent materials (glacial fluvial, one case in volcanic ash) that have a similar textural range. There is some evidence to suggest that badgers have special sensory capability for soil texture. The narrow textural range for burrowing has implications for badger and badger habitat management. Soils in the ideal textural class have physical properties that in many ways make them ideal for burrow construction and underground habitation by badgers and other larger burrow utilizing mammals.

Modified stereo microscope to measure soil hydrophobicity HENRY W. CHAU*1 1

Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

[email protected] Keywords: hydrophobicity, microscope, contact angle Hydrophobicity measurement in soil is usually measured using capillary rise method, water drop penetration time, molarity of ethanol method or the mobile sessile drop method. These current measurement techniques for hydrophobicity are time consuming, difficult, non-versatile or require expensive equipment. The mobile sessile drop method seems to be the prominent method for measuring soil hydrophobicity because measurements are rapid and easy. One problem with this technique is that the equipment used may be expensive, as that is utilized primarily in application surface chemistry. Another issue is the versatility of this equipment. As we know microscopes and digital camera are prevalent in many labs. Modification of a microscope so that image of contact angle can be determined offers a potential cost effective solution for measurement of contact angle as well as addresses the flexibility issue, as different stages with different parameters can be built (Humidity, Temperature and Gas Atmosphere). This allows for measurements of contact angle under a variety of conditions, and may help in establishment of cause and effect relationships. The modified microscope in combination with image digitization and manipulations also offers a significant advantage over conventional methods, due to visual inspection of contact angle measurements and analysis static and kinetic changes in contact angle measurements. Development of a simple cost effective and versatile technique to accurately measure the degree of hydrophobicity would further assist in identifying hydrophobic soils and aid in the determination of cause and effect relationships. Recently we obtained contact angle measurements for fungal slide hydrophobicity, and we will further apply this soil hydrophobicity. This objective of this study is to determine if the modified microscope method is accurate in measuring soil hydrophobicity.

Development of physical soil quality indicators for a borrow and a control site in Alberta BALDEV S. CHHABRA1, NOORALLAH JUMA1, ARNOLD JANZ2 1

Research Associate and Professor of Soil Microbiology & Biochemistry, respectively, Department of Renewable Resources, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3 2 Land Conservation Specialist, Land Evaluation and Reporting, Alberta Environment, 12th floor Oxbridge Place, 9820 - 106 Street, Edmonton, AB T5K 2J6 [email protected] Keywords: soil aggregation, soil bulk density, soil moisture retention curves, soil health recovery Long-term effects of soil quality at reclaimed sites in Alberta are not well known. Observations at many reclaimed sites across Alberta indicate that soil quality problems persist resulting in reduced crop production and difficulties with land management. In 2006, a list of potential soil properties to assess (i) soil structure and soil-air-water relations; (ii) biological activity; (iii) macronutrient supply; and (iv) salinity was developed and a pilot study was conducted on an Orthic Black Chernozem near Spruce Grove, AB to assess soil quality on a physically disturbed borrow site and a control site. The objective of this poster is to present data for selecting physical soil quality indicators at this site. Cores for bulk density and bulk samples were taken from opened pits at 10 cm intervals to a depth of 70 cm. Separate samples from 0-5, 5-15 and 15-30 cm depths were taken for wet- and dry-aggregate size distribution. Undisturbed cores for moisture retention curves were obtained by inserting aluminum rings (5 cm id, 3 cm length) into soil at the three depths. Presence of roots was observed in the field. The rooting depth was 120 cm in the control soil compared to 30 cm in the disturbed soil. The bulk density of soil in the 0 to 10 cm depth (1.18 Mg/m3) was much lower than that in the physically disturbed soil (1.45 Mg/m3). Bulk density increased with depth and the mean bulk density of the control soil over a depth of 90 cm was 1.46 Mg/m3 compared to 1.72 Mg/m3 for the disturbed soil. The mean weight diameter (MWD) of dry aggregates in the 0-5 and 5-15 cm aggregates in the control soil was almost 2 to 3 fold higher compared to that in the disturbed soil. There was no difference in the 15-30 cm depth. The mean MWD for three depths was 2.66 mm in the control soil compared to 1.74 mm in the disturbed soil. The MWD of water stable aggregates in all the three soil depths in the control soil were almost 2 to 3 fold higher compared to those in the disturbed soil. The mean MWD of water stable aggregates was 1.32 mm in the control soil compared to 0.48 mm in the disturbed soil. The soil water retention at field capacity and permanent wilting point in control was higher in the control soil compared to the disturbed soil. The water storage function has been compromised in the disturbed soil and this has translated into lower crop yield which was estimated visually. The proportion of dry aggregates in fractions ranging from 12.5-8 mm to1.0-5 mm in the control soil were higher than those for the disturbed soil. In contrast, the 33.8% of the dry aggregates were in the 0.250.125 mm fraction in the disturbed soil compared to 18.2% in the control soil. Therefore, there was a higher proportion of larger dry aggregates in the control soil than in the disturbed soil. These data are consistent with the measurements obtained with bulk density. Physical differences in soil properties were still apparent after 14 years of crop production. The MWD diameter of dry and water stable aggregates have a potential of becoming sensitive indicators of soil health recovery.

Nitrogen application effects on total petroleum hydrocarbon degradation in composted drilling wastes with differed compost age WOO-JUNG CHOI1, SCOTT X. CHANG2 1

Department of Biosystems & Agricultural Engineering, Institute of Agricultural Science & Technology, Chonnam National University, Gwangju 500-757, Korea 2 Department of Renewable Resources, University of Alberta, 442 Earth Science Building, Edmonton, Alberta, Canada T6G 2E3 [email protected] Keywords: hydrocarbon contamination, white spruce, C/N ratio, drilling waste, compost Using composted hydrocarbon-contaminated wastes generated from oil and gas drilling activities as a soil amendment is considered a feasible method to dispose the wastes. The composted drilling waste can serve as a source of nutrients and organic matter. Further decomposition of residual hydrocarbon in the compost needs to be accomplished at the land application stage and N application may enhance hydrocarbon degradation by lowering the C/N ratio of the compost. The effects of N application on hydrocarbon degradation in different-aged composts (1-, 2-, 3-, and 4-year-old composts, coded as 1Y, 2Y, 3Y, and 4Y, respectively) were investigated through a laboratory incubation experiment without plants and a pot experiment planted with white spruce (Picea glauca [Moench] Voss) seedlings. During the laboratory incubation, N application significantly (P<0.05) enhanced the degradation of total petroleum hydrocarbon (TPH, C11 to C40) in the 1Y and 2Y composts that had relatively low mineral N concentrations and high C/N ratios, with the greatest effect on the 1Y compost. However, the rate of degradation of TPH in the 3Y and 4Y composts with properties contrasting the 1Y and 2Y composts was not affected by N application. In the pot experiment, N application decreased TPH concentration only in the 1Y compost. Our results from laboratory incubation and greenhouse experiments show that N application is an effective measure to enhance hydrocarbon degradation in the younger (1Y or 2Y) composts.

Effects of soil resources and light on foliar N and annual growth rates of lodgepole pine, subalpine fir, and interior spruce ERICA B. CLOSE1, RASMUS ASTRUP1 1

Bulkley Valley Centre for Natural Resources Research and Management, Box 4274, Smithers, BC, V0J2N0 [email protected]

Keywords: forest dynamics, foliar nitrogen, sub-boreal spruce zone, SORTIE-ND The relationship between understory tree growth and light has been examined extensively in BC’s forests, but less work has studied how differences in soil resources interact with light to affect understory tree growth or how tree size affects these relationships. We fit and compared height growth models for 1,102 juvenile lodgepole pine (Pinus contorta), interior spruce (Picea glauca×engelmanii), and subalpine fir (Abies lasiocarpa) trees growing in the undisturbed forest understory, and in partially and fully cut-over areas across a soil resource gradient in the Sub-boreal Spruce zone of northwest British Columbia. The percent of above-canopy light reaching the forest understory was assessed for each tree using a hemispherical canopy photograph and Gap Light Analyzer 2.0 software. We classified soil moisture and nutrient regimes according to B.C.’s Biogeoclimactic Classification System and measured height growth as the average annual height increment over the past three years. Using the multiple working hypotheses framework and maximum likelihood methods, we compared height growth models to understand the effect of soil resources and tree size on the light-growth relationship, and to understand whether species differed in their responses to light and soil resources. We also measured foliar nitrogen, leaf weight, and leaf area on every tree to gain insight into how soil resources and light interact to affect tree ecophysiological processes. Ultimately, these relationships will be incorporated into SORTIE-ND, a spatially explicit stand dynamics model, and used to predict forest regeneration after mountain pine beetle attack.

Soil development as a function of air temperature, vegetation cover and permafrost distribution, Keno Hill area, central Yukon M.M. COTE1, C.R. BURN2, C.A.S. SMITH3 1

Department of Geography and Environmental Studies, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada. Present address: Geological Survey of Canada – Pacific Division, 9860 West Saanich Road, Sidney, BC V8L 4B2, Canada; 2 Department of Geography and Environmental Studies, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada; 3 Agriculture and Agri-Food Canada, Box 5000, Summerland, BC, V0H 1Z0, Canada. [email protected] Keywords: discontinuous permafrost, atmospheric temperature inversions, topographic effects, Keno, Yukon. In the dissected terrain of central Yukon, atmospheric temperature inversions lead to little difference in annual mean air temperature between sites on summits and in valley bottoms. Therefore, altitudinal distribution of discontinuous permafrost depends on microclimatic factors driven by variations in slope and aspect, which control the receipt of solar radiation. A transect of eleven sites was established near Keno, YT, to measure air and near-surface ground (soil) temperatures on the north- and southfacing slopes of Lightning Creek. Below tree line, annual potential solar radiation received at the ground surface varied by a factor of 3.5 due to topographic and canopy effects. Soil moisture varied with potential radiation, so that north-facing slopes were associated with Cryosols and a thick surface organic horizon, in comparison with Brunisols and a thin, patchy organic layer on south-facing aspects. Vegetation altered snow conditions, so that a thin snow pack was characteristic above tree line, but great depths accumulated in tall shrubs that comprise the subalpine zone. In combination, these conditions ensure the absence of permafrost from south-facing slopes at locations where the soil is dry and has only a thin organic horizon, but otherwise, perennially frozen ground is ubiquitous in valley bottoms, above tree line, and on north-facing aspects. During the period of observation, the warmest annual mean ground temperature at 50 cm depth (2.1°C) occurred in mid-slope, south-facing Brunisols. Equivalent north-facing soils had annual mean temperatures ranging from -0.5 to -1.6°C.

Pedological observations from the 2007 Okanagan Agricultural Soil Study ERYNE CROQUET, ELIZABETH KENNEY National Land and Water Information Service, Agriculture and Agri-Food Canada 6947 #7 Highway, PO Box 1000, Agassiz, BC, V0M 1A0 [email protected] Keywords: agricultural soils, B-horizon, pedon, anthropedogenic The 2007 Okanagan Agricultural Soil Study was an intensive study of agricultural soils in the Okanagan and Similkameen Valleys. One component of the study involved describing and sampling pedons for inclusion into the National Pedon Database of the Canadian Soil Information System (CanSIS). Three excavations at 56 sites yielded 48 complete pedon descriptions and 120 partial descriptions. The soils examined had more B-horizon development than was recorded in the existing published soil surveys for the region. A possible cause for this enhanced development may be agricultural practices, particularly irrigation. Another significant observation was mechanical mixing of A and B-horizons, with distinct rip marks at the lower boundary. The Canadian System of Soil Classification (CSSC) does not have enough flexibility to describe these anthropedogenic horizons. Currently, all anthropedogenic soil horizons are named either Ap, if mineral, or Op, if organic. The CSSC does not consider anthropogenic horizons when classifying soils to any level of the hierarchy. Anthropedogenic soils should be included in the CSSC and a systematic method for naming and describing anthropedogenic horizons should be developed. Reference List Gough, N. A., Hughes-Games, G. A. and Nikkel, D. C. 1994. Soil Management Handbook for the Okanagan and Similkameen Valleys. Victoria: BC Ministry of Agriculture, Fisheries and Food. Soil Classification Working Group 1998. The Canadian system of soil classification (3rd edition). Publication 1646. Agriculture and Agri-Food Canada. Sprout, P. N. and Kelley, C. C. 1960. Soil Survey of the North Okanagan Valley. Interim Report. Kelowna: British Columbia Department of Agriculture. Wittneben, U. 1986. Soils of the North Okanagan Area. Victoria: Ministry of the Environment Wittneben, U. 1986. Soils of the Okanagan and Similkameen Valleys. MOE Technical Report 18. Report 52 of the British Columbia Soil Survey. Victoria: Ministry of the Environment.

The impact of simulated climate change on soil nutrient supply rates in transition mixedwood-boreal forest ecosystems of Québec ANNA DABROS*1, JIM FYLES1, BOBBI NASH2 1

Department of Natural Resource Sciences, McGill University, Montréal, QB Western Ag Innovations, Inc., Saskatoon, SK [email protected]

2

Keywords: climate change, disturbance, litter decomposition, PRSTM-probes, nutrient supply rates Trembling aspen (Populus tremuloides) populations in northwestern Québec are regenerating or persisting more frequently than ever before, especially at sites previously dominated by black spruce (Picea mariana). Soil nutrient availability is one of the main factors affecting forest regeneration after disturbance. A warming climate has the potential to impact microbial processes and as such, decomposition rates which affect nutrient availability. A warming treatment was applied to explore the potential impact of climatic changes on nutrient supply rates, decomposition processes, and ultimately, on growth and performance of north-advancing trembling aspen and black spruce after fire and logging disturbances in the transitional mixed-wood boreal zone in northwestern Quebec. Soil nutrient supply rates (determined using PRSTM-probes) and decomposition rates of aspen dominated, black spruce dominated and Sphagnum litter types were measured in response to open-top chamber (OTC) simulated warming in the presence or absence of Sphagnum moss substrate, under three disturbance types. In the presence of Sphagnum at the logging site, the supply rates of Ca2+ and Mg2+ were significantly lower in response to warming. Also, N supply rates from the control plots at the logging site were found to be significantly higher than at any other combination of the warming treatment and disturbance type. In terms of the effect of the warming treatment on litter decomposition, the aspen litter decomposition rates were lower inside the OTCs, related to the warming treatment as well as soil nutrient supplies. The results suggest that the impact of the potential climatic changes on the soil system are likely to induce a complex net of interacting effects on soil nutrient supply rates and decomposition processes, which may ultimately affect the regeneration and growth of aspen and black spruce. This may lead to potential shifts in plant species composition, and change the relative abundance of deciduous and coniferous trees in the transitional mixedwood-boreal zones of Québec.

Risk of agricultural contaminant transport by crack flow in Canada HUMAIRA DADFAR1, SUZANNE E. ALLAIRE2, REINDER DE JONG3, ERIC VAN BOCHOVE1, JEAN-THOMAS DENAULT1, GEORGE THÉRIAULT1 1

Agriculture and Agri-Food Canada, Québec, QC Horticultural Research Center, Université Laval, Québec, QC 3 Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, ON [email protected] 2

Keywords: IROWC, macropore flow, movement of contaminants, preferential flow, risk indicators Indicators of risk of water contamination by nitrogen, phosphorus, pathogens and pesticides are components of the National Agri-Environmental Health Analysis and Reporting Program (NAHARP) initiated by Agriculture and Agri-Food Canada (AAFC) to address various environmental policy needs. Crack flow (CF) is one of the four preferential flow aspects of the connectivity algorithm for calculating risk indicators of contaminant transport such as phosphorus and coliforms (IROWC-P and IROWC-coliform) from agricultural land to surface waters. Crack flow predicts the likelihood of preferential contaminant transport through cracks at the Soil Landscape of Canada (SLC) polygon scale (1: 1,000,000) across Canada. It is not intended as a quantitative measure of contaminant transport. Crack flow is preferential movement along continuous cracks through an unsaturated soil matrix. Cracks develop when there is heterogeneity in soil water distribution, and occur during a drying process of certain duration in soils with significant clay content (Jarvis 2007; Hendrickx and Flury 2001). Several factors influence the significance of crack formation, including: 1) soil texture (clay content); 2) number of soil water deficit/drying days; 3) tile drainage, by increasing heterogeneity of water distribution; and 4) crops, due to heterogeneous water extraction. Once the cracks are formed, then surface runoff has to occur so that flow into the cracks takes place. The data sources to estimate crack flow include the National Soil Layer File and National Component Table (Soil Landscapes of Canada Working Group 2007), Census of Agriculture (1981-2006) data, weather data (1975-2006) from AAFC’s Ecodistrict climate database (1:7,500,000 map scale), output from the Versatile Soil Moisture Budget model (VSMB; Akinremi 1996), and tile drainage data provided by provincial and federal experts. The distribution of the likelihood of CF in agricultural SLC polygons across Canada will be presented along with sensitivity analysis, advantages and limitations of the CF subcomponent of IROWC. Reference List Akinremi, O. O., McGinn, S.M. and Barr, A. G. 1996. Simulation of soil moisture and other components of the hydrological cycle using a water budget approach. Can. J. Soil Sci. 76: 133-142. Hendrickx, J. M. H. and Flury, M. 2001. Uniform and preferential flow mechanisms in the vadose zone. Pages 149-187 in Conceptual Models of Flow and Transport in the Fractured Vadose Zone. Edited by National Research Council, National Academy Press, Washington DC. Jarvis, N. J. 2007. A review of non-equilibrium water flow and solute transport in soil macropores: principles, controlling factors and consequences for water quality. Eur. J. Soil Sci. 58:523-546. Soil Landscapes of Canada Working Group. 2007. Soil Landscapes of Canada v3.1.1 Agriculture and Agri-Food Canada. (digital map and database at 1:1 million scale). [Online] Available: http://sis.agr.gc.ca/cansis/nsdb/slc/v3.1.1/zip_files/index.html [2007 Aug26].

Aggregate stability-energy relationship determined by a combination of ultrasound, wet sieving and turbidity DARYL DAGESSE1, AMANDA ANGER1 1

Brock University – Geography Dept., St. Catharines, Ont, L2S 3A1 [email protected]

Keywords: ultrasound, aggregate stability, turbidity Soils exhibiting greater structural stability are better able to retain a particular arrangement of solids and voids when exposed to different stresses. These stresses may be naturally occurring, such as raindrop impact or the result of freezing and thawing, or may be anthropogenic in nature, resulting from management practices including tillage (Kay and Dexter, 1990). The detrimental effects of structural deterioration include pore clogging and surface crust formation, but the breakdown of large soil clods or the amelioration of a compacted soil may be an intentional management goal. Aggregate stability is thus an important property with respect to soil management. The combination of the stability of macroaggregates (>250µm), characterized by Wet Aggregate Stability (WAS), and the amount of clay that disperses, referred to as Dispersible Clay (DC), as a result of an energy input to the soil, is a useful measure of aggregate stability (Tisdall and Oades, 1982). A stability measurement procedure using this combination of WAS and DC was proposed by Pojasok and Kay (1990). A limitation of this method is the lack of quantification of the energy input. The application of ultrasonic energy to soil suspensions has long been used to facilitate complete dispersion of the soil for further physical and chemical measurements (e.g., Edwards and Bremner, 1964). This method of soil dispersion for aggregate stability measurement procedures has the advantage of being both controllable and quantifiable, thus facilitating the establishment of the dispersion versus energy input relationship for a given soil (Fuller and Goh, 1992; Raine and So, 1993). The combination of the application of ultrasonic energy and resultant WAS and DC is investigated as a rapid method of establishing the aggregate stability versus energy relationship for soils of differing texture. Reference List Edwards, A.P. and Bremner, J.M., 1964. Use of sonic vibration for separation of soil particles. Can. J. Soil Sci. 44: 366. Fuller, L.G. and Goh, T.B., 1992. Stability-energy relationships and their application to aggregation studies. Can. J. Soil Sci. 72: 453-466. Kay, B.D and Dexter, A.R., 1990. Influence of aggregate diameter, surface area and antecedent water content on the dispersibility of clay. Can. J. Soil Sci. 70: 665-671. Pojasok, T. and Kay, B.D., 1990. Assessment of a combination of wet sieving and turbidimetry to characterize the structural stability of moist aggregates. Can. J. Soil Sci. 70: 33-42. Tisdall, J.M. and Oades, J.M., 1982. Organic matter and water-stable aggregates in soil. J. Soil Sci. 33: 141-163. Raine, S.R. and So, H.B., 1993. An energy based parameter for the assessment of aggregate bond energy. J. Soil Sci. 44: 249-259.

Freezing induced volume changes in clay soils DARYL DAGESSE1 1

Brock University – Geography Dept., St. Catharines, Ont, L2S 3A1 [email protected]

Keywords: freezing, clay, volume change An increased soil volume is usually associated with soil freezing as a direct result of the 9% volumetric expansion of water as it freezes to ice. This assertion is predicated on the assumption that the soil is close to saturation at the time of freezing, although this is not necessarily always true in the field. The literature contains numerous references to freezing induced shrinkage of fine grained soils upon freezing (e.g., Kay and Angers, 2002). Hamilton (1966) presented a comprehensive data set of freezing induced volume changes for soils of varying clay contents. A previous presentation (Groenevelt and Dagesse, 2005) considered the thermodynamic basis of this phenomenon. The present study further investigates this phenomenon. While Hamilton (1966) used soils compacted from a disturbed state, undisturbed cores of soils from different textural classes are also used with the aim of investigating the relationship between volume change, void ratio, ice content and ice pressure resulting from soil freezing.

Reference List Groenevelt, P.H. and Dagesse, D.F., 2005. Bulk volume change upon freezing of soil. Joint Meeting of the Geological Association of Canada, the Mineralogical Association of Canada, the Canadian Society of Petroleum Geologists and the Canadian Society of Soil Sciences. May 15-18, 2005. Studley Campus of Dalhousie University, Halifax, Nova Scotia. Hamilton, A.B., 1966. Freezing shrinkage in compacted clays. Can. Geotech. J. 3: 1-17. Kay, B.D. and Angers, D.A., 2002. Soil Structure. Pages 249-295 in A.W. Warrick ed.Soil Physics Companion. CRC Press LLC, Boca Raton, FL.

Extractable acid-soluble copper in cultivated copper-mine tailings ARNAUD S. DE CONINCK*1, ANTOINE KARAM1, LOTFI KHIARI1, ALFRED JAOUICH2 1

Équipe de Recherche en Sols Agricoles et Miniers, Department of soils and agrifood engineering Laval University, Quebec, Canada; 2 Department of Earth and Atmospheric Sciences, University of Quebec at Montreal, Quebec, Canada. [email protected] Keywords: Cu speciation, maize, acetic acid, mine tailing In the present study, the acid-soluble copper (Cu) of Cu-mine tailings amended with peat-moss and shrimp wastes compost and cultivated with maize (Zea mays L.) is assessed using chemical extractants of 0.1 M acetic acid (HAc) and Mehlich-3. Unbuferred HAc has the ability to dissolve carbonate particles and to extract ‘specifically bound’ or ‘specifically adsorbed’ trace metals. Mehlich-3 solution (Mehlich, 1984), composed of 0.2 M CH3COOH (HAc) 0.25 M NH4NO3, 0.015 M NH4F, 0.013 M HNO3 and 0.001 M ethylene diamine tetraacetic acid (EDTA) has the ability to extract occluded Cu, organically bound Cu fraction, and soluble, exchangeable and specifically adsorbed Cu fractions. The extractable Cu concentration for a single HAc extraction ranged between 2.7 and 40.2 mg kg−1 and between 21.9 and 78.4 mg kg−1 for 10 successive HAc extractions. As a percentage of total phytoavailable Cu, the acid-soluble fraction of Cu for HAc (one extraction) averaged 27.0% (range: 4.3-47.0%). The percentage of acid-extractable Cu for Mehlich-3 was 46.3% (range: 31.3-72.6%). Mehlich-3 extractant desorbed about 1.2 to 8 times more Cu than a single HAc extraction. This result indicates that Mehlich-3 extractant is more effective at mobilizing Cu from cultivated tailing than a single extraction with 0.1 M HAc. Inversely, the sum of the amounts of Cu extracted by ten successive extractions with 0.1 M HAc was 1.4-fold than Mehlich-3 extractable Cu. However, both extractants are unable to completely extract the total phytoavailable Cu fraction despite the significant correlation found between the total phytoavailable Cu content and both CuHAc (r = 0.791, P < 0.001) and CuMehlich3 (r = 0.755, P < 0.001). The results obtained suggest that peat containing compost is expected to lower the extractable acid-soluble Cu fraction in the cultivated tailing.

Gyttja: A major parent material for Prairie wetland soils CHRISTIAN DEDZOE*1, FRAN WALLEY1, AND DAN PENNOCK1 1

Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 [email protected] Keywords: wetlands, salinity, hydrology, Gleysol

The horizon sequence of depressional soils of the Prairie Pothole region commonly includes a layer of silty clay textured material that has thin (2-5 mm) horizontal beds or plates. This layer can be up to 1.5 m thick and is found as both a near-surface soil horizon and at depth in paleosols. The material can undergo a major colour change from a black (10YR 2/1) colour upon initial exposure to the atmosphere to white or light gray (10 YR 7/1 to 10YR 8/1) colour after several hours of exposure. The base of the layer in several locations contains shells (indicating that it is a post-glacial deposit) and it can overlay several different types of glacial sediment. Examples from several locations in the Prairies will be used to illustrate the range of properties of this layer. Wetland scientists readily identify this material as gyttja and it probably would fit the diatomaceous

earth class of limnic material under the Organic horizons section of the Canadian System of Soil Classification. In the CSSC these horizons are assigned a C horizon with no suffix and hence become indistinguishable from other mineral C horizons despite their vastly different origin. Moreover where a thin layer of this horizon directly overlies a clay loam B horizon they can be readily misinterpreted as an Aeg overlying a Btg and misclassified as a Luvic Gleysol. In positions where the gyttja layer is thick and it is overlain by only an A horizon the horizon sequence is Ah/C, and classifying the soil as an Orthic or Humic Regosol is an unsatisfactory placement of this wetland soil in the Canadian System of Soil Classification.

Snow, soils, and climate STEPHEN J. DÉRY1 1

Environmental Science and Engineering Program, UNBC, 3333 University Way, Prince George, BC. [email protected]

Keywords: snow, soil moisture, soil thermodynamics, climate memory, climate change

Snow and soils, with their distinctive physical properties, form key components of the global climate system. Both snow and soils compose important reservoirs for freshwater that can impact river runoff, water resources, and the risk of floods and droughts. These surfaces also greatly influence the surface radiation and energy budgets that control near-surface air temperatures. This talk will therefore focus on the links between snow, soils and climate with an emphasis on western Canada. A review of some of the physical characteristics of snow and soils will first be introduced. The relationship between snow and soil thermodynamics will then be broached, followed by a discussion of the role of snowmelt on replenishing soil moisture. This will lead to the introduction of “climate memory” in the regional and global climate system. In many land surface areas, climate memory arises from anomalies in snow accumulation that persist as soil moisture and thermal anomalies, leading to continental-scale impacts on climate. The talk will close with a brief summary of the Intergovernmental Panel on Climate Change (IPCC 2007) 4th assessment report (AR4), with a focus on 21st century projected changes in air temperature, precipitation and snow for western Canada. This talk will therefore provide insights on the contemporary and potential future roles of snow and soils on regional and global climate.

Long-term warming alters arctic soil microbial community structure 1*

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J.R. DESLIPPE , M. HARTMANN , E.G. FARRELL , W.W. MOHN , AND S.W. SIMARD

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1

Department of Forest Science and 2Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada. [email protected]

Keywords: climate change, arctic, fungi, bacteria, rRNA genes Currently the western North American Arctic is experiencing the fastest rate of warming in the world. Climate warming in the region has been up to 0.1oC per year over the last thirty-five years (IPCC 4) highlighting the relevance of Polar Regions as sensitive indicators of global climate trends. Although much effort has been directed toward understanding biological responses to climate change, we still know little about the effects of warming on the structure and activity of soil microbial communities, which are important drivers of the earth’s carbon and nutrient cycles. Work in alpine tundra suggests that seasonal cycles may have strong impacts on the structure of soil communities, raising the question of whether warming leads to changing taxa and assemblages or merely accelerated seasonal activity of certain microbial groups in arctic tundra soils. In June, July and August of 2006 and 2007, we collected soils treated with warming by greenhouses since 1989 that are maintained as part of the Arctic Long-term Ecological Research (LTER) site at Toolik Lake, AK (68o38’N, 149o34’W). DNA was extracted from organic and mineral soil horizons. We used Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis of 16S rRNA to profile the bacterial community. Similarly, we used Automated Ribosomal Intergenic Spacer Analysis (ARISA) of the Internal Transcribed Spacer (ITS) region of 18S rRNA to profile the fungal community. Non-metric Multidimensional Scaling ordination analyses of these data revealed that soil warming results in shifts in the community structure of bacteria and fungi from organic and mineral soils that are far greater than those due to normal seasonal variation. To further characterize this change in fungal community structure, we pooled DNA from warmed and control soils in organic and mineral soil layers and performed Ribosomal Intergenic Spacer Analysis (RISA). Key phylotypes were selected for DNA sequencing, which allowed for identification of the fungi that changed in response to the warming treatment.

Evaluation of aggregate and dispersed retention harvesting to retain soil enzyme activities MEILIANA DEWI* and SUE J. GRAYSTON Department of Forest Sciences University of British Columbia 2424 Main Mall Vancouver, BC V6T 1Z4 [email protected] Keywords: variable retention, partial harvesting, soil enzymes, soil microorganisms Variable retention harvesting has been increasingly adopted as an alternative to clearcutting in British Columbia. Variable retention is a type of partial harvesting in which patches of live trees of various patterns and densities are left standing on harvested sites. This study examines two broad categories of variable retention harvesting, aggregate and dispersed retention, for their potential in maintaining soil enzyme activities after harvesting. Extracellular soil enzymes play a key role in nutrient cycling because they catalyze processes that degrade complex organic compounds to release plant-available nutrients in the forest soil. Harvesting may affect enzyme activities as it modifies soil physicochemical characteristics and the soil microbes responsible for much of the enzyme production. However, variable retention harvesting may be able to reduce the impacts of clearcutting to the soil environment as the retained trees provide continuous supply of energy in forms of litter input and root exudates. Soil samples were collected five years after harvest from the STEMS installation, a second growth even-aged Douglas-fir/western hemlock/western redcedar forest in the coastal western hemlock (CWH) biogeoclimatic zone located in the Snowden Demonstration Forest near Campbell River, Vancouver Island. The treatment blocks being studied are the aggregated and the dispersed retention treatments, as well as the clearcut and uncut areas. The activities of β-glucosidase, N-acetylglucosaminidase, phosphatase, phenol oxidase, and peroxidase were measured by performing enzyme assays on soil samples collected from four random locations in the clearcut and control plot; from the centre, edge and 10 m, 20 m, and 30 m along a northerly transect from the edge of four replicate 0.2 ha tree patches in the aggregate retention plot; and from beside the tree and 10 m, 20 m, 30 m along a northerly transect from four replicate trees in the dispersed retention plot. Five years after harvest, the effects of harvesting could still be detected through enzyme assays. The clearcut plot was found to have the lowest enzyme activities. In addition, the dispersed retention plot had more similar enzyme activities across the treatment compared to the aggregate retention plot, where enzyme activities decreased with increasing distance from the retention trees. Dispersed retention appears better than aggregated retention in maintaining soil enzyme activities closer to the uncut conditions across the harvested site.

An evaluation of the relationship between microbial diversity and soil function restoration in peat using a constructive approach PEDRO A. DIMITRIU1, DAVID LEE*1, CINDY E. PRESCOTT1, SYLVIE QUIDEAU2, SUE. J. GRAYSTON1 1

Univ. of British Columbia, Vancouver, BC Univ. of Alberta, Edmonton, AB [email protected]

2

Keywords: .microbial diversity, function, respiration, enzyme activities Our current knowledge on the relevance of microbial diversity for the recovery and maintenance of soil biological processes is rudimentary. We examined the hypothesis that bacterial diversity would have a key role in reestablishing soil function after a major disturbance; we also asked whether this effect would depend on the inoculum source. Sterile sedge and fibric peat samples were re-inoculated with a 10-1, 10-3, 10-5, or 10-8 dilution of either the same or reciprocal peats. After 5 months incubation to allow for biomass stabilization, the extreme dilution levels were exposed to a nucleotide analog that labels active DNA. The bacterial community structure of all treatments was assessed by PCR-DGGE, whereas function was determined by measuring respiration and the activities of hydrolytic and oxidative enzymes.. Both the resulting community structure and the soil respiration profiles depended on the source of inoculum rather than the recipient soil; the enzyme activity patterns depended mainly on the soil type. A general decline in band numbers with increasing dilution level was positively correlated (R2 = 0.71-0.95) to soil respiration rates. The richness of the active bacteria tended to be higher than total richness, and was independent of dilution level. We propose that the relationship between soil function and diversity is not only related to the taxonomic breadth of the function being performed, but also depends on whether the dynamics of bacterial recolonization is structured by interactions between the inoculum source and the nature of the substrate it colonizes.

Changes in the residual soil nitrogen levels and N losses through drainage in Canadian soils over the last 25 years CRAIG F. DRURY1, JINGYI .Y. YANG1, REINDER De JONG2, XUEMING M. YANG1, E. (TED) C. HUFFMAN2 and KEITH REID3 1

Agriculture & Agri-Food Canada, Harrow Ontario, N0R 1GO Agriculture & Agri-Food Canada, Ottawa, Ontario, Canada K1A 0C6 3 Ontario Ministry of Agriculture Food and Rural Affairs, Stratford, Ontario, Canada N5A 5T8 [email protected] 2

Keywords: nitrate loss, water quality, agri-environmental indicator Residual soil nitrogen (RSN) is the amount of inorganic nitrogen that remains in the soil at the end of the growing season after crops have been harvested. RSN can be estimated as the difference between all N inputs (fertilizer, manure-N, biological fixation, and atmospheric deposition) and all N outputs (N removed in crop harvest, N lost from ammonia volatilization and N lost from denitrification). RSN was calculated on a regional scale as well as on a provincial and national level from 1981 to 2006. The Canadian average RSN values steadily increased steadily from 9.3 to 15.5 kg N/ha (67 % increase) from 1981 until 1996 and then to 25.0 kg N/ha (61% increase) by 2001. The RSN values decreased to 17.7 kg N/ha in 2006. The spike in RSN values in 2001 was due to a combination of factors including low crop yields as a result of drought conditions in many parts of Canada in the summer of 2001 as well as an increase in legume crop acreages which contributed to large N inputs (fixation of atmospheric N) without a corresponding decrease in either fertilizer or manure inputs. In Ontario, the RSN estimate was greater than all other provinces in 1981 at 42.2 kg N/ha which was over 4 times the Canadian average (9.3 kg N/ha). These levels were high as a result of the increased amount of N added to Ontario soils through fertilizer, manure and nitrogen fixation in the highly productive regions in Eastern Canada. RSN levels remained fairly steady over the 6 census years except for 2001 when the RSN level reached 59.9 kg N/ha due to low N uptake under drought conditions and an increase in legume acreage. The amount and concentration of N lost through leaching (IROWC-N) after harvest is dependent upon the RSN levels and the water budget (antecedent soil moisture content, precipitation, evaporation and surface runoff). We estimated that nationally both N lost due to leaching and the N concentration in the drainage water increased steadily from 1981 to 2006 (from 2.1 to 2.6 kg N/ha for N lost and from 2.2 to 5.3 mg N/L for N concentration), primarily due to increasing RSN levels. In Ontario, the amount of N lost remained fairly constant over the 25 years with a range of 14.4 kg N/ha in 1981 to 17.6 kg N/ha in 1991, while N concentration in the drainage water ranged from 8.4 mg N/L in 1981 to 9.6 mg N/L in 2001. These environmental indicators (RSN and IROWC-N) provide a tool to identify high risk areas to N leaching in Canada and upon field validation, to identify where best management practices could be used to reduce nitrate loss to the environment.

Cover crops and water management for reducing nitrate leaching losses from agricultural soils CRAIG F. DRURY, CHIN S. TAN, W. DANIEL REYNOLDS, THOMAS W. WELACKY, THOMAS O. OLOYA, TIEQUAN ZHANG, JOHN D. GAYNOR Agriculture & Agri-Food Canada, Harrow, Ontario, Canada N0R 1G0 [email protected] Keywords: controlled tile drainage – subirrigation, cover crop, nitrate leaching, surface runoff Nitrate leached from agricultural soils can be both an environmental concern when it enters rivers and lakes, and a human health concern when it enters aquifers used for potable water. Management practices such as cover crops and controlled tile drainage – subirrigation (CDS) have been identified as possible ways to reduce nitrate losses. A 6-yr study (1999-2005) was conducted in Southwestern Ontario in which the effectiveness of a winter wheat cover crop and CDS were assessed for a cornsoybean rotation. The four treatments included: cover crop with and without traditional tile drainage (DR), and cover crop with and without CDS. Corn received 15 kg N ha-1 at planting and 150 kg N ha1 as a sidedress application at the 6 leaf stage. No fertilizer N was applied to soybean. Surface runoff and tile drainage water were collected using autosamplers and analyzed for nitrate-N. Relative to no cover crop, winter wheat reduced surface runoff by 10.9% and increased tile drainage by 8.2% for DR; and it reduced surface runoff by 29.4% and increased tile drainage by 35% for CDS. The flow weighted mean (FWM) nitrate concentration in tile drainage from the DR treatment was 9.29 mg N L-1 and this was reduced by 19.5% when the cover crop was planted (7.48 mg N L-1). The CDS system reduced FWM nitrate concentrations in tile drainage by 15.5% (7.85 mg N L-1) compared to DR. However when both the cover crop and CDS were used, the FWM nitrate concentrations (5.01 mg N L-1) were 46% lower than those obtained using no cover crop and DR. The 6-yr cumulative nitrate loss with the DR treatment (101 kg N ha-1) was reduced by 12% with cover crops (89.1 kg N ha-1) and by 37.5% with the CDS system (63.3 kg N ha-1) whereas when both cover crops and CDS were used, cumulative nitrate loss was reduced by 46.7% to 53.9 kg N ha-1. Although the cover crop assimilated residual N in the soil profile, this benefit is partially offset by increased tile flow. Hence both a cover crop and CDS can effectively reduce nitrate losses from agricultural soils, and they are particularly effective when used in combination.

Cutblock-level soils monitoring in British Columbia STÉPHANE DUBÉ BC Ministry of Forests and Range, NIFR, 1011 4th Ave, Prince George, BC, V2L 3H9 [email protected] Keywords: Soil conservation, monitoring, indicators, forest activities The objective of the Forest and Range Evaluation Program or FREP (http://www.for.gov.bc.ca/hfp/frep/) is to determine whether current forest and range practices and policies meet government’s objectives for the soil resources identified in Forest and Range Practices Act of BC (FRPA). The objectives set by government for soils are, without reducing the supply of timber from British Columbia’s forests, to conserve the productivity and the hydrologic function of soils. Through resource stewardship monitoring of soils after forest management activities, we can monitor the effectiveness of government policy, legislation, practices, plans and standards in protecting soils in BC. A protocol for data collection has been developed by the Soils Team of the BC Ministry of Forests and Range (Shannon Berch, Chuck Bulmer, Bill Chapman, Paul Courtin, Mike Curran, Sandy Currie, Stéphane Dubé, Graeme Hope, Richard Kabzems and Marty Kranabetter) for evaluation of the soil value at the cutblock-level. The protocol consists of ground and image based methods that consider soil disturbance observable on the ground as a proxy for longer-term effects. The methods include indicators that are assessed through visual surveys and remote sensing on recently harvested areas and provide an assessment of government objectives for the soil value. A protocol document has been created to provide background information and instructions for data collection (http://www.for.gov.bc.ca/hfp/frep/site_files/indicators/Indicators-Soils-Protocol-2007.pdf) Over the last three years, Pilot testing of the Cutblock-level Soils Resource Stewardship Monitoring Protocol has been conducted in some areas of BC. First results showed loss of productivity due to access structure amounted to 3.3% of gross block area, which was below the soil allowance of 7% for this category of soil disturbance reflecting the shift from landing-based operations to roadside work areas. This is not without its problems, however. Soil disturbance levels created during roadside processing of timber and piling debris were often inordinately concentrated and exceeding FRPA standards. In salvage-logged beetle areas, changes in soil hydrologic functions were important as evidenced by exposed seepage areas and areas of water ponding. In the remaining areas to be reforested, most cutblocks were achieving prescribed soil limits for counted disturbance of 5% for sensitive soils and 10% on other soils. Counted soil disturbance averaged 6% of the net block area whereas total disturbance (i.e., any evidence of machine traffic) averaged 20% but reached over 70% on a sensitive site. This suggested that some soils were not correctly identified and therefore failing one of the underlying assumptions of FRPA. Forest practitioners should remain vigilant in the face of soil hydrological response to the forest activities in beetle salvaged-areas. Although sample size was not large, these results closely reflected field observations made by specialists and forest practitioners, and provided reliable information on the status of the forest soil resource in BC.

The soil-landscape paradigm and hydrology MILES F. DYCK*1, R. GARY KACHANOSKI1, SHELLEY A. WOODS2 1

Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3 Alberta Agriculture and Food Agriculture Center, Lethbridge, AB T1J 4V6 [email protected] 2

Keywords: soil survey, soil classification, soil water balance, vadose zone hydrology, tillage erosion The soil landscape-paradigm, as presented by Hudson (1992), has its roots in Jenny’s soil forming factor equation: SOIL = f(Climate, Organisms, Relief, Parent material, Time, Human activities). Genetic soil classification systems such as the Canadian system state that, during pedogenesis, the five factors interact to form the soil profile (pedon). Essentially, the soil landscape paradigm states that the spatial distribution soil profiles are a result of spatial variations in the interactions between the soil forming factors. The pedon, catena, and soil landscape unit are thus meant to be representative of the spatial variations in the interactions between the soil forming factors at different spatial scales. Soil maps, therefore, not only contain information about the spatial distribution of soils, but are also thought to contain information about the spatial variability of the soil forming factors. Although soil scientists recognize that the interactions between the soil forming factors likely change with time, it is more difficult to resolve these temporal changes using the soil-landscape paradigm. Often it is assumed that there is very little or no temporal variations in the soil forming factors during soil genesis. With the exception of paleosols, temporal changes in the soil forming factors can not usually be distinguished by visual observation of a soil profile. Indeed, it is unclear how long it takes changes in soil forming factors to show up as changes in soil morphology, or how these temporal changes can be represented in a soil classification system. It can be shown that the soil forming factors are connected with hydrology and the soil water balance in some way. In this presentation, examples will be given showing how temporal changes in soil water balance at the pedon, catena and landscape scale make it difficult to apply soil survey information to hydrological problems. Discussion will also focus on possible feedbacks between soil horizon formation and soil hydrology. The general conclusion is that temporal changes in soil forming factors are not well represented in the Canadian System of Soil Classification. Future amendments to the Canadian System should explicitly recognize temporal changes in soil forming factors. Reference List Hudson, B. D. 1992. The soil survey as paradigm-based science. Soil Sci. Am. J. 56: 836-841.

Assessment of reclamation success of well sites and pipelines on native grasslands in Rumsey Block, a protected area in central Alberta MAE E. ELSINGER*1, M ANNE NAETH1 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta [email protected]

Keywords: reclamation, restoration, native prairie, prairie soil The Rumsey Block is a 183 km2 protected area in central Alberta that lies on the border of the Central Parkland and Northern Fescue Natural Subregions. Although oil and gas extraction is still a permitted land use on this public land, a policy has been in place since at least the early 1980s for these disturbances to be restored to native prairie. Three objectives of the present study are to determine if the native prairie soil and plant community conditions have been restored on past well site and pipeline disturbances, how these disturbances can be characterized by soil and plant community properties and what construction and reclamation techniques have led to success or failure of restoration efforts on these sites. In 2006 and 2007 data on soil chemistry, fertility and bulk density and plant cover and composition were collected on 33 well sites and 17 pipelines ranging in date of construction from 1967 to 2004. Data were collected on adjacent undisturbed areas for comparison to the disturbances. Differences in soil and plant community characteristics between oil and gas disturbances and their undisturbed references will be presented. Relationships of soil characteristics such as pH, electrical conductivity, carbon and nitrogen content, and bulk density to ground cover and abundance of key plant species will also be explored. Soil and plant community characteristics will be linked to construction and revegetation techniques and age.

Effect of urea fertilizer placement on N2O production from a silt loam soil RICHARD ENGEL1, DONGLI LIANG2, ASHELY BEMBENEK1, AND ROSIE WALLANDER1 1

Dept. of Land Resources and Environ. Sci., Montana State Univ., 334 Leon Johnson Hall, P.O. Box 173120, Bozeman, MT 59717-3120 2 College of Resources and Environment, Northwest A & F University, Shaanxi, Yangling, China, 712100 [email protected] Keywords: broadcast, band, nest

Urea (46-0-0) placement in band or nests has been shown to enhance nitrogen use efficiency, but limited work has been done to assess its effect on N2O production. This study compared N2O production from urea prills applied to a silt loam soil using different placements. Experiment I was conducted (48 d) in greenhouse pots (6.3 kg soil). Urea (0.59 g N) was applied as broadcast surface (bcs), broadcast incorporated (bci), band, and nest placements. Experiment II was conducted (201 d) in the field and included urea bcs, band, and nest placements at 100 and 200 kg N ha-1. In Experiment I, bci and bcs emissions rose to a peak and returned to background levels in advance of band and nest placements. Nitrous oxide production was prolonged for the band, and in particular the nest placement. The fraction of urea loss as N2O was estimated to be 0.11%, 0.14%, 0.20%, and 0.26% for the bci, bcs, band, and nest placements, respectively. Experiment II results were generally consistent with Experiment I, though emissions were quite variable and impacted by summer drought. Nest emissions lagged behind bcs and band applications as result of inhibition of urea hydrolysis and nitrification, particularly at the high N rate. Nitrous oxide losses were estimated to be 0.16, 0.66, and 0.60% of applied N for bcs, band, and nest placements, respectively. Cumulative N2O emissions and fertilizer loss coefficients appear to be enhanced by placement of urea prills in small, concentrated zones.

Evaluating ion pairs effects on Iranian salty and sodium soils ALLAHYARIPOUR FOROUGH1, EBRAHIM PAZIRA2 1 2

Graduate of Islamic Azad University Research and Science Branch Professors of Islamic Azad University Research and Science Branch

[email protected] Keywords: ion pairs, sodium adsorption ratio, salt, soils Nowadays, soil salty and alkali (means continental sodium) and its resulted problems is and prohibitive aspect of land exploration in many continents especially in dry and half-dry areas, so it is as most bottleneck cause in irrigation agriculture. Because of geographical position and climates, Iran has most extended soils affected by solution additives and it is fifth country in the world for this which located in central continental, southern fields. In our country, rare studies taken place in many aspects especially for soil different parameters relations affected by salt, so in this ground it is used from other countries conditions. In this study, we have planned to evaluate part of KHOZESTAN province lands which has heavy alkali and salty soils comprehensively and offer new practical relations and evaluate some present relations. In this extent, this study estimated anionic removal and ionic pair effects on transaction sodium amounts in soil and sodium absorb rate in alkali and salty soils. In this evaluation, totally 188 different rated samples according to solution salts with ability to translate to agricultural soils collected as mix and tested by standard methods. In order to correct errors in transaction sodium amounts measurement resulted by anionic removal via Bower & Hatcher method and soil solution ionic pair effects calculation has taken place with geochemical software named MINTEQ. To evaluating SAR in this study, it is supposed both practical SAR not corrected ion pairs named (SARP) and real SAR named (SAR a) which is for pair-ionic complexes are the same and their parameters relation in solution ionic mixture affected in abovementioned area as follows: SAR a= 0.1524+1.1506× SARP R2=0.991

A slippery slope for soil carbon in sub-boreal B.C.? ARTHUR L. FREDEEN1,2, CLAUDETTE H. BOIS2, DARREN T. JANZEN2, PAUL T. SANBORN1,2 1

Natural Resources and Environmental Studies Institute, UNBC; Ecosystem Science and Management Program, UNBC, Prince George, B.C. V2N 4Z9 [email protected]

2

Keywords: forest carbon stocks, forest management, soil carbon, topography The influence of slope position (i.e. ecological drainage class: mesic, subhygric and hygric) on soil, litter, debris, and biomass carbon (C) stocks were examined in a hybrid spruce (Picea glauca (Moench) Voss x Picea engelmanii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) dominated forest in the ~ 9,250 ha Aleza Lake Research Forest (ALRF) in central British Columbia. From 2003-2005, 147 plots were measured in mesic, subhygric and hygric stands, respectively, with stand ages ranging from 5 to 350+ years. Mineral soil C stocks measured in all plots to 47 cm depth, and in a subset of plots to 107 cm depth were significantly influenced by ecological stand type where hygric> subhygric> mesic (107, 95, and 84 t ha-1), respectively. Stand age had no significant effect on either mineral soil or forest floor litter C stocks indicating their resilience to partial-cut and clearcut forest harvesting systems historically implemented throughout the study area. Woody debris, herbs, shrubs, small trees and large trees were all significantly influenced by stand age. Large trees were the only ecosystem component that showed a strong positive linear relationship with stand age while the remaining components displayed nonlinear changes. Soil C, as a proportion of ecosystem C, was proportionately higher in hygric versus drier sites and in younger versus older stands. In the final analysis, subhygric stands had the highest total ecosystem C stocks in the ALRF, having approximately 18% more C than mesic and hygric stands, principally due to higher mineral soil C stocks (than mesic stands) and higher large tree carbon stocks (over hygric stands).

Beyond ‘k’: Vegetation and disturbance drivers of boreal forest soil carbon JAMES W. FYLES Department of Natural Resource Sciences, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, QC H9X 3V9 [email protected] Keywords: forested peatlands, Sphagnum, aspen, fire, forest management Getting ‘k’, the decomposition rate constant(s) right is a crucial aspect of modelling soil carbon. Estimating the values for carbon inputs is another. But these modelling parameters are, themselves, under the influence of less proximate ‘drivers’, which may be linked to each other or to different drivers. This presentation explores soil carbon in the context of a system that involves several drivers, as well as feedback loops that can lead to stability or push the system in one direction or another. The research deals with a complex of soils that occur in the boreal black spruce forest south of James Bay in northwestern Quebec. The undulating terrain, developed following deglaciation and the draining of glacial Lake Ojibway, is dominated by clay-rich tills with occasional coarser glacial-fluvial deposits. The current land surface is a complex of peatlands and forested uplands. Upland soils range from brunisolic to gleysolic and organic but the dominant functional feature of all soils is the thick organic layer on the surface, which is derived mainly from moss and stores as much as 200 Mg C/ha. Carbon dynamics and storage in these soils is intimately linked to the genesis of the surface organic horizons which is controlled by interactions among vegetation composition, plant residue quality, decomposition rate, and the chemical quality, water retention capacity and ignitibility during fire of the remaining organic matter. Sphagnum organic residues are inherently slow to decompose. As in peatlands, the presence of Sphagnum is associated with organic accumulation. Ericaceous shrubs may also retard decomposition. Aspen litter decomposes more rapidly and may exclude Sphagnum due to its physical presence, in contrast to black spruce needles which pass through the photosynthetic moss layers. As decomposition progresses, water holding capacity of organic layers increases and hydraulic conductivity drops, resulting in conditions that promote Sphagnum and reduce the potential for loss of organic horizons during a fire. Ignitability during fire depends on ash and moisture contents meaning that deeper, more decomposed layers are less likely to burn. ‘H’ horizons in these soils may represent long-term residual layers accumulated over many fire rotations. Fire, and to some extent logging, remove surface organic layers result in compact fibric organic horizons with a black surface that can reach very high temperatures on sunny days and limits revegetation. Exposed, highly decomposed ‘H’ layers appear to promote the establishment of Polytrichum moss, which itself provides conditions facilitating entrance of other plant species including feathermoss and aspen.

Ultimately, it may be possible to model the dynamics of carbon in these ‘peaty’ forest soils by finding a ‘k’ value that integrates the complexity of processes involved. However, linking such a model to changing disturbance or climate may require more explicit representation of these processes and their interactions.

Estimation du stock de carbone dans les sols de la Tunisie TAHAR GALLALI1, NADHEM BRAHIM1 1

Unité de Recherche Pédologie 04/UR/10-02. Faculté des Sciences de Tunis, Département de Géologie Campus Universitaire, Tunis 2092, Tunisie. [email protected]

Mots clés:, Carbone organique, stock, séquestration, sol, Tunisie En Tunisie, les différents types de sols peuvent être groupés en sept grandes unités de sols. A partir de l’estimation du stock de carbone organique dans chacune des sept grandes unités pédologiques, nous avons estimé le stock total du pays. Les calculs pour tous les sols sont pour les deux tranches 0-30cm et 0-100cm. Les résultats montrent que d’une manière générale le stock de carbone diminue en allant du Nord vers le Sud de la Tunisie, cette différence de stockage est liée au climat et au couvert végétal qui semblent les deux facteurs majeurs agissant sur la séquestration du carbone. L’unité des sols la plus riche est celle des sols bruns au nord du pays sous forêts et sous climat subhumides : 217t/ha, alors que la plus pauvre est celle de l’unité des lithosols au sud du pays sous végétation maigre et sous climat désertique : 25t/ha. La répartition verticale du stock de carbone organique dans les différents sols montre une décroissance avec la profondeur. De ce fait, les couches superficielles sont les plus riches en les comparant avec les autres les plus profondes et jusqu’à un mètre de profondeur. Le stock de la tranche 0-30cm par rapport à celle de un mètre de sol varie de 24% à plus que 40%, respectivement pour les sols les plus pauvres aux sols les plus riches. Par sommation des stocks des différentes unités de sols, on a obtenu le stock total dans les sols de la Tunisie. Sur la profondeur des trente premiers centimètres, le stock est évalué à 0.961Gtc, alors qu’il est de 1.353Gtc pour un mètre de profondeur.

Importance des matières organiques dans la stabilisation des sols sableux de la Tunisie et leur résistance à l’érosion TAHAR GALLALI & ABDELHAKIM BOUAJILA Unité de Recherche Pédologie. Faculté des Sciences de Tunis. El Manar 2092 Tunis. Tunisie [email protected] Mots clés : matière organique, substances humiques, stabilité structurale, érosion, Tunisie Une très grande partie de la surface de la Tunisie, caractérisée par des sols à texture grossière, supporte une activité agricole intense. Dans ces Terres l’importance de régénérer la réserve organique est fondamentale pour améliorer les propriétés physiques des sols et augmenter leur résistance à l’érosion éolienne et hydrique. Cette étude vise à (i) étudier le rôle des différentes fractions organiques dans la formation et la stabilité des agrégats de ces sols (ii) discuter les conséquences de cette relation sur la résistance à l’érosion hydrique et éolienne. Sept différents horizons de surface A ou Ap, échantillonnés dans les régions du Nord et du Centre de la Tunisie, constituent le support de ce travail. L’analyse de la matière organique a concerné le carbone organique total (COT), le carbone organique particulaire (COP), les polysaccharides (PEEC) et les composés humiques (AH+AF). Deux techniques de la mesure de la stabilité des agrégats sont utilisées, la stabilité structurale à sec et la stabilité structurale à l’eau. Les résultats sont présentés sous forme de DMP (stabilité à sec) ou MWD (stabilité à l’eau). L’analyse des différentes fractions organiques prouve que les sols agricoles ne disposent que d’une faible quantité des matières organiques totale, labile (POC + PEEC) et humifiée (AF+AH). Les résultas montrent aussi que la stabilité structurale à sec est importante pour tous les horizons (2.71 mm
Nitrogen cycling in a maize cropping system receiving mineral fertilizer and different quality residues ROBERTA GENTILE*1, BERNARD VANLAUWE2, JOHAN SIX1 1

Department of Plant Sciences, University of California, One Shields Ave., Davis, CA, 95616 USA; TSBF-CIAT, P.O. Box 30677, Nairobi, Kenya [email protected]

2

Keywords: residue quality, N fertilizers, immobilization, mineralization, plant N uptake Concerns about sustainability of agroecosystems management options in developed and developing countries are more than ever pertinent. The Integrated Soil Fertility Management paradigm, which is strongly advocated in Sub-Saharan Africa, recognizes the possible interactive benefits of combining organic residues with mineral fertilizer inputs on agroecosystem functioning. Primary mechanisms for these benefits include (i) the temporary immobilization of mineral N due to the addition of an organic residue thereby improving the synchrony of N supply by the soil and by the plant, or (ii) the improved soil condition, such as increased water holding capacity, by adding an organic residue in addition to mineral fertilizer thereby improving plant growth and resource use efficiency. However, these beneficial interactions may be controlled by residue quality. The objectives of this study were to determine the effect of different quality N inputs on N cycling under field conditions. We hypothesized that combining low quality residue with mineral N would reduce potential system losses of N by synchronizing N release with plant uptake. The experiment was conducted at Embu, Kenya on a research trial initiated in 2002 to examine the long-term effects of application of different quality organic residues and mineral N fertilizer. The experiment had a split plot design with the organic residue input as the main plot and fertilizer application as the subplot. For the present study, we sampled from residue treatments consisting of a control plot with no residue, high quality Tithonia diversifolia residue (3% N), and low quality maize (Zea mays) stover residue (0.7% N) with residues applied at a rate of 1.2 Mg C ha-1. Subplots received either 0 or 120 kg N ha-1 as calcium ammonium nitrate in a split-application, and maize was grown each season. During April to September 2007 we monitored soil mineral N and plant growth during the 11th growing season of the trial. Soil was sampled to 150 cm in 30-cm increments 5 times during the season. Plant biomass samples were also collected at time of soil sampling and measured for dry weight as well as N content. Extractable mineral N in the soil profile varied with residue and fertilizer inputs throughout the growing season. The T. diversifolia treatments had an average of 20 kg N ha-1 more extractable mineral N than the control and maize treatments up to 29 d after planting, indicating early season N release from the high quality residue. The application of mineral N fertilizer at 30 and 49 d after planting increased extractable mineral N in all 120 kg N ha-1 treatments. However, the maize+120 kg N ha-1 treatment maintained lower extractable mineral N than the control and T. diversifolia treatments implying an immobilization of the fertilizer N. Corresponding with higher levels of extractable mineral N during the growing season, the treatments with mineral N fertilizer additions produced more plant biomass and had higher plant N uptake than treatments without mineral fertilizer. The early season release of N under high quality T. diversifolia residues did not translate into greater end of season biomass production and may indicate higher N losses from the agroecosystem. Conversely, the application of low quality maize +120 kg N ha-1 showed lower levels of available N throughout the season yet produced an equivalent amount of biomass to the other residue input treatments. This provides support for our hypothesis that combining low quality residue with mineral fertilizer leads to more efficient N cycling.

Modeled evapotranspiration for spring wheat from the 2nd generation prairie agrometeorological model MARK GERVAIS*, PAUL BULLOCK, RICK RADDATZ Department of Soil Science, University of Manitoba, Winnipeg, Manitoba [email protected] Keywords: evapotranspiration, spring wheat, prairie agrometeorological model The 2nd Generation Prairie Agrometeorological Model (PAM2nd) for spring wheat simulates root-zone soil moisture, crop development, and the atmosphere’s capacity to take-up water vapour in order to derive an estimate of evapotranspiration (ET) for agricultural regions. Two unique aspects of PAM2nd are: (1) it models the vertical profile of the planetary boundary layer (PBL) to simulate the atmospheric capacity for water vapour, and (2) it was designed to use minimal surface meteorological inputs (daily maximum and minimum temperature, daily precipitation) in order to maximize the number of weather stations that could be utilized. Due to the scarcity of meteorological stations on the Canadian Prairies, and their limited instrumentation, this latter feature was essential to obtain estimates of ET at enough locations to be representative of the variation across the Prairies. The first objective of this study was to validate the root-zone soil moisture and crop components of PAM2nd at a variety of locations reflecting the variation in soil and climate in western Canada in order to improve the estimation of evapotranspiration from spring wheat on the Canadian Prairies. Model calibration was conducted using detailed soil water measurements collected from spring wheat test plots at Melfort, Swift Current, Regina, Winnipeg and Carman during the 2003 to 2006 growing seasons. This investigation led to modifications to PAM2nd that improved the RMSE of soil moisture modeling (reported elsewhere) and provided improved confidence in the ET estimates of the model. The second objective was to compare the estimates of evapotranspiration from the modified PAM2nd model to estimates from a simplified water balance and from the FAO56 Penman-Monteith method (Allen et al., 1998). This presentation deals with the second objective. Run-off and deep percolation were not measured at the study sites. As a result, comparisons of ET estimates were limited to periods that did not experience intense precipitation, nor have a high water table. Actual rates of ET from the FAO56 Penman-Monteith method were obtained using a crop and water-stress coefficient. Estimates of ET from PAM2nd, FAO56 and water balance for each time period will be compared and the results will be presented. Reference List

Allen, R.G., Pereira, L.S., Raes, D., Smith, M. 1998. Crop evapotranspiration: Guidelines for computing crop water requirements. Irrigation and Drainage Paper 56, Food and Agriculture Organization of the United Nations, Rome, Italy.

Prairie Agrometeorological Model (PAM2nd): modeled soil moisture from spring wheat MARK GERVAIS*, PAUL BULLOCK, RICK RADDATZ Department of Soil Science, University of Manitoba, Winnipeg, Manitoba [email protected] Keywords: soil water, evapotranspiration, spring wheat, prairie agrometeorological model The 2nd Generation Prairie Agrometeorological Model (PAM2nd) for spring wheat simulates soil moisture, crop development, and the atmospheric demand for water vapour in order to derive daily and seasonal estimates of evapotranspiration from agricultural regions. The latter significantly affects crop yield and quality, while the former affects the occurrance and severity of thunderstorms, and associate summer severe weather including drought. More accurate modeled estimates of evapotranspiration will improve our ability to predict these important impacts. The objective of this study was to validate the root-zone soil moisture of PAM2nd for spring wheat using detailed soil water measurements collected from test plots at Melfort, Swift Current, Regina, Winnipeg and Carman during the 2003 to 2006 growing seasons. The comparison of the daily values of measured and modeled root-zone soil moisture from the original version of PAM2nd over all site-years gave a RMSE of 62 mm (12% of field capacity). PAM2nd consistently overestimated root-zone soil moisture during the second half of the growing season for many of the site-years. It was determined that modeled canopy resistance generally increased too rapidly with the depletion of soil moisture. The canopy resistance function was modified so that canopy resistance would not start to increase until the soil moisture content was below 50% of the available water holding capacity. This modification improved the overall RMSE to 56 mm (11%). The greatest impacts were at Swift Current in 2004 and at Melfort in 2003. The improvements were by 23 mm (6%) and 24 mm (4%), respectively. In addition, modeled root-zone soil moisture was underestimated during consecutive days of precipitation. This underestimation resulted from the termination of infiltration when the top-zone reached saturation. With the removal of this restriction, the RMSE over all site-years dropped to 53 mm (10%). The RMSE for the root-zone soil moisture at Carman in 2005, and at Regina in 2004 was improved by 22 mm (4%) and 15 mm (3%), respectively. Both modifications to the model resulted in more accurate simulation of root-zone soil moisture content for spring wheat during the growing season with an overall RMSE reduction of 9 mm (2%) over all site-years from the original version of the model. The improved RMSE for root-zone soil moisture increases confidence in the modeled evapotranspiration rates produced by PAM2nd.

Data processing for XANES at the carbon K-edge in whole soil samples ADAM W. GILLESPIE*1, FRAN L. WALLEY1, RICHARD E. FARRELL1, ROBERT I.R. BLYTH2 1

Department of Soil Science, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK Canadian Light Source Inc., 101 Perimeter Rd., Saskatoon, SK [email protected]

2

Keywords: synchrotron, organic matter, carbon, X-ray absorption, XANES Soil organic carbon is a reservoir for 3-5 Pg of global C (Stevenson, F.J., 1994). The chemical nature of organic C in soil has been studied using nuclear magnetic resonance (NMR), pyrolysis massspectrometric techniques, FT-IR, and X-ray photoelectron spectroscopy. Recently, synchrotron-based X-ray absorption near edge structure spectroscopy (XANES) has been applied to the study of organic C. Data collection at the C K-edge requires the removal of spectral features introduced through carbon contamination of beamline optics by collecting normalization spectra of clean substrate at the time of sample analysis. We present a method to calibrate and normalize XANES spectra collected from whole soil samples at the C K-edge. Reference List Stevenson, F.J. 1994. Humus chemistry: genesis, composition, reactions, 2nd ed. John Wiley & Sons, Toronto, ON.

Overview of reference compounds for N K-edge XANES analysis of environmental samples ADAM W. GILLESPIE*1, PETER LEINWEBER2, FRAN WALLEY1, RICHARD FARRELL1, JENS KRUSE2, KAI-UWE ECKHARDT2, TOM REGIER3, ROB BLYTH3 1

Department of Soil Science, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK Institute for Land Use, Rostock University, Justus-v-Liebig-Weg 6, 18051, Rostock, Germany 3 Canadian Light Source Inc., 101 Perimeter Rd., Saskatoon, SK [email protected] 2

Keywords: synchrotron, unknown nitrogen, reference compounds, X-ray absorption, XANES Organic nitrogen in soil is a significant component of the global nitrogen cycle, encompassing agricultural, environmental and economic issues through fertilizer use. The unknown chemical forms of nitrogen in soil represent 30-50% of the total organic nitrogen pool. The contribution of these unknown forms of N to the global N2O budget can not currently be determined. Techniques such as pyrolysis-field ionization mass spectrometry (Py-FIMS), pyrolysis-GC/MS, and 15N NMR have been used to characterize soil organic nitrogen (SON). Techniques based on pyrolysis, however, have been criticized as being fundamentally flawed by workers who argue that the N heterocycles identified using these techniques are nothing more than artefacts of the pyrolysis. Conversely, 15N NMR techniques have been questioned by workers who contend that the low natural abundance of 15N and the inherent insensitivity of the 15N nucleus in NMR studies has allowed heterocylic N to go undetected using NMR. Synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy has been proposed as a potential corroborating technique that can be applied toward the detection of organic N (including heterocyclic N) compounds in unfractionated soil. This presentation covers a library of spectra for reference compounds recorded for use in the detection of N-containing compounds in unknown spectra in soil organic matter, and discusses some advantages and disadvantages of this technique.

Soft-ray spectroscopic exploration of acid-treated boreal forest soil ADAM W. GILLESPIE*1, ANDREW HANSON2, COLIN MINIELLY2, PALAK SURYAVANSHI2, SAFAL SURYAVANSHI2, MARYAM WASEEM2, JACQUELINE GREGOIRE2, TRACY WALKER3, ROBERT BLYTH3 1

Department of Soil Science, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK Centennial Collegiate Academy of Science and Technology, 160 Nelson Rd., Saskatoon, SK 3 Canadian Light Source Inc., 101 Perimeter Rd., Saskatoon, SK 2

[email protected] Keywords: synchrotron, soft X-ray absorption, nitric acid, boreal forest

This experiment was an exploration of possible effects of acid rain on Quebec boreal forest soil. Our interest was piqued by the susceptibility of this soil to acid rain due to low buffering capacity and its geographic potential for exposure to acid rain. As a result of emissions legislation, sulfuric acid is becoming less of an issue, so we studied the effects of nitric acid. We used Soft X-Ray Absorption Spectroscopy in the range 295 – 2000 eV to investigate the soil using the SGM beam line at Canadian Light Source. Survey scans were used to identify the principle constituents in the soil and narrow our focus. Detailed scans were taken of mineral and organic components including nitrogen, iron and aluminum. While many elements remained largely unaltered, our initial observations indicated a significant loss of aluminum in the acid-treated soil. The results suggested that acid treatment selectively removed species of aluminum from the soil. In our experiment we explored the implications for the effects of nitric acid rain on Quebec soils.

Assemblages of ericoid mycorrhizal and root-associated fungi from Vaccinium membranaceum across an elevation gradient in BC’s eastern Rocky Mountains MONIKA GORZELAK*1, HUGUES B MASSICOTTE1, SARAH HAMBLETON2 1

College of Science and Management University of Northern BC 3333 University Way Prince George, BC, Canada V2M 4Z9 [email protected]

2

Biodiversity (Mycology and Botany) Agriculture and Agri-Food Canada K.W. Neatby Building, Central Experimental Farm 960 Carling Avenue Ottawa, Ontario K1A 0C6

Root-associated fungi may form mutualistic ericoid mycorrhizas with ericaceous plants. Given different habitats and abiotic factors, the community of fungi associated with a particular root system is hypothesized to change in response to changing needs of both fungus and plant. Fungi associated with Vaccinium membranaceum (huckleberry) roots were assessed over four elevations on McBride peak in British Columbia’s eastern Rocky Mountains. Ten randomly selected plants were excavated from each targeted zone: the alpine (highest elevation), Engelmann-Spruce sub-alpine fir and Interior Cedar Hemlock (mid-elevation), and Sub-boreal spruce (lowest elevation). Plants at higher elevations were older and had higher leaf mass to area ratios than those at lower elevations. Higher elevation sites were wetter and had more acidic soils with lower soil nitrogen content compared to lower elevation sites. Fungal diversity was assessed directly (extraction of fungal DNA from roots) and indirectly (culturing from surface sterilized roots). A total of 460 fungal cultures were isolated, yielding 20 different fungal taxa. On average, each plant had five distinct fragments, each one representing a different taxon, using Length-Heterogeneity PCR, and three cultured taxa; maximum yields were 20 fragments and five taxa. For the same plant, there was no correlation between the values obtained by the two approaches. Analysis indicated that alpine plants associated with significantly different assemblages of fungi compared to lower elevations, for both direct and indirect approaches. Phialocephala fortinii was most commonly isolated, occurring frequently at lower elevations sites. Cryptosporiopsis sp. were also found at lower elevations, but in lower abundance. Rhizoscyphus ericae and Meliniomyces were found most often at higher elevations. Although ecological function is not well understood in situ, V. membranaceum fungal assemblages vary over an elevation gradient.

Responses in belowground community structure and function to variable retention harvesting SUSAN J. GRAYSTON1, J.A. ADDISON2, N. BASILIKO1+, S.M. BERCH3, N. BERG1, S.P. DARADICK1~, K. DEL BEL1, D.M. DURALL4, L.E. DEMONTIGNY3, M.D. JONES4, T.S. PANESAR2, C.E. PRESCOTT1, D.S. SRIVASTAVA5 1

Belowground Ecosystem Group, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4 [email protected] 2 Royal Roads University, Victoria, B.C. 3 B.C. Ministry of Forests, Victoria, B.C. 4 UBC-Okanagan, Kelowna, B.C. 5 Department of Zoology, University of British Columbia, Vancouver, B.C. + Now Dept Geography, University of Toronto at Mississauga ~ Now Koppert Canada, ON Keywords: Forests, soil microorganisms, soil fauna, variable retention harvesting Variable retention of living trees is increasingly being favored as an alternative to clear-cutting in forest management. Soil organisms have a vital role in nutrient cycling, so preservation of a functioning soil community is essential for ecosystem function. Currently, only retention of woody debris and limitation of soil scalping are recommended to protect soil organisms after harvest. However, a more suitable management treatment may be preservation of living trees on harvested sites, providing soil organisms with continually replenishing sources of energy from tree roots and litter. The aim of this project is to assess the potential of green tree retention (GTR) as a management tool to maintain soil functioning and site productivity after harvesting. This project brings together multidisciplinary researchers, applying a range of novel techniques to quantify changes in soil microbial and faunal diversity and function in response to harvesting. The project is using STEMS installation near Elk Bay on Vancouver Island, Canada. This experiment has allowed us to examine the same soils pre- and post-harvest. We determined how soil communities change, whether key species are lost, and if GTR of different aggregate sizes (5 - 40 m diameter) cast different size ‘shadows’ of influence. Preharvest 95% of the soil fauna and a distinct microbial community were found in the forest floor (FF), indicating GTR could serve as refugia for colonization of disturbed areas following harvest. Postharvest most soil macrofauna and collembola were influenced more by FF disturbance, than by living trees. However, mites and pauropods declined from patch centres out into the cut area. Mycorrhizal diversity and microbial activity decreased 10-15 m from the edge of all but the smallest patch. The results suggest patches will need to be >1 tree and within 20 m of each other to ameliorate change in soil organisms and their functions.

Hydrostatics of frozen soil PIETER H. GROENEVELT Department of Land Resource Science University of Guelph, Guelph, Ontario, N1G 2W1 [email protected] Keywords: frozen soil, ice ratio, ice pressure In contrast to rigid, non-frozen soils, a frozen soil does not have a unique water retention curve (WRC). Like for swelling soils, the WRC is dependent on the load (overburden) pressure. In contrast to non-frozen swelling soils, the WRC of a frozen soil is also dependent on the temperature. A theory is presented, formulating the dependence of the WRC on load pressure and temperature. This formulation requires the definition of the envelope-pressure potentials and the frost potentials of both, the liquid water and the ice in the soil. These potentials are expressed in terms of the void ratio, the ice ratio, the moisture ratio, the ice ratio equivalent and the moisture ratio equivalent. The relations between the variable are intrinsic properties of the porous medium. The theory presents the measurement of volume ratios as an alternative to the measurement of the equilibrium liquid and ice pressures, both being extremely difficult. Some data found in the literature are recalculated and presented in relevant form. Reference List Groenevelt, P.H. and Kay, B.D. 1977. Water and ice potentials in frozen soils. Water Resources Res. 13: 445-449 Groenevelt, P.H. and Kay, B.D. 1980. Pressure distribution and effective stress in frozen soil. Pages 597-610 in Ground Freezing, Norwegian Institute of Technology, Trondheim, Norway.

The tortuous path of water molecules in soil and the hydraulic conductivity PIETER H. GROENEVELT Department of Land Resource Science, University of Guelph, Guelph, Ontario. N1G 2W1 [email protected] Keywords: hydraulic conductivity, tortuosity Water molecules in soil are hardly ever “themselves”. They are constantly under some form of “stress”. They are pulled in different directions by gravitational, osmotic, adsorptive, London-Van der Waals, etc. forces. The hydraulic forces drive the water molecules from high to low hydraulic potential. The macroscopic result is a flux of water that is related to the hydraulic gradient via the hydraulic conductivity. Since the early 50’s great progress has been made to estimate the hydraulic conductivity function from hydrostatic data. Based on the Poiseuille and the capillary rise equations, the hydraulic conductivity function can be described by what is known as the Burdine model. A recent model for the water retention curve allows the Burdine model to be expressed directly in terms of incomplete gamma functions. These incomplete gamma functions are now readily available on PC’s using software such as Mathcad. The remaining unsolved mysteries are of a microscopic, geometric nature. They may be called “tortuosity” and/or “connectivity”. “Patterns of behaviour” will be presented showing the precise macroscopic (cumulative) effects of these microscopic intricacies.

Reference List Groenevelt, P.H. and Grant, C.D. 2001. Re-evaluation of the structural properties of some British swelling soils. European J. of Soil Sci. 52: 469-477. Groenevelt, P.H. and Grant, C.D. 2004. A new model for the soil-water retention curve that solves the problem of residual water contents. European J. of Soil Sci. 55: 479-485. Grant, C.D., Groenevelt, P.H. and Robinson, N.I. 2008. Application of a recent soil water retention model to predict the hydraulic conductivity. European J. of Soil Sci. (submitted).

Ecological consequences of rapid urban development in Edmonton, Alberta BAOJING GU*1, 2, YING GE1, SCOTT X. CHANG2, CHANGHUI PENG3, JIE CHANG1 1

College of Life Sciences, Zhejiang University, Hangzhou 310058, P. R. China Department of Renewable Resources, 442 Earth Sciences Building, University of Alberta, Edmonton, Alberta, T6G 2E3 3 Institut des sciences de l’environnement, Département des sciences biologiques, Université du Quebec à Montréal, Case postale 8888, Succursale Centre-Ville, Montréal, QC, Canada, H3C 3P8 [email protected] 2

Keywords: urbanization, air pollution, migration, oil and gas industry, household Because of the development of the oil and gas and other related industries in Alberta that started in the 1960s, Edmonton as the capital and the second largest city has experienced rapid urban development. Here, we study the impact of the development of the oil and gas industry on urbanization, migration, air and water quality, microclimate, and household resource consumption from 1960s to present. A model about the impacts on environment from population, affluence, household, technology and governmental policies was built up to predict the environmental development in this research. Results showed migration had contributed over 80% of the population changed in Edmonton in the past four decades, driven by the industrial development. Industrial development also directly caused air and water quality to deteriorate from the 1970s to the middle of the 1980s, after which technological advancement helped to improve air quality. In addition, housing starts doubled while the average household size (number of people in a household) decreased in this period, causing more resource consumption per capita. Also the urbanization has negative effects on the biodiversity and nutrient biogeochemistry linking to the environmental pollution. Projecting to 2025, we suggest that increases in population and affluence will likely expand human impact on the environment. Managing the tradeoffs between socioeconomic development and environmental protection will be a major challenge for governments at various levels. Reference List Blair, R. B. 1999. Birds and butterflies along an urban gradient: surrogate taxa for assessing biodiversity? Ecol Appl 9: 164-70. Chertow M. 2001. The IPAT equation and its variants: changing views of technology and environmental impact. J Ind Ecol. 4: 13-29. Dale, V., Archer, S., Chang, M., and Ojima, D. S. 2005. Ecological impacts and mitigation strategies for rural land management. Ecol Appl. 15: 1879-1892. Dietz, T., Rosa, E. A., and York, R. 2007. Driving the human ecological footprint. Front Ecol Environ. 5(1): 13-18. Kalnay, E., and Cai, M. 2003. Impact of urbanization and land-use change on climate. Nature. 423: 528-31. Liu, J., Daily, G. C., Ehrlich, P. R., and Luck, G. W. 2003. Effects of household dynamics on resource consumption and biodiversity. Nature. 421: 530-33. Stern DI. 2004. The rise and fall of the environmental Kuznets curve. World Dev. 32: 1419-39. Wackernagel, M., Schultz, N. B., Deumling, D., Linares, A. C., Jenkins, M., Kapos, V., Monfreda, C., Loh, J., Myers, N., Norgaard, R., and Randers, J. 2002. Tracking the ecological overshoot of the human economy. P Natl Acad Sci USA. 99: 9266-71. York R, Rosa E, and Dietz T. 2002. Bridging environmental science with environmental policy: plasticity of population, affluence and technology. Soc Sci Quart. 83: 18-34. Zhao, S., Da, L., Tang, Z., Fang, H., Song, K., and Fang, J. 2006. Ecological consequences of rapid urban expansion: Shanghai, China. Front Ecol Environ. 4:341-6.

Is phosphorus dosage in balance with soil P carrying capacity and phosphorus removal by vegetable crops in Quebec organic soils? JULIE GUÉRIN*1, LÉON-ÉTIENNE PARENT1 1

Department of Soils and Agri-Food Engineering, Université Laval, Québec, Qc, Canada G1K 7P4 [email protected] Keywords: phosphorus, organic soils, saturation, fertilisation, Mehlich III Many vegetable crops are grown on 10 000 ha of organic soils in south western Quebec, Canada according to fertilizer guidelines from Quebec (CRAAQ, 2003), Michigan (Lucas, 1982) and Florida (Sanchez, 1990). Although many fertilization trials showed no responses to phosphorus (P) fertilizers, many watercourses draining these areas in North America have high P levels. The aim of this study was to determine the suitable P dose for each crop based on a soil P saturation index and on agroenvironmental thresholds found for Quebec cultivated organic soils. Between 2002 and 2005, we conducted 66 field trials to determine crop response to added P and P removal by the crops. Six soil fertility classes (0.03-0.05; 0.05-0.08; 0.08-0.11; 0.11-0.14; 0.14-0.17; > 0.17) were determined. Response probability within soil fertility classes was computed with a power test. Preliminary results will be presented during the poster presentation. Reference List CRAAQ. 2003. Reference guide for crop fertilization. 1st Ed., Centre de Référence en Agriculture et Agroalimentaire du Québec, Québec, Canada, 297 pp. Guérin, J., L.E. Parent, and R. Abdelhafid. 2007. Agri-environmental thresholds using mehlich III soil phosphorus saturation index for vegetables in histosols. Journal of Environmental Quality. 36:975982. Lucas, R. 1982. Organic soils (Histosols). Formation, distribution, physical and chemical properties and management for crop production. Res. Rep. 435, Agric. Exp. Sta. and Coop. Ext. Serv., Michigan State Univ., East Lansing, and Agric. Exp. Sta., Inst. Food Agric. Sci., Univ. Florida, Gainesville, FL, 79 pp. Sanchez, C.A. 1990. Soil-testing and fertilization recommendations for crop production on organic soils in Florida. Techn. Bull. 876, Agric. Exp. Sta., Inst. Food Agric. Sci., Univ. Florida, Gainesville, FL, 44 pp.

Basal and potential denitrification of soils under monoculture and rotational cropping of corn, soybean and winter wheat with/without red clover XIAOBIN GUO*1,2, CRAIG F. DRURY 1, XUEMING YANG 1, RENDUO ZHANG 2 1

Greenhouse and Processing Crops Research Centre, Agriculture & Agri-Food Canada, Harrow, Ontario, Canada N0R 1G0 2 School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P.R. China [email protected] Keywords: basal denitrification, potential denitrification, monoculture soil, rotational soil Denitrification is controlled by a number of environmental variables and soil factors including the cropping history. The objective of this study was to compare the basal and potential denitrification rate of soils collected from both monoculture cropping of corn, soybean, winter wheat with/without underseeded red clover and from 2 and 3-yr crop rotations (corn-soybean, and corn-soybean-winter wheat with/without underseeded red clover). Each phase of the rotation was present each year and hence 12 treatments were examined. Using the acetylene inhibition technique, the basal denitrification rate with/without added nitrate (75 mg N kg-1 dry soil) and potential denitrification rate with a soluble C source (glucose at 300 mg C kg-1 dry soil) and NO-3-N (50 mg N kg-1 dry soil respectively) were measured at 20°C over a 5 hr period. Basal denitrification rates (no N added) ranged from 0.53 to 3.84 mg N2O-N kg-1 d-1, the lowest rate in monoculture winter wheat with red clover and the highest rate in soybean phase of the 3yr rotation (C-S-WW). Denitrification with added N ranged from 0.50 to 3.84 mg N2O-N kg-1 d-1, the lowest rate in monoculture soybean and the highest rate in winter wheat with red clover phase of the 3-yr rotation (C-S-WW+RC). Potential denitrification rates ranged from 6.24 to 11.04 mg N2O-N kg-1 d-1, the lowest rate in monoculture corn and the highest rate in the corn phase of the 2-yr rotation (C-S). No significant relationship was found between basal denitrification rate and soil nitrate concentration. However, there was a significant correlation between basal denitrification rate and soil anaerobic respiration rate (CO2) (R2=0.74, P<0.01). After incubation, the soil nitrate concentrations increased by 11-197% in these three incubations while the soil ammonium concentrations remained constant. Hence denitrification was controlled by carbon source in these soils as the current crop, the previous crop and added C affected N losses.

Selenium in Soils and Crops and its Significance in Human Health UMESH C. GUPTA Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, 440 University Avenue, Charlottetown, PE C1A 4N6 [email protected] Keywords: selenium fertilization, soybeans, heart disease, cancer Selenium (Se) is an anti-oxidant and an essential trace mineral for livestock and humans. It is an integral component of a powerful anti-oxidant enzyme, glutathione peroxidase (GSXph) and acts as a strong reducing agent. Soils of Prince Edward Island and most of eastern Canada are very low in Se; consequently the feed and food crops produced contain insufficient quantities of Se to prevent Se deficiency. So far Se has not been proven to be essential for plants. Consequently, interest in Se for plants is related to the quality of crops as animal feed or as human food. The soil-plant system is the main source of Se for animal feed and human food. A number of world regions are deficient in Se to meet the needs of animals and humans. Areas receiving sulfur fertilization contain low Se because sulfur competes with Se uptake by plants. The first case of Se deficiency disease in humans was reported in the Keshan district in the northeastern part of China (Chen et al. 1980). The disorder known as cardiomyopathy was found in adolescents and children. This disorder results in weak hearts with poorly developed cardiac muscle. Specific immune, reproductive, neurological, and cardiac disorders are found in humans deficient in Se, as reviewed by Gupta and Gupta (2002). Additionally, certain cancers and chronic diseases appear to be related to Se in the human diet. A higher Se status in humans has proven beneficial in specific disease states such as pediatric cardiomyopathy. Selenium fertilization of soil, Se application as a foliar spray or seed treatment with Se at 10 g ha-1 applied as selenate results in crops sufficiently enriched with Se to protect against Se deficiency. Soybeans have been found to be more effective in absorbing Se than other grains, e.g., barley (Gupta and MacLeod, 1994). Some good sources of Se include legumes, Brassica, Brazilian nuts, dry fruits, chicken, oysters, clams, high-Se yeast and Se-fortified salts. Reference List Chen, X., Yang, G., Chen, J., Chen, X., Wen, Z. and Ge, K. 1980. Studies on the relations of selenium and Keshan Disease. Biol. Trace Elem. Res. 2: 91-107. Gupta, U.C. and Gupta, S.C. 2002. Quality of animal and human life as affected by selenium management of soils and crops. Commun. Soil Sci. Plant Anal. 33: 2537-2555. Gupta, U.C. and MacLeod, J.A. 1994. Effect of various sources of selenium fertilization on the selenium concentration of feed crops. Can. J. Soil Sci. 74: 285-290.

Reclaiming phosphogypsum stacks in central Alberta INGRID HALLIN*1, M. ANNE NAETH1, DAVID S. CHANASYK1, CONNIE K. NICHOL2 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta Agrium, Fort Saskatchewan, Alberta [email protected]

2

Keywords: phosphogypsum, reclamation hydrology Phosphogypsum (PG) is an acidic byproduct of the phosphate fertilizer industry. As PG is created it gets mixed with water and transferred to a settling pond where it eventually settles out of solution. Once the settling pond reaches a predetermined capacity it is drained, leaving behind a stack of dry PG. Currently there are no regulations regarding closure and reclamation procedures for PG stacks in Alberta; each site is dealt with on an individual basis. One common objective for each site is to prevent water from percolating through the drained stack, as water collecting within PG can lead to dissolution of gypsum and surface instabilities such as sinkholes. Agrium Incorporated operations in Fort Saskatchewan, Alberta, produced phosphate fertilizer from 1965 until 1991. During this time approximately 5 million tonnes of PG were stored between 4 stacks. Upon decommissioning in 1991, topsoil was spread directly onto the PG of the outer slopes of each stack before seeding a prairie grass mix. Research is currently underway to characterize the conditions of these stacks to determine if further reclamation efforts are required. One of the main research objectives is to quantify infiltration and runoff on the stacks to evaluate the effectiveness of the soil and vegetation alone as a protective cover for PG. Preliminary results suggest that water infiltration is greater than runoff at most sites on the stacks, and data from TDR probes will be used to describe small scale moisture profiles. Moisture profiles will be compared with topsoil depths to identify potential relationships between depth of water percolation and depth of soil cover. These relationships could be useful for establishing common reclamation practices for other PG stacks in similar climate conditions.

Site sensitivity to biomass and nutrient removals at British Columbia’s long-term soil productivity study sites KIRSTEN HANNAM1, SHANNON BERCH1, BILL CHAPMAN2, MIKE CURRAN3, STÉPHANE DUBÉ4, GRAEME HOPE5, RICHARD KABZEMS6, MARTY KRANABETTER7, PAUL SANBORN8 1

BC Ministry of Forests and Range, Victoria, BC BC Ministry of Forests and Range, Williams Lake, BC 3 BC Ministry of Forests and Range, Nelson, BC 4 BC Ministry of Forests and Range, Prince George, BC 5 BC Ministry of Forests and Range, Kamloops, BC 6 BC Ministry of Forests and Range, Dawson Creek, BC 7 BC Ministry of Forests and Range, Smithers, BC 8 University of Northern British Columbia, Prince George, BC [email protected] 2

Keywords: long-term soil productivity, biomass harvesting, forest floor, whole-tree harvesting, stemonly harvesting

Long-term soil productivity (LTSP) experimental sites have been established in several economically important forest types across British Columbia as part of an international effort to examine the long-term consequences of soil compaction and organic matter removal for soil productivity. The study design of each installation includes stem-only and whole-tree harvesting treatments, as well as whole-tree harvesting + forest floor removal. Together, the forest floor and surface organic debris serve numerous ecological functions, providing habitat for forest biota, regulating soil microclimate and serving as a seed bank, nutrient reserve and source of cation exchange sites. Given the growing interest in forest biomass as an alternative energy source, the viability of biomass harvesting is a matter of critical concern and the LTSP sites are ideally positioned to address some of these issues. Preliminary analyses of the biomass and nutrient data from the oldest LTSP installations, established in the early ‘90s in the Sub-boreal Spruce biogeoclimatic zone, indicate that whole-tree harvesting can increase potential nutrient removals over stem-only harvesting by at least 50%, although the forest floor remains a more critical reserve of many nutrients, e.g., sulphur. Furthermore, the amount of base cation reserves in slash and tree boles can be comparable to the pools of exchangeable base cations in the forest floor and mineral soil. This paper will summarise and compare the amounts of nutrients and biomass displaced by three levels of organic matter removal in the 14 LTSP sites located across the province and will contrast these with the pools remaining in the soil profile. Although the LTSP installations are located on mesic sites with zonal soils and, as such, extremes in site conditions have been avoided, stands in which relatively more of the available nutrients and base cations are contained in the aboveground biomass may be more sensitive to organic matter displacement. In addition, recent work on these and other sites suggests that pre- and post-harvest tree species composition and parent material mineralogy have a strong influence on stand regeneration following biomass removal. It is critical to understand the implications of organic matter removal for soil productivity in order to develop guidelines that preserve the many ecological functions of surface organic materials and ensure that biomass harvesting is conducted only under appropriate conditions.

Effect of wheat dried distillers’ grains on the composition of feces and manure from feedlot cattle XIYING HAO, MONICA BENKE, GREG TRAVIS, DARRYL GIBB, TIM MCALLISTER, ASHLEY STRONKS AAFC Lethbridge Research Centre, 5403 1st Ave S. Lethbridge, Alberta Canada [email protected] Keywords: nitrogen, phosphorus, VFA, soluble ions, feedlot manure With the expansion of the ethanol industry, wheat-based dried distillers’ grains with solubles (DDGS) could become a significant component of diets for feedlot cattle. Substitution of DDGS for grain in feedlot rations could alter nutrient levels in manure in such a manner that changes in manure management may be necessary to avoid adverse impacts on the environment. This study was conducted to investigate the impact of including DDGS in finishing rations for feedlot cattle on the composition of feces and manure. In a feeding trial that encompassed backgrounding (55 d) and finishing (133 d) phases, steam-rolled barley grain in the diets was replaced with wheat DDGS in 20% increments. The backgrounding diets contained (DM basis) 55% barley silage, 5% supplement, and 40, 20 or 0% barley grain + 0 (control), 20 or 40% wheat DDGS, respectively. Finishing diets contained 10% barley silage, 5% supplement, and 85, 65, 45 or 25% barley grain + 0 (control), 20, 40, or 60% wheat DDGS. A fifth finishing diet was prepared that contained 60% wheat DDGS plus 1% additional limestone to increase the Ca:P ratio from 1.1 to 1.6:1 (denoted DDGS60Ca). The diets were fed to heifers penned individually and bedded on woodchips. Samples of feces and of manure (a mixture of feces, urine, and bedding) were collected at the end of the backgrounding phase and monthly during finishing. Samples were analyzed for total C (TC), total N (TN), total P (TP), and water-extractable NO3–, PO43–, SO42–, Cl-, NH4+, Na+, K+, Mg2+, and Ca2+ ions, as well as the volatile fatty acids (VFA) acetate, propionate, butyrate, iso-butyrate, valerate, iso-valerate and caproate. Fecal N and manure P concentrations increased (P < 0.05) with increasing levels of DDGS in diets. In addition, concentrations of water soluble NH4+ and P in feces and manure were higher (P < 0.05) with DDGS40 and DDGS60 diets than with Control. Limestone supplementation resulted in a 49% decrease in soluble P concentration in feces and manure samples (DDGS60Ca vs. DDGS60). The higher DDGS concentrations resulted in (P < 0.05) lower water soluble Ca+2 and Mg+2 content in manure, whereas K+ concentration was not affected. Increases (P < 0.05) in isobutyric, valeric and isovaleric acids in feces were also observed with increasing levels of DDGS in the diet. These VFA were strongly and positively correlated with feed N levels. Our study demonstrates that feeding DDGS to cattle will increase N, P and VFA excretion into the environment, which should be considered when developing manure management strategies.

Greenhouse gas and ammonia emissions when composting manure from cattle fed dried wheat distillers’ grains with solubles XIYING HAO, GREG TRAVIS, MONICA BENKE, FRANCIS J LARNEY, TIM A. McALLISTER, DARRYL GIBB AAFC Lethbridge Research Centre, 5403 1st Ave S. Lethbridge, Alberta Canada [email protected] Keywords: nitrogen, GHG, NH3, open windrow composting Dried distillers’ grains with solubles (DDGS) are a co-product of ethanol production. Because of the growing demand for ethanol, further increases in DDGS available for use in livestock feeds are expected. Including DDGS in diets for livestock could affect animal manure properties and impact manure management strategies. The objectives of this study were to investigate the rate of greenhouse gas (GHG) and ammonia emissions during composing and final compost properties of manure from feedlot cattle fed DDGS compared with a traditional barley-based finishing diet. The study was conducted in summer-fall 2007 at the Lethbridge Research Centre (semiarid climate) and included two treatments: manure from cattle fed a traditional barley grain/barley silage-based finishing diet (control) and manure from cattle fed a finishing diet in which 60% of the barley grain was replaced with wheat DDGS (DDGS diet). There were two replications per treatment. Manure consisted of feces, urine and woodchip bedding materials. Windrows were established in summer 2007 and turned on days 8, 14, 20, 36, 43 and 71 using a tractor-pull Earthsaver windrow turner (Fuel Harvesters Equipment Inc., Midland, TX). At establishment and at the end of composting, 12 manure samples were collected from each compost windrow and analyzed for pH, moisture content, total C (TC), total N (TN) and available N (NH4+, NO3– and NO2–). A vented chamber technique was used to measure greenhouse gas and NH3 surface fluxes during composting, weekly during the first 3 wk and every 2- to 4 wk for the remainder of the composting period. Gas samples were analyzed by gas chromatography for O2, CO2, CH4 and N2O concentrations. For NH3 emission, 100-mL bottles containing 10 mL de-ionized water were set inside and outside the chamber and exposed for 1 h. The concentration of ammonia-N (NH4+ and dissolved NH3) in de-ionized water samples was determined using an Astoria Pacific 2 autoanalyzer. The rate of NH3 emission was calculated as the ammonia-N differences between bottles inside and outside the chamber during the 1-h exposure. Cumulative emissions were approximated by assuming that the measured fluxes represented the average for each period between samplings. Total GHG emissions over the composting period were expressed per initial unit surface area. Final compost from the DDGS diet manure had a lower TC content than the control, but similar TN content, which reflected the levels initially in the manure used. In addition, as compared with the control, DDGS compost had higher moisture content, lower pH, higher NH4+ and NO3–, similar NO2-N contents and a greater fraction of its TN was in available form (NH4+ and NO3–). Composting DDGS manure led to greater O2 consumption, similar CO2 and CH4 emissions, and higher N2O and NH3 emission rates compared with the control. The higher N2O and NH3 emissions from DDGS treatment were related to the high available N content in the DDGS manure and final compost. Increased use of DDGS in livestock diets may have environmental repercussions that include greater emissions of GHG (N2O) and NH3 during manure composting. For end use, however, enhanced availability of N in the compost is beneficial for crop production.

Long-term effects of timber harvesting on soil bacterial, archaeal, and eukaryal genetic community structures along a depth-gradient MARTIN HARTMANN1, SANGWON LEE1, BILL K. CHAPMAN2, STEVEN J. HALLAM1, WILLIAM W. MOHN1 1

Department of Microbiology and Immunology, Centre for Microbial Diversity and Evolution, University of British Columbia, Vancouver BC, Canada 2 Ministry of Forests and Range, Victoria BC, Canada [email protected] Keywords: microbial community structures, long-term soil productivity, depth gradient, genetic tools Maintenance of forest soil quality is crucial to ensure high productivity as well as economic and environmental sustainability of commercial forests. The impact of timber harvesting on the soil microbiota by means of organic matter (OM) removal and soil compaction potentially affects soil quality, since microorganisms provide fundamental ecosystem services including nutrient cycling, decomposition and transformation of organic materials and toxic compounds, and pest and disease control. The long-term soil productivity (LTSP) research program in Northern America emphasizes to i) evaluating impact of timber management on long-term soil productivity and sustainability, ii) developing monitoring tools and soil quality indicators, and iii) establishing guidelines to maintain ecosystem sustainability while optimizing productivity. Approximately one decade after timber harvesting in the LTSP experimental site at Skulow Lake BC, we investigated the impact of complete above-ground OM removal and severe soil compaction on the community structure of soil bacteria, archaea and eukarya in comparison to an unmanaged forest reference site. Effects were monitored along soil gradients spanning four different soil horizons in both sites to assess the depth impact of timber harvesting and to identify changes of the most abundant species among the specific layers. Soil microbial community structures among all three domains of life were determined using ribosomal intergenic spacer analysis (RISA). Bacterial and eukaryal diversity was high at both sites and among all layers, whereas diversity of archaea was rather low especially in the top soils. Microbial community structure in the upper soil layers was significantly affected by timber harvesting when compared to the reference stand, but effects were less pronounced at greater depth. In addition, timber management altered similarities between the soil layers. In the natural site, mineral layer AE revealed highly similar community structures to the underlying layer AB, whereas in the managed site layer AE was more similar to the organic topsoil. Gradients of physicochemical parameters measured in these soils strongly correlated with the changes in microbial community structures. These results indicated that more than ten years after timber harvesting soil microbial community structures along the depth gradient were still strongly altered by OM removal and soil compaction. Indicator analysis of the genetic profiles elucidated phylotypes affected by forest management. The most abundant indicator phylotypes were phylogenetically identified by large scale cloning and sequencing analysis, using a novel approach of concatenating small subunit (SSU) rRNA genes and ribosomal intergenic spacers. These sensitive and high-throughput genetic tools might help to quantify long-term effects caused by timber management practices and to establish guidelines for the forest industry.

Lime induced iron chlorosis and early defoliage of Plane tree (Platanus orientalis L.) in Tehran YOUSEF HASHEMINEJHAD1, MOHAMMAD JAFAR MALAKOUTI 2, MARYAM MOFIDPOOR3 1

Research assistant, National Salinity Research Center, Nahalestan Ave., Azadegan Blvd, Yazd, Iran; Professor of Tarbiat Modares University, Tehran, Iran; 3 Soil Scientist, Herio Research Ltd, 21333 48ave, Langley, BC, V3A 3M6 [email protected]

2

Keywords: iron, defoliage, chlorosis, lime, plane tree Tehran city is famous for its ancient plane trees, however in the early summer trees are inundated by chlorosis and defoliage. Since soil and water resource in Tehran were carbonatic by nature, objective of this study was to test lime induced iron chlorosis hypothesis. 100 trees of the same age were selected in Laleh Park in the center of Tehran. The five treatments were control, replacement of the calcareous soil around the root with fully decomposed manure, foliar spray of iron sulfate, trunk injection of ferric ammonium citrate and soil application of Fe- EDTA. These treatments were arranged in completely randomized design with four replications. During the growing season, the green color of leaves and leaf area were measured monthly, defoliage was ranked based on visual interpretation between zero to 100 and chemical composition of leaves was analyzed before and after the treatments. In all treatments green color of leaves and Fe concentration of the leaves were significantly improved compared to control, although there was no difference between replacement treatment and other methods of Fe application, which indicated that Fe deficiency was lime induced. Leaf analysis results after defoliage showed an abrupt increase in B concentration of leaves up to toxicity level. A future study could investigate the source of B toxicity in plane trees and the possibility of early defoliage based on B toxicity.

Quantification of soil morphology by computed tomography RICHARD J. HECK1, IOANA A. TAINA1, THOMAS R. ELLIOT1 1

Department of Land Resource Science, University of Guelph, Guelph, ON, N1G 2W1 [email protected]

Keywords: micromorphology, porosity, aggregate, digital imagery, image analysis Typically, the characterization of soil morphology, at the field level, has yield qualitative and semiquantitative data (such as Day, 1982); attempts have been made to derive quantitative interpretations from such data (McKeague et al., 1986). A similar situation exists with conventional descriptions of soil micromorphology (at least 5x magnification) using thin sections (Stoops, 2006). Arguably, such data types have limited the utility of morphological information in the quantitative modeling of soil systems. With the adaptation of digital imaging and computerized image analysis, quantification of pedofeatures in thin sections became possible (Mermut and Norton, 1992). Advancements in image classification, especially context-based, offer the potential for multi-scale interpretation of digital imagery (Taina and Heck, in preparation). Despite these advancements, thin sections are tedious to prepare and present fundamental limitations – it is practically impossible to accurately deduce 3D morphology from 2D slices. X-ray computed tomography (CT) has become a popular technique for studying the spatial configuration of soil components, and it is now being used to improve our understanding of many soil physical, chemical and biological properties and processes (Taina et al, 2008). Recent advancements in CT scanner technology, have given us the ability to readily acquire X-ray imagery, at spatial resolutions of only several μm, for soil samples several cm in size. Though the discrimination among solid soil phases still present technological challenges, voids can be readily distinguished from the soil matrix, permitting their 3D quantification. With the establishment of standardized imaging and image processing protocols, CT imaging can provide an efficient means of quantifying soil morphology. Reference List Day. J.H. 1982. Manual for describing soils in the field. Revised. Canada Expert Committee on Soil Survey. LRRI Contribution No. 82-52. Research Branch, Agriculture Canada, Ottawa. 175 pp. McKeague, J.A., Wang, C. and Coen, G.M. 1986. Describing and interpreting the macrostructure of mineral soils-a preliminary report. LRRI Contribution N. 84-50. Research Branch Agriculture Canada. Ottawa. Mermut, A.R. and Norton, L.D. 1992. Digitization, processing and quantitative interpretation of image analysis in soil science and related areas. Special Issue, Geoderma 52: No.3/4. Stoops, G. 2003. Guidelines for analysis and description of soil and regolith thin sections. Soil Science Society of America, Inc., Madison, Wisconsin, USA: 184 pp.

Taina, I.A., Heck, R.J. & Elliot, T.R. 2008. Application of X-ray computed tomography to soil science: a literature review. Can. J. Soil Sci. 88: 1-19. Taina, I.A. and Heck, R.J. Object-based image analysis in the interpretation of Gleysol thin sections. In preparation.

Community capacity building for urban agriculture in the city of Vancouver, British Columbia; the role of soil and microclimate assessment MELISSA A. IVERSON*1, ART BOMKE1 1

University of British Columbia, 2357 Main Mall, Vancouver, BC V6T 1Z4 [email protected]

Keywords: urban agriculture, community gardens, assessment, soil quality, microclimate Community gardens plots are in great demand in Vancouver, but community groups interested in establishing gardens face several environmental barriers. Of these obstacles, poor soil quality, substandard microclimates, and the inability of community members to assess these important components of their future gardens create corresponding management challenges. The goal of this study is to aid community members in overcoming these obstacles through the development of an online soil quality and microclimate assessment tool that enables gardeners to adopt best-management practices. Use of the tool does not require previous soils knowledge. Information about soil processes and issues pertaining to urban soil and microclimate quality emerge through the assessment. The soil quality and microclimate assessment tool is applied to three case study community gardens and runs as a practice exercise during soils workshops given in communities in Vancouver. Each case study site assessment consists of the compilation of a site history, and an analysis of the site’s physical, chemical, and biological soil quality indicators, using community-accessible methods. To ensure accuracy, each community-accessible method is calibrated to a standard laboratory method. The results of the soil quality and microclimate assessments will provide community groups with valuable information about their soil’s nutrient availability, possible risks associated with contaminants in their soil, and microclimatic data to aid in plant selection and landscape design as these groups move through the development phase of garden establishment. Collaborative soils workshops are held with interested community groups to build an understanding of soil processes, the effects of microclimate characteristics, and to develop best management practices for use in their gardens. As a component of these workshops, participants take part in a soil quality and microclimate assessment activity, using the community-accessible methods employed in the case studies. Based on participant feedback, the assessment tool is edited to make it more accessible to the general public and ensure its practicality to community members faced with environmental obstacles to garden establishment.

Development of a reclamation cap for phosphogypsum stacks in Alberta, Canada MALLORY JACKSON*1, M ANNE NAETH1, DAVID S CHANASYK1, CONNIE K. NICHOL2 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta Agrium, Fort Saskatchewan, Alberta [email protected]

2

Keywords: phosphogypsum, reclamation Phosphogypsum (PG) is an acidic by product generated from the production of phosphorus fertilizers. It is commonly stacked in large piles around the world including Alberta, Canada. This research involves reclamation of phosphogypsum stacks to a natural area in central Alberta. Current legislation requires a 1 m topsoil cap overlying PG. With an annual precipitation of 400 to 500 mm, it was hypothesized this cap depth could be reduced. The research focused on the effect of soil cap depth on water infiltration and percolation, leaching of potential contaminants, emissions of radon gas and suitability for vegetation growth. Experimental plots with varying depths of topsoil (0, 7.62, 15.24, 30.48, 45.72 and 91.44 cm) were constructed and seeded with one of five grasses in spring 2007. The first year research results will be presented

Innovations in the delivery of Soil Science distance education courses NOORALLAH JUMA1 1

President, Salman Productions Inc., 141 Garnet Road, Sherwood Park, Alberta T8A 2S5 [email protected] Keywords: Introductory Soil Science, web-based interactive learning, e-courses, course materials In 1999, we launched pedosphere.com with a vision to revolutionize Soil Science education by creating high quality, interactive resources that engage both students and instructors, and become a repository of Soil Science information through partnerships with major international organizations. Great advances have been made in terms of computing power, bandwidth and development of broadcasting technologies over the past decade and conditions are now more favorable to deliver Soil Science distance education courses. The objective of this presentation is to examine innovations in the delivery of Soil Science educational materials. I will examine different components of a distance education course and present information on the conceptual layout of course manual/textbook, the use of a test center, development of audio lectures with PowerPoint support, and use of tutorials to promote engagement and learning. Hopefully, all these will be packaged in the our first distance education course scheduled to be launched in the Fall 2008. We are also seeking collaboration with the Soil Science community to build a variety of educational resources in order to reposition our discipline in the realm of Agriculture, Forestry, Environmental Science, Ecology and Earth System Science.

Refining designs of onsite, at-grade, soil-based sewage treatment systems NOORALLAH JUMA1, BALDEV S. CHHABRA1, ALF DURNIE2 AND ANGUS CHU3 1

Professor of Soil Microbiology & Biochemistry and Research Associate, respectively, Onsite Wastewater Treatment Research Laboratory, Department of Renewable Resources, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3 2 Chief Inspector, Private Sewage, Codes and Standards. Alberta Municipal Affairs, Box 428, Provincial Building 201 Centre Street, Drumheller, ABT0J 0Y0 3 Associate Professor, Department of Civil Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4 [email protected] Keywords: coliforms

soil-based sewage treatment, loading rates, orifice spacing, soil temperature, fecal

Pressurized, at-grade, private sewage treatments have a great potential of being used in Alberta but the designs of these systems have to address the issues of point loading, high loading rates, instantaneous saturated flow, uneven application of effluent over the length of the laterals, and movement of total and fecal coliforms and nitrate-N to a depth of 60 cm and beyond. The objective of this study was to test treatment effectiveness of four designs for dispersing treated sewage effluent in soil. A research site was established in Leduc County, Alberta in the Fall 2007. Four independent laterals were set up to test the impact of reducing the loading rate from 5.6 gal/sq.ft/day (2.74L/dm2/day) to 1.00 gal/sq.ft/day (0.49L/dm2/day) and orifice spacing from 3 ft (90cm) to 2 ft (60 cm). A 4-zone valve was used to cyclically distribute equal volumes of treated sewage effluent to the laterals. Temperature sensors were installed at the orifice and between orifices on each of the four laterals at depths of 5, 20, 50 and 100 cm. The data are being recorded on data loggers. The soil under the laterals, which protected by a chamber and mulched with wood chips, did not freeze and accepted the wastewater over the winter months. The temperature profile was directly related to the volume of effluent flowing through the orifice. Thus, higher soil temperatures were recorded under the orifices and at mid-point positions along the laterals receiving effluent at 5.6 gal/sq.ft/day at 3 ft orifice spacing compared to those receiving effluent at 1.0 gal/sq.ft/day at 2 ft orifice spacing. These data also gave an indication of the distribution pattern of wastewater in soil and showed that the at-grade systems were fully operational during the winter months. The soil will be sampled in the summer to determine gravimetric moisture content, fecal and total coliforms, and amounts of ammonium, nitrate and Kelowna P to determine the treatment effectiveness of these soil-based dispersal systems. These data will also be used to refine orifice spacings and loading rates of onsite, at-grade, soil-based sewage treatment systems.

Assessing crop response to fertilizer N: the Delta Yield Concept R. GARY KACHANOSKI Bentley Research Chair (Soil, Water and Environment), Dept.of Renewable Resources, 4-42 Earth Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada. T6G 2E3 [email protected] Keywords: soil fertility, crop response, nitrogen Understanding and accurately predicting the optimum amount of fertilizer N to apply to crops remains a challenge. Most methods for estimating N fertilizer rate are based on an expected yield (or yield potential) despite numerous studies indicating that optimum N rate is poorly predicted by yield potential. The objective of this paper is to derive macro-relationships between recommended N rate and Delta Yield, which hold across large sets (years, location) of fertilizer response curves. Delta yield is defined as the increase in grain yield over check yield, at the recommended N rate. Generalized Taylor Series (2nd , 3rd order) approximations are used to describe the crop fertilizer N response function. Consistent with inverse analysis, various assumptions about the relationship between crop nitrogen use efficiency NUE and applied fertilizer N rate are then examined to determine which constraints would result in unique macro-relationships between Delta-yield and optimum applied fertilizer N rate. The analysis indicates that for 0th and 1st order relationships between NUE and applied N rate, unique macro-relationships between Delta-yield and optimum applied fertilizer N rate should exist. The relationships are non-linear but very similar. A number of fertilizer N response studies carried out over the past 25 yrs for a range of crops (corn, barley, wheat, canola) are reviewed and compared to the derived macro-relationships. The implications and the usefulness of the Delta yield concept based on the comparison to historic crop N response studies are discussed.

Phosphorus desorption studies in biosolids-amended and inorganicallyfertilized soils GOURANGO KAR*1, JEFF J. SCHOENAU2, DEREK PEAK1 Department of Soil Science, University of Saskatchewan, 51 Campus Drive Saskatoon, SK, CA, S7N5A8 [email protected] Key words: Desorption, XANES spectroscopy This study was conducted to compare the speciation and behavior of P in soils receiving either different biosolids or inorganic fertilizer, as assessed by phosphate desorption, and synchrotron X-ray absorption near edge structure (XANES) spectroscopy. The objectives of this study were to: i) compare P desorption kinetics in biosolids applied soils to inorganic fertilizer amended soil; (ii) investigate the effects of soil to solution ratios and pH on P desorption from soils amended with inorganic fertilizer and biosolids; and, (iii) perform solid state speciation of soil samples before and after desorption with P XANES spectroscopy to determine how P desorption affects speciation. Soil samples were analyzed that received maximum rate biosolids (67.2 Mg ha-1 yr-1) and inorganic fertilizer (336 kg N, 224 kg P, and 112 kg K ha-1 yr-1) application for 32 years. Soil samples were collected from four replications of inorganic fertilizer and maximum rate biosolids amended soils. Two composite soil samples were prepared by mixing four replications of each treatment from the surface layer (0-15 cm) of the soil for desorption experiments. The amount of desorbed P decreased as the soil:solution ratio increased from 0.005 to 100 g L-1 for both soils and the desorption was typically higher in inorganic fertilizer applied soil than in biosolids applied soil. The effect of pH on P desorption was pronounced, and desorption was higher at pH 5 than pH 7.5 for both soils. A continuous flow desorption method was also used to measure cumulative P desorption over time. Cumulative P desorption in inorganic fertilizer applied soil (894.5 mg P kg-1) was higher than in the biosolids amended soils (572.9 mg P kg-1) over 20 hr period time. First-order and parabolic diffusion kinetic equations were used to model the desorption data from the continuous flow technique. This revealed that the P desorption rate was faster (and chemically-controlled) at initial stages and slower (and diffusion-limited) at later stages. The desorption rate was much faster in inorganic fertilizer applied soil than in biosolids applied soil. Phosphorus K-edge XANES results showed that there was excellent repeatability in spectra of replicates, and that the residual post-desorption for the inorganically-fertilized soil was crystalline calcium phosphates, whereas in the biosolids the spectra resembled poorly-crystalline calcium phosphates and other poorly ordered sorption products.

Impact of wildfire intensity and clear-cutting on nitrogen-cycling bacterial communities in British Columbia forest soils NABLA KENNEDY1, KEITH N. EGGER1 1

Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC V2N 4Z9 [email protected]

Keywords: wildfire, logging, Douglas-fir, denitrifiers, nosZ In 2003, wildfires in British Columbia burned 13 times more forest than in the average year, mostly in the southern interior. Much of the forest burned was dominated by the commercially valuable conifer species Douglas-fir, which requires ectomycorrhizal colonization to successfully regenerate. Nitrogen is typically the most limiting nutrient in temperate coniferous forests, and the nitrogen cycle is strongly affected by fire. We studied the effects of fire severity in nitrogen-cycling genes in the mycorrhizosphere of Douglas-fir seedlings as they regenerated after the fire. Root windows were set up vertically in the soil, with a removable front panel used to access the seedling rhizosphere soil surface. Windows were established in control, lightly burned, and severely burned plots, as well as two types of logged plots (clearcut and screefed). Soil scrapings from the root window-soil interface were taken and the community structure of nitrogen-cycling genes was resolved using terminal restriction fragment length polymorphism (T-RFLP) analysis. The denitrifying community was targeted by analysing the nitrous oxide reductase (nosZ) gene. Both fire and logging were found to impact the soil denitrifying community. All types of disturbance (light burn, severe burn, clearcut, and screefing) significantly increased the richness of denitrifiers relative to the control plots. All treatments had significantly different community structures, suggesting that they affected the denitrifying community in different ways. Analysis of the most abundant and frequent genotypes revealed that most had highest abundances in one particular treatment, suggesting each disturbance selected for a particular community of denitrifying species.

Investigation on steep slope soil stability with geogrid in the arid and semi arid area (Varamin-Iran) KAVEH KHAKSAR High Education Center of Jahad Keshavarzi, Soil And Water Department, 5 Km of Mahshar Road, Hemat Av. Karaj-Iran [email protected]. Keywords: erosion control, geogrid, slope soil stability, arid and semi arid area

Steep slope soil stabilization can be done using geogrid. In steep slopes, regeneration of vegetation is very difficult. The usage of geogrid in slope over 85% can be successfully technically and economically. To determine polymer net works, plots of 12×2 meters were constructed. They were enclosed with steep plates; runoff and sediments gathered and were led to gathering plots. Different treatments were considered for the research. These treatments were: Geogrid with natural grassland covering, Geogrid with seeding aboriginal grassland species, without geogrid and with natural grassland covering and without geogrid with seeding aboriginal grassland species in the two slopes (85% & 110%). Data from nine events were measured and analyzed in SPSS software. We concluded that there is significant difference in plots conducted in 110% but there is no significant difference in slope 85%. Different treatments along with replications were chosen. Totally plots where in geogrid were used, soil degradation shows lower rate. Conclusions and analysis proved that it is very economic compared to other treatments. So geogrid can be used with great success in arid and semiarid areas (Khaksar, 2007). Reference List Bhatia, S.K., Smith, J.L., Lake, D. and Walowsky, D. (2002). “A Technical and Economic Evaluation of Geosynthetic Rolled Erosion Control Products in Highway Drainage Channels,” Geosynthetics International, Vol. 9, No. 2, pp. 125-148. Coluzzi, E. et al., 2005. Stabilizazione superficiale del Ciglio della Rupe di orvieto Mediante Geocelle. Tenax SpA.-Viegano (Lc) Italia. P.4. Herold, A. 2003. One of Europe's tallest green faced geosynthtic reinforced retaining structures, Geokunststoff GbR Herold & Khler, Weimar, Germany. Khaksar, K. 2006. Study of geogrid applicability for erosion control, X, Congress of Croatian Society of Soil Science, Sibenik, 14-17, lipanj 2006. Khaksar, K. 2007. Economic evaluation of geogrid application for steep slope stability, 5th international congress of the European Society for Soil Conservation, Palermo, Italy, June, 25-302007. Rimoldi, P. et al., 2000. La difesa dall’ erosione mediante Geocelle e sui canali del serbatoio di bilancio (Firenze). Tenax SPA.

The effects of forest fertilization on C sequestration and greenhouse gas emissions in plantation forests of British Columbia AMER KHAN1*, NATHAN BASILIKO2, VENETA YOLOVA1, SUSAN J. GRAYSTON1, CINDY E. PRESCOTT1, RÉAL ROY3, BRAD SEELY1, BILL MOHN1, GORDON WEETMAN1 1

Belowground Ecosystem Group, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4 2 Department of Geography , University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, Canada, L5L 1C6 3 Department of Biology, Faculty of Science, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada, V8P 5C2 [email protected] Keywords: forests, greenhouse gases, C sequestration, fertilization Canada contains 401 million hectares of forest and woodland with 64 million hectares in BC. Canada’s ratification of the Kyoto Protocol in 2002 has generated interest in the role of forest management as a potential tool to reduce net greenhouse gas emissions. Forest fertilization is used by industries to increase timber yield and shorten rotation times, however the potential of fertilization to also increase soil C sequestration has not been characterized in detail. In addition, potential negative fertilization effects on soil emissions of N2O, CO2 and consumption of CH4 are largely unknown. We characterized C storage in trees and soil and measured annual CH4, N2O and CO2 fluxes, soil nutrients and microbial communities in 3, 25 yo conifer plantations (lodgepole pine, Douglas-fir, western hemlock) under simulated operational fertilization with urea (200Kg N) or fertilizer mix (N, P, micronutrients) and unfertilized control. Short-term fertilization plots were used to examine immediate effects on GHG and underlying chemical and microbial controls. N fertilization increased the individual tree biomass and increased soil C sequestration in the lodgepole pine and western hemlock stands due to a higher percentage of soil C (under lodgepole pine) and higher humus accumulation (under hemlock). In the short-term plots, for up to 7 months following fertilization we measured soil fluxes of CO2, CH4, and N2O and soil N, P, and microbial biomass dynamics. Fertilization resulted in an initial increase in CO2 efflux as urea was mineralized, but rates returned to control levels within 14 days. Beyond rapid mineralization of urea to NH4+, there was surprisingly little transformation of N over the measurement period. NH4+ was largely retained in the soil organic horizons with moderate uptake by microbial biomass and little oxidation to nitrate. In the lodgepole pine site, fertilization with urea led to a short-lived suppression of soil CH4 uptake, presumably due to NH4 inhibition of CH4 monoxygenases. N2O efflux was significantly greater than 0 in fertilized plots at only 1 measurement date in 1 forest type (Douglas-fir) following fertilization. We conclude that in western Canadian conifer plantations with acidic soils, initial impacts of fertilization on soil greenhouse gas dynamics are short-lived and relatively minor.

Movement of water, nutrients, fecal coliforms and somatic coliphages in soil columns receiving wastewater through point and drip application systems SAJJAD S. KHANDKER*1, SHANJIDA KHAN1, NOORALLAH JUMA1 1

M.Sc. student, Research Assistant and Professor of Soil Microbiology & Biochemistry, respectively, Onsite Wastewater Treatment Research Laboratory, Department of Renewable Resources, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3 [email protected] Keywords: coliforms

soil-based sewage treatment, point application, groundwater contamination, fecal

Pressurized, at-grade, private sewage treatment systems have a great potential of being used in Alberta but the designs of these systems have to address the issues of loading rates and point application of effluents through perforated pipes. The objective of the study was to assess movement of water, nutrients, fecal coliforms and somatic coliphages in soil columns receiving wastewater through point and drip application systems. Eight columns (20 cm id, 100 cm height) were packed with sieved soil from three horizons of an Orthic Gray Luvisol to simulate field conditions.. Wastewater was applied at a rate of 0.5L/minute and 1.66 mL/minute for point and drip application system, respectively. The dose volume for both the systems was 0.5L/day. After applying the effluents for 60 and 90 days, the columns were sacrificed and a total of 36 samples were collected from each column that corresponded to a central core, inner and outer tori (d=6.7 cm) and 6 depths (1-10, 10-20, 20-35, 35-55, 55-75 and 75-100 cm) in duplicate. The model for statistical analysis a complex split plot design with two treatments (point and drip application), 2 replications, 2 durations, 3 lateral layers and 6 depths. The water content during the experimental periods was below the saturation point and followed the similar pattern in both application systems. There were no significant differences in NH4-N and NO3-N content between treatments and two durations but the amounts decreased with depth and from the central core to the outer torus. There were significant differences in Kelowna PO4 content between treatments and two durations and the amounts decreased laterally and vertically. The number of fecal coliforms also decreased with depth were detected at 55 and 75 cm depths after 60 and 90 days, respectively. The distribution of somatic coliphages showed a curvilinear trend with depth. Fecal coliforms in soil leachates were not detected during the experimental period but somatic coliphages were detected after two weeks of wastewater application. Trace amounts of NH4-N and Kelowna PO4, and higher amounts of NO3-N were detected in the leachates. During 90 days, the soil attenuated NH4N, Kelowna PO4 and fecal coliforms but nitrate and somatic coliphages moved through the soil column. The presence of coliphages and nitrate in leachates and the detection of fecal coliforms at 75 cm depth after 90 days show that these materials pose a risk of contamination of groundwater and water bodies in both application systems.

PSelf-Davis as unifying index to assess P risk across Canadian soils LOTFI KHIARI1, ERIC VAN BOCHOVE2, ANTOINE KARAM1 1

Équipe de Recherche en Sols Agricoles et Miniers, Department of Soils and Agrifood Engineering Laval University, Quebec, Canada; 2 . Agriculture and Agri-Food Canada [email protected] Key words: water soluble P, P saturation index, routine soil test P The environmental risk of P fertilization can be assessed from soil test P (STP), P sorption capacity (PSC) and P saturation index (PSI). Soil tests are already widely conducted, inexpensive, and well correlated to soluble and bioavailable P. Hence, PSI is the most common approach to identify soils with elevated P concentrations that can impact water quality. In Canada, a large variety of routine soil tests are used to characterize plant available P. Mehlich-III analysis (MIII) is often used in acidic to neutral soil of Quebec and the Maritimes. Olsen extractions are used mainly in Ontario and Manitoba. The Kelowna P-test is used in the western provinces where soil variability can be large (Saskatchewan, Alberta, British Columbia). However, P transport processes amenable to surface and subsurface P losses must also be evaluated. Water soluble P (Self-Davis or Sissingh methods) relates the different STP or PSI critical values to a general P desorption model integrating the status of P fertility with P sorption capacity of each soil. All soils of Canada can then be compared on the same or uniform basis. We propose a critical value of 4 mg PSelf-Davis /kg of soil as upper environmental limit across Canadian soils to assess the potential P risk of contaminating water.

Effect of solid cattle manure injection on nutrient recovery in a Black Chernozemic Saskatchewan soil TOM KING*1 JEFF J. SCHOENAU1 AND H. LANDRY2 1

Department of Soil Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK S7N 5A8 Prairie Agriculture Machinery, Humboldt, SK [email protected]

2

Keywords: solid cattle manure injection, nitrogen uptake, phosphorus uptake, oats Introduction: Traditional methods of applying beef cattle manure have been to broadcast (pasture land) and broadcast and incorporate (cultivated fields) the solid manure on fields. In the case of annually cropped fields, there is usually a delay in incorporating the manure such as when the manure is applied in the fall or early spring. This can result in losses from water erosion and nutrient losses due to volatilization of ammonia in the manure. If the solid manure could be placed directly into the soil (injected), this could mitigate nutrient loss and adverse agronomic and environmental effects. The objectives of this study were to examine the effect of subsurface injection of solid cattle manure (SCM) on oat crop yield and crop uptake of nitrogen (N) and phosphorus (P), using a prototype solid manure injector apparatus. Experimental Design: The experiment was conducted on a loam textured Black Chernozem soil (Cudworth association) located in east-central Saskatchewan. Solid cattle manure was applied using 4 application strategies: broadcast only, broadcast and incorporation, subsurface injection and subsurface injection + urea, at 3 rates: 9 (low), 18 (medium) and 27 (high) t ha-1. Results and Discussion: Broadcasting of solid cattle manure at the high rate produced the highest overall crop yield.. The high application rate of the broadcast treatment may have produced higher yields than other treatments as a result of a surface mat of organic residue that helped to preserve moisture and reduce evaporation under conditions of the summer drought of 2007. Oat yields on the injected SCM treatments were about 1000 kg ha-1 higher than control plots and were not significantly different from the broadcast only and broadcast and incorporated yields. Injection of SCM at the low rate achieved oat crop yields of 5500 kg ha-1, similar to other application strategies and rates. Combination of injected cattle manure plus urea produced the highest yields at the low rate of application. Grain and straw N concentrations were also highest in the injection + urea treatments. Grain P uptake was highest for injected cattle manure and broadcast and incorporated treatments at the high rate. Subsurface injection + urea at the high rate produced the highest soil extractable NO3-N (17.0 kg ha-1) in the 0-15 cm depth. Injection and injection + urea treatments produced the highest after harvest soil extractable P levels at 114 and 85 kg ha-1, respectively in the 0-15 cm depth, suggesting that injection may enhance P availability from solid manure sources. Conclusion: Response of the oat crop yield to the injection of solid cattle manure was similar to broadcast only and broadcast and incorporated applications of cattle manure. Grain and straw N levels increased when urea was added to injected manure. Injected SCM resulted in higher soil extractable NO3-N than broadcast application at the high rate of application. Injection of solid cattle manure at high rates significantly increased soil extractable P compared to other methods of application. These results suggest better N and P retention from the solid manure injection. The trials will be continued at the site for another two years. Future research will focus on a more detailed examination of N and P forms as affected by placement technology.

Plant nutrient uptake from different stone substrates: a combination of weathering and cation exchange? NINA KOELE*1, ERNST E. HILDEBRAND1 1

Institute of Soil Science and Forest Nutrition – Albert Ludwigs-Universität Freiburg, Bertoldstrasse 17, D-79098 Freiburg-Germany [email protected] Keywords: biogeochemical cycles, cation exchange, stones, tree nutrition, weathering state Standard soil fertility analyses usually reject coarse soil fraction > 2mm, because this fraction is considered of little influence on short term nutrient release. But when healthy forest growth on nutrient depleted soils, as measured in fine earth, were observed, the short term nutrient availability in coarse soil was investigated and found to be significant. Mechanisms proposed to explain how the coarse soil nutrients are taken up by trees, are mineral weathering by microorganisms (e.g. Boyle and Voigt 1973) and cation exchange processes (Koele and Hildebrand 2008). This study investigates the effect of Norway spruce seedling roots and associated ectomycorrhiza on nutrient uptake from different stone substrates. In microcosms seedlings and their ectomycorrhiza were grown on either weathered or unweathered gneiss fragments (2-6 mm). Elaborating on results from a previous microcosm experiment, the hypotheses were that 1: mycorrhizal seedlings will enhance nutrient uptake from stone protected fine earth as compared to non mycorrhizal seedlings, and 2: when no stone protected fine earth is available (unweathered substrate), mineral weathering by ectomycorrhiza will provide seedlings with nutrients. Seedlings were grown on a substrate of gneiss fragments (2-6 mm diameter, weathered or unweathered) and inert quartz. A deficient nutrient solution was added so that the substrate was the only source for Mg and Ca. Four treatments were assigned: weathered gneiss with and without spruce seedlings, and unweathered gneiss with and without seedlings. Nutrient budgets were calculated to determine nutrient fluxes from gneiss and the nutrient solution into leachate and seedlings. First results showed that seedlings survived well on both substrates, increasing significantly in biomass. The unweathered gneiss started with high cation fluxes in the leachate but after 6 weeks these declined rapidly. Weathered gneiss showed a more stable ion flux into the leachate. Mg and Ca in leachate of weathered gneiss were lower for treatment with seedlings. The different fluxes imply that cation exchange is the most important nutrient source in coarse soil. The unweathered gneiss can only provide exchangeable cations directly after sample preparation where large blocks were crushed to the desired diameter. The weathered gneiss, sieved directly from the soil in the appropiate size, can provide a constant nutrient release from fine earth infillings in weathering cracks. Thus nutrient uptake from weathered gneiss by seedlings is dominated by cation exchange. Seedlings on unweathered gneiss may use additional weathering since the low amount of exchangeable cations in leachate cannot explain healthy seedling growth. Reference List Boyle, J.R. and Voigt, G.K. 1973. Biological weathering of silicate minerals, implications for tree nutrition and soil genesis. Plant Soil 38: 191-201. Koele, N. and Hildebrand, E.E. 2008. The ecological significance of the coarse soil fraction for spruce seedling nutrition. Plant Soil in press.

SoilWeb: an interactive, on-line teaching tool MAJA KRZIC1, KELLEEN WISEMAN1, LESLEY DAMPIER1, and DAVID GAUMONT-GUAY1 1

Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4 [email protected]

Keywords: teaching of soil science, introduction to soil science Introductory soil science courses are challenging because students are required to make connections among a large number of concepts, while relying on the fundamental principles of physics, chemistry, and biology. At the University of British Columbia (UBC) the SOIL 200 - Introduction to Soil Science course is no exception. The material of SOIL 200 is extremely diverse, incorporating the aforementioned science disciplines and applying them to management applications in agriculture, forestry, and environmental protection. The SoilWeb teaching tool (http://www.landfood.ubc.ca/soil200/) was developed in 2003/04 to (1) enhance connectivity of material covered, (2) allow for inclusion of a greater variability of learning styles, (3) increase student’s motivation for learning about soil science, and (4) link the material presented in this undergraduate course to research carried out by various faculty members at UBC and scientist from various research institutions throughout Canada and North America. SoilWeb is used to support the lecture based and WebCT teaching methods, providing students with a graphical, interactive, and text web-based information online. It was developed using Macromedia Flash animation, slide shows, online quizzes and glossary, photos, and graphs combined with text and weblinks to present course material. To date, this tool has been used during four academic years and the student response has been excellent. In addition to SOIL 200, SoilWeb is also used as a review tool in several upper level courses (e.g., AGRO 401, 402, 403) offered at UBC. An interactive overview of the SoilWeb will be given during the presentation.

Calibration of CS 616 water content reflectometer for field use PRIYANTHA B. KULASEKERA*, PETER VON BERTOLDI, GARY W. PARKIN Department of Land Resource Science, University of Guelph, Guelph, ON, N1G 2W1, Canada [email protected] Keywords: WCR, TDR, calibration, water-content, CS616 Estimating soil water contents in the field is very important in studies involving soil- wateratmosphere-plant relationships. The indirect measurement technique offered by Time Domain Reflectometry (TDR) is expensive, and difficult to operate in remote locations with no electricity where it is necessary to obtain repeated measurements of water content over a longer duration. The Campbell Scientific CS616 Water Content Reflectometer (WCR) provides a better alternative for TDR for use in remote experimental sites, but requires the use of field specific calibrations instead of the manufacturers calibration equations. A CS616 Water Content Reflectometer was calibrated using field and laboratory data obtained for a loam soil. The relationship between the volumetric water content and the output period has a strong quadratic relationship which enable the estimation of water contents below 0.1 m3m-3, while the square root of relative permeability is linearly related to the volumetric water content values above 0.1 m3m-3.

Differences in temporal behaviour of soil water content in the shallow zone under tilled and no-till management systems PRIYANTHA B. KULASEKERA*, PETER VON BERTOLDI, GARY W. PARKIN Department of Land Resource Science, University of Guelph, Guelph, ON, N1G 2W1, Canada [email protected] Keywords: preferential flow, time series analysis, tilled, no-till, shallow zone

The knowledge of temporal behaviour of the soil water content in vadose zone usually assists the practitioners in planning their agricultural management practices such as application of fertilizers and irrigation scheduling. The application of agrochemicals during high levels of water movement within the soil profile could be disastrous in the presence of preferential flow since it may contribute to the rapid pollution of groundwater. The temporal changes in the shallow zone of the soil profile may reflect the existence of such processes. Therefore it is important to identify the nature of the soil water content changes over time and compare them across different tillage management practices. Soil water contents in the shallow zone (0-40 cm depth) of the soil profile were measured hourly over two consecutive growing seasons along transects located on two adjoining plots with different soil management practices, no-till and till, by placing soil water sensors horizontally in a rectangular grid. The daily average water contents were calculated for each vertical array of soil water sensors and the resulting time series was analysed for autocorrelation and power spectral density. The time series analysis indicated that the daily average water content along the vertical columns along transects represent nonstationary time series whereas the autocorrelation functions of the differenced data converged rapidly. The difference in the spectral density diagrams of the transformed data reflects the characteristic differences of the tilled and no-till plots where evidence of preferential flow is seen in no-till plot.

Forms of P in manures and their impact on P runoff losses from manure amended soils DARSHANI KUMARAGAMAGE1, DON FLATEN1, WOLE AKINREMI1, DUPE IGE1 CLAY SAWKA1, MULIKAT BAMMEKE1 1

Department of Soil Science, University of Manitoba, Winnipeg, MB, R3T 2N2 [email protected]

Key words: P runoff, manure P fractions, manure amended soils Buildup of soil phosphorus (P) with the continuous application of manure increases the risk of P runoff loss from agricultural land, leading to environmental problems such as eutrophication of surface waters. The risk of leaching and runoff losses of P is more related to the form of P than the total P present in manure (Sharpley and Moyer, 2000). For fresh manure, this risk is highly correlated with the water soluble P concentration in the manure (Kleinman et al. 2007). However, there is little information about the forms of manure and manure P that are correlated with risk of P loss after manure interacts with soil, especially for Prairie soils. In this study we quantified and compared P losses from liquid swine- and solid cattle- manure treated soils after incubating for 6 weeks, in relation to forms of P in manure. Amount of P in different fractions of manure samples were quantified using the modified Hedley fractionation. Phosphorus losses in ten treatments (4 sources of solid cattle manure, 4 sources of liquid swine manure, mono ammonium phosphate (MAP) and control) were compared in two soils (clay loam and sand) with two replicates for each treatment. Manure or fertilizer was applied to soil at the rate of 100 kg of P/ha, thoroughly mixed, incubated at 20 C for 6 weeks and packed into soil boxes. Boxes were placed at a 5% slope underneath a rainfall simulator operated according to practices used by Wright et al. (2006) providing rainfall at 75 mm h-1intensity. Runoff and percolate samples were collected over a total of 60 minutes, then analyzed within 24 h for dissolved reactive P. On a wet basis, the total P content among the sources of manure varied widely, ranging from 0.72 to 2.00 kg P/1000 L in liquid swine manure and 1.36 to 3.41 kg P/ ton in solid cattle manure. However, on a dry basis, water, NaHCO3, NaOH and HCl extractable P concentrations were higher in liquid swine manure than in solid cattle manure. After six weeks of incubation, the P concentration in runoff and total P loss were higher from liquid swine manure treated soils than from solid cattle manure treated soils. Dissolved reactive P in runoff samples and total P loss showed significant positive relationships with the amounts of inorganic P extracted with water, NaHCO3, NaOH and HCl in manure. The dominant P fraction controlling P loss due to runoff in manureamended soils after 6 weeks of incubation varied between the two soils; however, correlations between manure P fraction and P loss were generally greater for NaHCO3 extractable P than for water extractable P. The results suggest that the water extractable P content in manure is not the most reliable indicator of risk of P loss from manured soils after those manures have been interacted with soil. Reference List Kleinman, P., Sullivan, D., Wolf, A., Brandt, R., Dou, Z., Elliott, H., Kovar, J., Leytem, A., Maguire, R., Moore, P., Saporito, L., Sharpley, A., Shober, A., Sims, T., Toth, J., Toor, G., Zhang, H., Zhang, T. 2007. Selection of a water extractable phosphorus test for manures and biosolids as an indicator of runoff loss potential. J. Environ. Qual. 36: 1357-1367. Sharpley, A. and Moyer, B. 2000. Phosphorus forms in manure and compost and their release during simulated rainfall. J. Environ. Qual. 29: 1462 – 1469 Wright C.R., Amrani, M., Akbar, M.A., Heaney, D.J., and Vanderwel, D.S. 2006. Determining phosphorus release rates to runoff from selected Alberta soils using laboratory rainfall simulation. J. Environ. Qual. 35:806–814.

Prospects of reconstructing historical precipitation pH from tree ring chemistry of Pinus densiflora in Korea JIN-HYEOB KWAK1, SANG-SUN LIM1, KYE-HAN LEE2, HAN-YONG KIM3, SCOTT X. CHANG4, WOO-JUNG CHOI*1 1

Department of Biosystems & Agricultural Engineering, Institute of Agricultural Science & Technology, Chonnam National University, Gwangju 500-757, Korea 2 Department of Forestry, Chonnam National University, Gwangju 500-757, Korea 3 Department of Plant Science, Chonnam National University, Gwangju 500-757, Korea 4 Department of Renewable Resources, 442 Earth Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E3 [email protected] Keywords: Ca concentration; δ15N; δ13C; N concentration; nitrogen deposition The chemistry of annual growth rings of trees may be affected by the acidity of precipitation. We studied the relationship between N concentration, N isotope ratio (15N/14N, expressed as δ15N), C isotope ratio (13C/12C, expressed as δ13C), and Ca concentration in annual growth rings of red pine (Pinus densiflora Sieb. et Zucc.) and precipitation pH in Korea. We found that with decreasing precipitation pH (from 5.7 to 5.0) during the last 11 years of the study period when such data are available, N concentrations increased (from 0.53 to 0.99 g kg-1) while δ15N (-1.0 to -2.0‰) and Ca concentrations (0.99 to 0.80 g kg-1) decreased in the growth rings (P<0.05). These results suggested that acid precipitation increased N concentrations but decreased δ15N and Ca concentrations in the newer tree rings, as acid deposition contains N compounds with low δ15N values (Poulson et al. 1995; Choi et al. 2005) and is known to decrease the availability of Ca in the soil (Sakata et al. 2001; Padilla and Anderson 2002). A regression model, pH = 5.6 – (2.48×[N]) + Exp(0.47× δ15N) + Exp(0.27×[Ca]) (R2=0.73), was developed with the available data to relate tree ring chemistry to precipitation pH and this relationship was used to reconstruct the historical pH in precipitation for the period where there was no precipitation pH data available. Further studies using a variety of tree species in areas with long-term precipitation pH records for model validation will improve the applicability of the model for other areas and species, as the applicability of such regression models is likely site- and speciesspecific. Reference List Choi, W.J., Lee, S.M., Chang, S.X., Ro, H.M., 2005. Variations of δ13C and δ15N in pinus densiflora tree-rings and their relationship to environmental changes in eastern Korea. Water Air Soil Poll. 164: 173-187. Padilla, K.L., Anderson, K.A., 2002. Trace element concentration in tree-rings biomonitoring centuries of environmental change. Chemosphere. 49: 575-585. Poulson, S.R., Chamberlain, C.P., Friedland, A.J., 1995. Nitrogen isotope variation of tree rings as a potential indicator of environmental change. Chem. Geol. 125: 307–315. Sakata, M., Suzuki, K., Koshiji, T., 2001. Variations of wood δ13C for the past 50 years in declining Siebold’s beech (Fagus crenata) forests. Environ. Exp. Bot. 45: 33–41.

Stability analysis of spatial patterns of gas diffusion in a loamy sand JONATHAN LAFOND*1, SUZANNE E. ALLAIRE1, ATHYNA N. CAMBOURIS2, SÉBASTIEN F. LANGE1, BERNARD PELLETIER3, PIERRE DUTILLEUL3 1

Laval University, Horticultural Research Center, 2480 Hochelaga, Québec, P.Q., Canada, G1K 7P4 Agriculture and Agri-Food Canada, 979 de Bourgogne Ave, Québec, P.Q., Canada, G1W 2L4 3 McGill University, Department of Plant Science, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, P.Q., Canada, H9X 3V9 [email protected] 2

Keywords: geostatistic, diffusion, gas Diffusion is generally recognized as the main process for gas movement in soil. Two agricultural sites on loamy sands were equipped with 108 sampling points, each covering one hectare. Soil temperature, water content, and bulk density were measured at each point, two depths, and 10 times during the growing season of 2006 to calculate gas diffusion coefficients (Ds/Do) using the Millington and Quirk (1961) model. Classical statistics and multi-scale analyses with the CRAD method (Pelletier et al. 2008) served to study the spatial tendencies of Ds/Do. Variations in values of Ds/Do tend to reach 100% and showed small-scale and large-scale space distribution patterns. The stability in time (one growing season) of the Ds/Do spatial pattern will be discussed. Reference List Millington, R. J. and Quirk, J. P. 1961. Permeability of porous solids. Trans. Faraday Soc. 57: 12001207. Pelletier, B., Dutilleul, P., Larocque, G. and Fyles, J. W. 2008. Coregionalization analysis with a drift for multi-scale assessment of spatial relationships between ecological variables 1. Estimation of drift and random components. Environmental and Ecological Statistics DOI 10.1007/s10651-0080090-z.

Relationships among seral stages, plant indicators and soil indicators in the southern interior of British Columbia SARAH LAMAGNA*1, MAJA KRZIC1, REG NEWMAN2 1

Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall,Vancouver, BC V6T1Z4 2 BC Ministry of Forests and Range, 515 Columbia Street, Kamloops, BC V2C 2T2 [email protected] Keywords: seral stage, soil bulk density, rough fescue, soil polysaccharides Understanding the effects that cattle have on vegetation, soil, and hydrologic parameters is the first step in developing sensitive and unambiguous indicators of rangeland health and sustainable management practices. Cattle may affect the environment directly by trampling, grazing/browsing, and manure deposition but may also have indirect affects through interactions among altered plant species composition, hydrology, energy flows, and nutrient cycling. These effects are cumulative, in some cases the result of many decades of grazing activity. Existing plant community seral stage can be used as an integrating index of the history of grazing use. Due to its poor ability to recover from intense grazing, rough fescue (Festuca campestris Rydb.) is a good indicator of the seral stage of rough fescue dominated ecosystems. Good grazing management is essential for healthy grassland ecosystems and development of comprehensive monitoring strategies that include both vegetation and soil properties. The study objectives were to (1) determine the soil quality and plant composition of nine different sites (ranging from early to late seral stages) and (2) quantify the relationships among seral stages, soil quality indicators, and vegetation indicators. The study was carried out on rough fescue grasslands within the Interior Douglas-fir biogeoclimatic zone in the southern interior of British Columbia on sandy loam/loam Orthic Brown/Black Chernozem. The study included 20 treatment units (each with or without grazing) and the units were classified by seral stage of the ecosystem (early, mid, and late). Five 30-m long transects were randomly established per treatment unit and soil and vegetation sampling was done along these transects. Soil properties determined in May 2007 were: bulk density, aggregate stability, mechanical resistance, total C and N, polysaccharides, and pH. Plant properties measured in August 2007 were: living above-ground biomass, fallen and standing dead litter, density of rough fescue, bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A. Löve), and Idaho fescue (Festuca idahoensis Elmer), and percentage soil cover. Soil bulk density is a measure of soil compaction and as such is often determined in grazing studies. Due to substantial spatial variability of grassland soils, a large number of samples is required for appropriate bulk density determination. Our preliminary data show that the soil bulk density could be predicted from either aboveground biomass of rough fescue, litter biomass, percentage bare soil, or total C. Soil polysaccharides had a significant impact on stabilization of the smallest soil aggregates. Grouping of treatment units into early, mid, and late seral stage followed expected trends (e.g., late seral sites had higher total soil C). Findings of this study will advance range health assessments that are currently used by range managers in monitoring the effectiveness of their practices.

Spatial variability of CO2 emissions in relation to soil properties SEBASTIEN F. LANGE*1, SUZANNE E. ALLAIRE1, PIERRE DUTILLEUL2, JONATHAN LAFOND1, ATHYNA N. CAMBOURIS3, AND BERNARD PELLETIER2 1

Laval University, Horticultural Research Center, 2480 Hochelaga, Québec, P.Q., Canada, G1K 7P4; McGill University, Department of Plant Science, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, P.Q., Canada, H9X 3V9; 3 Agriculture and Agri-Food Canada, 979 de Bourgogne Ave, Québec, P.Q., Canada, G1W 2L4 2

[email protected] Keywords: geostatistics, CO2 emission, soil properties, spatial variability Agricultural greenhouse gas (GHG) emissions represent approximately 10 % of the Canadian GHG emission but their temporal and spatial variability affects the accuracy of the predicted global GHG budget. It also influences the approaches used for measuring these emissions. The main objective of this project was to measure the CO2 emissions from two agricultural fields with closed chambers over 1 ha with 108 measurement points in each field during spring 2007. Physico-chemical soil (loamy sands) properties such as density, water content, temperature, and gas (CO2 and O2) concentrations were also measured at two depths at the same points. Classical statistics and multivariate geostatistical analyses performed with the CRAD software (Pelletier et al. 2008) were used to study non-spatial and spatial tendencies in CO2 emissions and soil properties. Total variability of CO2 emissions reached 55% in one field and 76% in the second field. Variogram of the CO2 emission show spatial tendencies in both fields. Correlations with soil parameters at small and

large scales will be discussed. Reference List Pelletier, B., Dutilleul, P., Larocque, G. and Fyles, J. W. 2008. Coregionalization analysis with a drift for multi-scale assessment of spatial relationships between ecological variables 1. Estimation of drift and random components. Environmental and Ecological Statistics DOI 10.1007/s10651-0080090-z.

Manures, crop residues and fertilizers for restoring productivity to an artificially eroded soil FRANCIS J. LARNEY1, H. HENRY JANZEN1, ANDREW F. OLSON1 1

Agriculture & Agri-Food Canada, Research Centre, 5403 1st Ave. S., Lethbridge, AB T1J 4B1 [email protected]

Keywords: erosion, soil quality, soil amendments Many agricultural fields on the semi-arid Canadian prairies exhibit areas of inherently low productivity associated with loss of soil quality due to erosion. This study compared the efficacy of various amendments in restoring productivity to an artificially eroded Dark Brown Chernozem in southern Alberta. In spring 1992, fourteen amendment treatments (including various livestock manures, crop residues, combinations of straw and chemical fertilizer, and fertilizer alone) were applied to a site where the Ap horizon (.15 cm depth) had been mechanically removed to simulate erosion. The manures and crop materials were incorporated into the degraded surface on an equivalent dry weight basis of 20 Mg ha-1. The plots have been continuously seeded to spring wheat since 1992 under no-till management. Longevity of yield response to one-time application of amendments will be reported as will the efficacy of the various amendments in maintaining soil productivity and crop yield.

Who’s citing who? A look at the Canadian Journal of Soil Science FRANCIS J. LARNEY1, DENIS A. ANGERS2 1

Agriculture & Agri-Food Canada, 5403 1st Ave. S., Lethbridge, Alberta T1J 4B1 Agriculture & Agri-Food Canada, 2560 Hochelaga Blvd., Ste-Foy, Québec G1V 2J3 [email protected]

2

Keywords: Canadian Journal of Soil Science, citation database, Scopus® The Canadian Journal of Soil Science (CJSS) dates back to 1957 and is one of the longest continuously operating soils journals in the world. Scopus® (www.scopus.com) is a large abstract and citation database owned by Elsevier B.V. It includes over 17,000 titles in the areas of physical, life, health and social sciences. Scopus® can track how often articles (for example from a particular author or journal) have been cited using its Citation Tracker function. A Scopus® search (accessed April 21, 2008) using CJSS as the ‘Source Title’ showed that the database included 1,585 CJSS documents published from 1974 to 2007. Inclusion of all articles published prior to 1996 is not guaranteed and ‘documents’ includes papers as well as prefaces, forewords, letters, errata etc. A check on CJSS documents published since 1996, showed that apart from the absence of 13 papers published in a Special Issue in 2001 (“Humic Substances in Soil and Related Environments”, Vol. 81, Issue 3) the database was accurate. Prior to 1996, accuracy declines with time. For example, from 1991-95, 86% of papers published by CJSS are included in the database. This falls to 66% for 1986-90, 58% for 1981-85 and only 19% for 1976-80. The Scopus® Citation Tracker estimated that the total number of citations received since 1996 for the 1,585 CJSS documents was 13,599. The most-cited CJSS paper was cited 228 times. Only 7 papers were cited >100 times while another 23 were cited from 50-99 times. At the other end of the scale, 14% of CJSS papers have yet to be cited, 11% have been cited once and 9% cited twice. If 2007 documents are excluded, since they are considered too ‘young’ to be cited, CJSS papers had a mean citation value of 9 times and a median value (more appropriate given the highly skewed dataset) of 4 times. However, because of papers missing from the database (especially prior to 1996), the above citation numbers have some degree of inaccuracy. The database was also searched for all articles that cited CJSS papers. There were a total of 10,461 citations of CJSS papers since 1996. The Soil Science Society of America Journal cited CJSS papers the most (553 times), followed by ourselves citing ourselves (i.e. CJSS papers citing other CJSS papers, 529 times). Rounding out the Top 10 journals citing CJSS papers were Soil Biology & Biochemistry (484), Soil & Tillage Research (361), Communications in Soil Science & Plant Analysis (303), Geoderma (267), Journal of Environmental Quality (248), Plant & Soil (228), Canadian Journal of Plant Science (202) and Biology & Fertility of Soils (197). The data showed that while CJSS papers are widely cited in other international journals, they are mostly cited by Canadian authors.

Improvement of the MERN calibration curve with adjusted soil N test values JOHN D. LAUZON*1, DAVID J. FALLOW1, KEN JANOVICEK2 AND KEVIN M. DUFTON1. 1

Department of Land Resource Science, University of Guelph, 50 Stone Road E Guelph, On, CA N1G 2W1 2 Plant Agriculture Department, University of Guelph, 50 Stone Road E Guelph, On, CA N1G 2W1 [email protected] Keywords: MERN, climate, soil N test The use of the soil nitrogen test (SNT) to determine the most economic rate of N fertilization (MERN) for corn has been used for many years in some parts of the world; however, it was not until 1991 that the SNT was calibrated for corn in southern Ontario (Kachanoski and Beauchamp, 1991). Since soil nitrate levels are known to change rapidly throughout the spring in Ontario, the reliability of the SNT is often questioned. A relationship was developed between SNT levels throughout the growing season and a estimate of the relative mineralization potential based on soil temperatures (Paul and Clark, 1989) and soil moisture (Greaves and Carter, 1920). Nine site years of intensively sampled soil nitrate data collected at the Elora Research station was used to develop this relationship. The results were used to adjust pre-sidedress soil nitrate test levels of 201 field sites in Ontario using SHAW model (Flerchinger and Saxton. 1989a) determined soil moisture and temperature data up to the point of soil sampling for each of the sites and years. Unadjusted and adjusted SNT levels were then compared to the MERN value found for each of the 201 corn nitrogen fertilizer response trials. Even though the relationship between change in SNT level and mineralization potential was based on the available Elora data set and not data from all regions in the province, adjusting the soil N test levels improved the correlation between sidedress soil nitrate level and MERN (r2 0.26 to 0.36). If regional soil and climate based information was available, adjusting soil test levels may result in a significant improvement in the ability of soil nitrogen test levels to be used to predict MERN.

References Flerchinger, G.N. and K.E. Saxton. 1989a. Simultaneous heat and water model of a freezing snowresidue-soil system I. Theory and development. Trans. of ASAE 32(2): 565-571. Greaves, J.E. and E.G. Carter. 1920. Influence of Moisture on the Bacterial Activities of the Soil. Soil Sci. 10: 361-387. Kachanoski, R.G. and E.G. Beauchamp. 1991. Nitrogen soil test for corn. Ontario Agriculture and Food Report, Department of Land Resource Science, University of Guelph, Guelph, ON. Paul, E.A., and F.E. Clark., 1989. Soil Microbiology and Biochemistry. Academic Press: San Diego, USA, p. 273.

Proposed classification system for anthropogenic soils in Alberta: Anthroposol Order LEONARD LESKIW1, M. ANNE NAETH2, DAVID S. CHANASYK2, HEATHER ARCHIBALD, SARAH CARTIER, ANDRE CHRISTENSEN, ANAYANSI COHENFERNANDEZ, SARA DUNNETT, INGRID HALLIN, TYREL HEMSLEY, MALLORY JACKSON, JILL VANDERGUST, NATE MEDINSKI, CANDACE NEMIRSKY, DUSTIN THEBERGE, BRENT WALCHUK 1

Paragon Soil and Environmental Consulting Inc., Edmonton, Alberta Department of Renewable Resources, University of Alberta, Edmonton, Alberta Other authors are land reclamation graduate and undergraduate students at the University of Alberta [email protected]

2

Keywords: reclamation, restoration, soil taxonomy, soil classification As Alberta continually develops its natural resources, a growing area of land is being disturbed and reclaimed in an attempt to emulate natural soils with a target goal of equivalent land capability. The need for a consistent soil classification system of these human made soils is apparent. Part of the difficulty in accurately describing the characteristics of these reclaimed soils is the broad use of terms that are not clearly defined, such as cover soil and overburden. A classification system for anthropogenic soils in Alberta will aid in the much needed standardization of terms used across the province and will allow professionals to efficiently communicate regarding these altered soils. The proposed system is similar to the Canadian System of Soil Classification in format and characterization of principal categories. The Anthropogenic Order is divided into Great Groups that reflect different topsoil characteristics, Subgroups that distinguish subsoil layers and Subgroup Modifiers that identify important soil characteristics.

Impacts of variable tree retention and substrate availability on soil diazotroph communities associated with Coastal Douglas-fir (Pseudotsuga menziesii ssp. menziesii) DAVID J. LEVY-BOOTH1 and RICHARD S. WINDER1 1

Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, 506 W. Burnside Rd., Victoria, B.C. V8Z 1M5 [email protected]

Keywords: nitrogen, disturbance, thinning, forestry

The sustainability of managed forest ecosystems depends on the continued functioning of soil microbial communities, such as those responsible for nutrient cycling. In Coastal British Columbian forest ecosystems, biological nitrogen fixation has been identified as an important target to assess ecological functioning of soil communities. We used a field trial and a microcosm experiment to assess the impacts of forest management practices, such as clear-cut and variable tree retention, on Coastal Douglas-fir (Pseudotsuga menziesii ssp. menziesii)associated soil diazotroph communities. We developed denaturing gradient gel electrophoresis (DGGE) and real-time PCR assays to examine the diversity and abundance of nitrogenase reductase (nifH) genes in forest plots that have been subjected to 0, 10, 70 and 100% tree retention in which coarse woody debris (CWD) was left on the forest floor. It is our aim to investigate the ability of CWD to maintain the nifH community. We also used a microcosm study to compare the nifH communities associated with Coastal Douglas-fir seedlings, forest litter and CWD. The diversity of universal nifH sequences was not significantly different between field treatment plots. DGGE and DNA sequencing indicated that abundant free-living diazotrophs in these plots were highly homologous to Azotobacter vinelandii nifH sequences. In winter 2008, at the Shawnigan Lake Levels of Growth Stock (LOGS) variable tree retention plantation, total C (%), total N (%) and NH4-N (ppm) correlated with the amount of Azotobacter sp. nifH sequences in the leaf-litter soil layer, with R2 values of 0.76 (P = 0.002), 0.55 (P = 0.022) and 0.47 (P = 0.040) respectively. In the leaflitter soil layer mean Azotobacter sp. nifH amounts were 4.04 ± 0.11 log Azotobacter sp. Genome Equivalents (AGE) g-1 in 10% tree retention plots, and 4.61 ± 0.10 and 4.47 ± 0.06 log AGE g-1 in 70 and 100% tree retention plots, respectively. Neither total nor Azotobacter sp., nifH abundance correlated significantly with substrate availability in mineral soils under field conditions. In initial microcosm studies, the amount of Azotobacter sp. specific nifH communities was also not significantly different in Douglas-fir, leaf-litter, or CWD-only treatments. These data suggest that there exists a seasonal relationship between the amount of carbon and nitrogen in leaf-litter of Douglas-fir forests and amounts of diazotrophic bacteria. Understanding the effects of substrate availability on the diversity and abundance of biological nitrogen fixing bacteria over several seasons will help in the creation of sustainable forest management practices that promote soil microbial community function in British Columbia’s forest soil ecosystems.

Re-localization from the ground up: the role of soils research in the foodshed analysis of the Bella Coola Valley DELISA LEWIS*1, ARTHUR BOMKE2, GARY G. RUNKA1 1

P.Ag., Land Sense Consulting, Bella Coola, B.C.; Associate Professor, UBC Faculty of Land and Food Systems; [email protected], Ph.D. candidate UBC Faculty of Land and Food Systems

2

Keywords: foodshed, re-localization, soil inventory In the Bella Coola Valley Foodshed Analysis project, we adopt a community-based approach to the identification of the potential agricultural resource-base with an explicit focus on inspiring greater productive capacity and enhanced local support. The investigation began with efforts to increase awareness of baseline soil resources and targeted community capacity development with this fundamental agricultural production factor. Two seasons of fieldwork in the valley focused on soil fertility testing, a detailed soil inventory and an agricultural land-use inventory with project design and methodology intended to include open workshops and return research findings to the community. We found a significant land-base from within the Bella Coola Valley of the highest capability soils and climate that would produce a wide range of agricultural and food crops. We also found strong evidence of actual food production and strong interest in extension information coupled with agricultural opportunities from within in the valley. The steps we have taken are preliminary, and require incremental capacity development at the local and provincial levels in order to secure a foothold of increased community participation in the production of foods. The Bella Coola Valley Foodshed project partners share the vision that this increased agricultural production, when carefully stewarded within the framework of the local resource base and inclusive of local residents, will provide crucially needed socio-economic and human health benefits.

Reference List (partial) Bertrand, R.A., Hughes-Games, G.A., and Nikkel, D.C. (1991). Soil Management Handbook for the Lower Fraser Valley. Abbotsford: B.C. Ministry of Agriculture, Fisheries and Food. British Columbia Ministry of Agriculture and Lands (2007). The British Columbia Agriculture Plan: Growing a Healthy Future for B.C. Families. Retrieved March 3, 2008, from http://www.al.gov.bc.ca/Agriculture_Plan/ British Columbia Ministry of Agriculture, Food and Fisheries (October, 2004). AGFOCUS-A guide to Agricultural Land Use Inventory. Retrieved March 13, 2007, from http://www.gov.bc.ca/agf/ under reports and publications. Fick, G.W. (June 21, 2007). Mapping “foodsheds” to meet nutritional needs; how local food systems can enhance healthy communities: 2006 Impact Statement. College of Agriculture and Life Sciences, Cornell University. Retrieved September 17, 2007, from http://research.cals.cornell.edu/entity?home=60&id=30895 Kloppenburg, J., Hendrickson, J., and Stevenson, G.W. (1996). Coming into the Foodshed, Agriculture and Human Values 13 (3), 33-42. Lang, T. and Heaseman M. (2004). Food Wars: the Global Battle for Minds, Mouths and Markets, London: Earthscan. Pojar, J., Klinka, K. and Demarchi, D.A. (1991). Chapter 6: Coastal Western Hemlock Zone. In D.Meidinger, and J. Pojar. (Eds.) Ecosystems of British Columbia, Victoria: B.C. Ministry of Forestry, Resource Branch.

Comparing different models for converting Cs-137 measurements into soil erosion rates estimates SHENG LI1,2

DAVID A. LOBB2

1

Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, Swift Current, SK, Canada 2 Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada [email protected] Keywords: Cs-137, conversion models, soil erosion Measurement of fallout Cs-137 has been widely used in soil erosion studies. Various conversion models were used to convert point Cs-137 measurements to point soil erosion rates. Walling and He summarized previous studies and proposed four conversion models for cultivated fields, one proportional model (PM) and three mass balance models (MBM-1, -2 and -3). To assess the applicability of these conversion models, Cs-137 redistribution was simulated with assigned tillage and water erosion rates at each sampling point along a hypothetical slope. The resulting Cs-137 data were converted to erosion rates using the conversion models and the estimated erosion rates were then compared to the erosion rates assigned. We found that the performances of the conversion models were largely dependent on the relative contributions of water versus tillage erosion. When tillage erosion dominated, MBM-1 worked well but MBM-2 substantially underestimated soil erosion. When water erosion dominated, MBM-2 worked well but MBM-1 substantially overestimated soil erosion. The PM estimates fell in between those of MBM-1 and MBM2. The MBM-3 provided the most accurate soil erosion estimates. However, the accuracy of MBM-3 estimates relied on the accuracy of the tillage erosion parameters used in the model.

Developing and validating soil erosion risk indicators for use on agricultural landscapes in Canada SHENG LI1,2

DAVID A. LOBB2

BRIAN MCCONKEY1

1

Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, Swift Current, SK, Canada 2 Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada [email protected] Keywords: NAHARP, SoilERI, WaterERI, WindERI, TillERI Soil erosion is a major threat to the sustainability of agriculture in Canada. The observed soil erosion pattern in agricultural land is a comprehensive result of all forms of soil erosion processes: tillage, water and wind erosion. A Risk of Soil Erosion Indicator (SoilERI) was developed in Canada through the National Agri-Environmental Health Analysis and Reporting Program (NAHARP). The SoilERI is an integration of tillage, water and wind erosion indicators (TillERI, WaterERI and WindERI). The TillERI is based on a more sophisticated tillage erosion model, the WaterERI is based on the Revised Universal Soil Loss Equation 2 (RUSLE2) and the WindERI is based on the Wind Erosion Equation (WEQ). The erosion indicators were applied to Soil Landscapes of Canada (SLC) polygon scale. Soil and climate data for each SLC polygon were extracted from the existing soil and climate databases. Representative landscape(s) were determined for each SLC polygon and each was divided into four segments: upper-, mid-, lower-slope and depression. 5-year interval crop rotations from 1981 to 2001 were extracted from Census Canada data. These data were used in the TillERI, WaterERI and WindERI to estimate tillage, water and wind erosion, respectively, on each segment on a given landscape. SoilERI was calculated as the sum of tillage, water and wind erosion on a given segment, and was integrated to the landscape and the SLC polygon levels. The preliminary results show that soil erosion decreased gradually overtime. Tillage and water erosion are the major contributors to total soil erosion, in which tillage erosion mainly causes soil loss on upper-slope segment and water erosion mainly causes soil loss in mid-slope segment.

Estimating soil erosion in Canada using repeated measures of Cs-137 radioactivity SHENG LI1,2

DAVID A. LOBB2

BRIAN MCCONKEY1

1

Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, Swift Current, SK, Canada 2 Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada [email protected] Keywords: repeated measures approach, traditional approach, Cs-137, soil erosion The Cs-137 measurements have been widely used to assess soil erosion across the landscapes. The traditional Cs-137 technique involves the use of a reference Cs-137 level, which is generally assumed to be uniform across the field site under investigation. The measured Cs-137 inventory at a given location is compared to the reference Cs-137 level and Cs-137 loss or gain is converted to soil loss or gain, respectively. The use of a single reference Cs-137 level is a major source of errors given the fact that ideal reference site is unavailable in most cases and the reference Cs-137 level is highly variable across the landscape. In addition, using the traditional method is an average soil erosion rate from about 1960 to the sampling date. This makes it difficult to relate the erosion estimation to the management practices, which has been changed significantly since 1960. In this study, two sets of samples were taken at the same locations over a period of about 4 and 7 years, respectively, at two sites located in Manitoba and Ontario, Canada. Average total soil erosion rates over the period from 1960 to the sampling dates were estimated using the traditional approach. Average total soil erosion rates between the two sampling dates were estimated by using the Cs-137 inventories of the first set of samples as the reference Cs-137 levels. It has been found that the patterns of all the erosion estimates for a given site were similar. The soil erosion rates estimated using the traditional Cs-137 technique was strongly affected by the reference level used. When accurate reference Cs-137 level is available, the two sets of erosion rates calculated using traditional approach matched up very well to each other. However, noticeable differences existed between the two approaches of Cs technique at the Manitoba site. The repeated measures approach better represents the current management and short-term erosion events occurred.

Comparing predictions of long-term soil carbon dynamics under various cropping management using K-model and CENTURY TAO LI1, XIAOMEI LI2, YONGSHENG FENG1 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2E3 Alberta Research Council, Edmonton, Alberta, T6N 2E4 [email protected]

2

Key Words: modeling, soil organic carbon, rotation, fertilizer, K-model, CENTURY There is a strong demand for accurate estimates of long-term changes in soil organic carbon (SOC) with different agricultural practices under different soil and climate conditions. A process and analytic model, K-model, including a non-compartmental algorithm of soil carbon decomposition, was developed to simulate the changes of SOC under different cropping and soil management practices. This study evaluates the performance of K-model by comparing its predictions on SOC with measurements and predictions of CENTURY model, which is widely used for similar purposes. Both K-model and CENTURY can predict the dynamics of SOC when site-specific soil and climate data are used to initialize simulations. Annual carbon decomposition rates simulated from single carbon pool of K-model and three carbon pools of CENTURY are almost same. However, compared with experimental measurements, K-model produces smaller root mean square errors and relative errors than CENTURY. When detailed site-specific soil and climate data are not available, K-model can still correctly predict the dynamics of SOC with its auto-correction function, but CENTURY produces poor results. In comparison with measurements, K-model has improved capacities to predict the effects of chemical fertilizer, manure application, residue management and fallow on SOC dynamics.

Two-dimensional DNA gel electrophoresis maps for separation and characterization of complex DNA mixtures from soil bacteria GUO-HUA LIU*1, TOSHIYUKI HARADA2, TAKASHI AMEMIYA2, KIMINORI ITOH1 1

Graduate School of Engineering, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan; 2 Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai ,Hodogaya-ku, Yokohama 240-8501, Japan. [email protected] Keywords: two-dimensional DNA gel electrophoresis, soil bacteria, characterization, 16S ribosomal DNA gene Genomic DNA profiles, such as denaturing gradient gel electrophoresis (DGGE) and terminal restrict fragment length polymorphism (T-RFLP), have commonly used in terms of separation and characterization of DNA mixture extracted from bacterial communities in environmental soil. Recently, a genomic technique, two-dimensional DNA gel electrophoresis (2-DGE, Fig.1), was also proved to resolve DNA mixture on the basis of size and content (Isshi and Itoh 2006; Liu and Itoh 2008). This technique can generate high-resolution DNA spot distribution images on polyacrylamide gels. The spot data can be used to estimate the bacterial diversity by Shannon index or Simpson index computed from the number of spots and the relative intensity of each spot. Moreover, a large number of detected individual operational taxonomic units (OTUs) from the high-resolution 2-DGE maps enable the assessment of differences in bacterial diversity in complex soil systems using rankabundance plots. Sample

Gel staining Chemical denaturing gradient gel (DGGE)

a

Chain length

Cap gel

b

c

GC content

Marker

d

Fig.1. Graphical representation of a fundamental 2-DGE mapping system. (a) Two same DNA samples are separated into two lanes by size on a nondenaturing polyacrylamide gel, one of which is stained with SYBR Green I to confirm length-dependent pattern and another of which is used to analyze for 2-DGE. (b) The gel strip for 2-DGE analysis is excised from the first dimension gel and transferred to the top of a chemical denaturing gradient gel and then DNA fragments are separated on the basis of melting characteristics. (c) The chemical denaturing gradient gel is stained, washed and dried. (d) Photograph of gel on UV Transillumination device for generating a spot distribution map. Reference List Isshi, T., Rajendran, N., Amemiya, T., and Itoh, K. 2006. Development of a two-dimensional electrophoresis method to study soil bacterial diversity. Soil Sci. Plant Nutr., 52: 601–609. Liu, G. H., Amemiya, T. and Itoh, K. 2008. Two-dimensional DNA gel electrophoresis mapping: a novel approach to diversity analysis of bacterial communities in environmental soil. J. Biosci.Bioeng. 105: 127-133.

Soil microbial community response to controlled-release urea in western Canada N.Z. LUPWAYI1, Y.K SOON1, G.W. CLAYTON2, S. BITTMAN3, S.S. MALHI4 AND C.A. GRANT5 Agriculture & Agri-Food Canada 1 Beaverlodge, Alberta 2 Lethbridge, Alberta 3 Agassiz, British Columbia 4 Melfort, Saskatchewan 5 Brandon, Manitoba [email protected] Keywords: conservation tillage, microbial biomass, microbial diversity, fertilizer Soil microorganisms mediate many important biological processes for sustainable agriculture. The effects of controlled-release urea (CRU), applied at recommended rates, on soil microbial biomass and diversity were studied at six sites across western Canada from 2004 to 2006. Fertilizer treatments were CRU, regular urea and an unfertilized control. A treatment on timing of fertilizer application (fall vs. spring) was included in 9 of the 18 site-years. A barley (or wheat)-canola-wheat (or barley) rotation (continuous silage corn at Agassiz) was established under conventional tillage (CT) or zero tillage (ZT). The fertilizers were side-banded at 50-60 kg N ha-1 for wheat, barley and canola, and broadcast at 150 kg N ha-1 for corn. Microbial biomass C (MBC) and the functional diversity of soil bacteria were determined in crop rhizosphere and bulk soil at the flagleaf stage of cereal growth (anthesis stage for corn) or flowering stage of canola growth. In the rhizosphere, there were no fertilizer effects on MBC or bacterial diversity in 94% and 72% of the site-years, respectively. In bulk soil, the corresponding percentage was 78% in both cases. Where fertilizer had significant effects, both CRU and urea increased soil MBC or bacterial diversity. CRU increased MBC or bacterial diversity more than urea in three site-years, but the reverse was observed in one site-year. Time of fertilizer application had no effects on MBC or bacterial diversity in 89% and 78% of the site-years, respectively, in the rhizosphere, and no effects at all in bulk soil. Fall-applied fertilizer increased MBC more than spring-applied fertilizer in one site-year, but the reverse occurred for bacterial diversity in two site-years. Tillage had no significant effects on soil microbial biomass or diversity in 78-94% of the site-years in the rhizosphere or bulk soil, and significant effects were usually in favour of ZT. Interactions between fertilizer and tillage on MBC or bacterial diversity were observed in only one and two site-years, respectively. Shifts in bacterial community structures due to fertilizer type, time of application, and tillage were sometimes observed where the treatment effects described above were not significant. Therefore, in a wide range of environmental conditions in western Canada, fertilizer application had no significant effects on soil microorganisms in most cases, but CRU tended to increase soil MBC or diversity more than urea when effects were significant. This means that CRU applied at recommended rates probably does not have negative effects, and may even have positive effects, on soil biological processes.

Soil formate regulates the fungal nitrous oxide emission pathway WAI K. MA*1, RICHARD E. FARRELL1, STEVEN D. SICILIANO1 1

Department of Soil Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8 [email protected] [email protected] Keywords: denitrification, formate, fungi, N2O, nitrification Fungal activity is a major driver in the global nitrogen cycle, and mounting evidence suggests fungal denitrification activity contributes significantly to soil emissions of the greenhouse gas nitrous oxide (N2O). The metabolic pathway and oxygen requirement for fungal denitrification is different from bacterial denitrification. We hypothesized that soil N2O emission from fungi is formate and O2dependent and that land-use and landforms would influence the proportion of N2O coming from fungi. If fungi are using the formate pathway to form N2O, then a particular fungal gene (P450nor) will be linked to N2O emissions. Using substrate-induced respiration inhibition (SIRIN) under anaerobic and aerobic conditions in combination with 15N gas analysis, we found that formate and hypoxia (vs. anaerobiosis) was essential for fungal reduction of 15N-labeled nitrate to 15N2O. As much as 65% of soil emitted N2O was attributable to fungi; however, this was only found in soils from wateraccumulating landforms. These water-accumulating landforms had lower fungal biomass but greater P450nor genotype prevalence and a fungal community composition that differed from upland landforms. This study has demonstrated the importance of fungi to N2O emissions in the prairie landscape and identified the putative genotype responsible for these emissions.

NH3 volatilisation following urea application: influence of tillage system and method of application JAMES D. MACDONALD1, PHILIPPE ROCHETTE1, DENIS ANGERS1, MARTIN CHANTIGNY1, MARC-OLIVIER GASSER2, NORMAND BERTRAND1 1

Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd, Québec, QC, Canada, G1V 2J3 2 Institut de recherche et développement en agroenvironnement, Québec, Canada, G1P 3W8 [email protected] Keywords: volatilization, urea, swine manure, no-till Urea is a relatively inexpensive nitrogen fertilizer and is commonly applied to no-till tillage systems in Quebec by a broadcast application shortly after seeding. Urea is prone to N-loss through volatilization and there is evidence that NH3-N loss is increased on no-till soils (Al-Kanani 1992; Palma et al. 1998). Incorporation is thought to be an effective method of reducing NH3-N loss (Sommer 2004). In June of 2006, an experiment was developed to measure NH3-N loss from a no till soil (Le Bras series, silty loam) with a surface broadcast application of urea compared to application in shallow bands. Emissions from broadcast urea were extremely high, with losses of 64% of applied N. Banded urea however, still lost 31% of applied N. Due to the surprisingly high loss of NH3-N from the banded urea, in June 2007, a second experiment was developed to compare NH3-N loss from the Le Bras soil under conventional tillage with different application methods: surface broadcast, band incorporation and surface broadcast followed by shallow incorporation. In this case, banded application lost the greatest proportion of applied N (27%) followed by incorporation (16%), and surface broadcast (9.5%). The exceptionally high N loss from broadcast urea applications in 2006 were due to very high concentrations of urease in the surface of the no-till soils (288 µg NH4-N g-1 h-1) and abundant organic material on the surface that aided in transferring moisture to urea granules. Tilled soils in 2007 had five times less urease (55 µg NH4-N g-1 h-1) and the dry exposed mineral surface of the tilled soil was less conducive to dissolution and hydrolysis of urea. Incorporation of broadcast urea into the moister underlying soil aided in granule dissolution and consequently increased volatilization relative to the surface application. Volatilization from banded urea was identical in 2006 and 2007 and high NH3 emission rates were due to the creation of a zone of very high pH (8.7) in conjunction with very high concentrations of NH4. The results clearly demonstrate that surface broadcasting of urea to no-till soils should be avoided. Furthermore, banding of urea increased NH3-N loss in this case, suggesting that banding should only be used as a method of reduction of volatilization on soils with high buffer capacities.

Reference List Al-Kanani, T. and MacKenzie A.F. 1992. Effect of tillage practices and hay straw on ammonia volatilization from nitrogen fertilizer solutions. Can. J. Soil Sci. 72: 145-157. Palma, R.M., Saubidet, M.I., Rìmolo, M., and Utsumi, J. 1998. Nitrogen losses by volatilization in a corn crop with two tillage systems in the Argentine pampa. Commun. Soil Sci. Plant Anal. 29: 28652879. Sommer S.G. Sshjoerring, J.K. and Denmead, O.T. 2004. Ammonia emission from mineral fertilizers and fertilized crops. Adv. Agron. 82: 557-622.

Returning forage fields to an annual rotation: Short-term carbon and nitrogen dynamics JAMES D. MACDONALD1, MARTIN CHANTIGNY1, DENIS ANGERS1, PHILIPPE ROCHETTE1, ISABELLE ROYER1, MARC-OLIVIER GASSER2 1

Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd, Québec, QC, Canada, G1V 2J3 2 Institut de recherche et développement en agroenvironnement, Québec, Canada, G1P 3W8 [email protected] Keywords: carbon, inversion tillage, water soluble carbon, meadow Forage fields are often fertilized several times a year with animal slurries because their rapid growth can immobilize nutrients. As a consequence many forage fields in Quebec have become very nutrient rich. As these fields are reintegrated into annual crop rotations, there is a strong possibility of release of nutrients and carbon to the environment. The purpose of this work was to monitor the short-term dynamics of C and N during the cultivation of an old grassland. In the fall of 2007, two long-term research plots were divided into 24 subplots (3 treatments x 4 replicates x 2 long-term plots) that were either cultivated by inversion tillage, chemically treated with herbicide or left as controls (grass, undisturbed). One of the two long-term plots had received large doses of liquid swine manure (LSM) annually since 1978 (100m3 ha-1) and the other was an unmodified grassland (0 m3 ha-1). The plots had been managed as typical forage fields since 1978, seeded to Timothy and turned and renewed every 7 years. After the plots were established and treated, static chambers were installed to measure soil gases: CO2 and N2O and tension lysimeters were installed to monitor dissolved carbon and nitrogen in the soil solution. Repeated soil samples were taken to monitor changes in total and mineral nitrogen and total and water extractable carbon and microbial biomass on the soil solid phase. Surprisingly soil respiration was higher on the unmodified grassland than the fertilized grassland. In both cases the cumulative emissions of CO2 were 30 and 18% lower, respectively, in the subplots that had undergone inversion tillage compared to the subplots that were treated by herbicide. On the unmodified grassland, mineral N was largely in the form of NH4+ (on average 80%), emissions of N2O were minimal and concentrations of N in solution were low (>3 mg l-1) of which roughly 50% was dissolved organic N. There was little difference among treatments, and virtually all N liberated through decomposition was immobilized and retained in the soil system. To the contrary, on the fertilized grassland in the herbicide and tillage subplots, mineral N in the upper 30 cm of the soil was on average 80% in the form of NO3- and roughly 25 to 50% of the mineral N present in the soil was in solution. Emissions of N2O throughout the fall season were 1.0 and 0.8 g m-2 for the herbicide and tillage subplots respectively. Through N2O emissions and leaching through the soil profile, roughly 80% of N mineralized was lost from the system. The fall cultivation of a grasslands with a history of fertilization with animal slurries resulted in a very large burst of N into the environment through gaseous emissions and leaching of mineral N through the soil profile. Tillage did not increase net N loss, but actually decreased gaseous N2O losses. Carbon loss was greater on the unfertilized prairie and was reduced by inversion tillage.

Impact of pedogenesis on the distribution of trace and heavy metals in Saskatchewan soils ABHISHEK MANDAL*, DARWIN ANDERSON , DEREK PEAK Department of Soil Science University of Saskatchewan 51 Campus Drive Saskatoon , SK S7N 5A8 Abhishek Mandal Keywords: Trace metals, heavy metals, illuviation, carbonates, glacial till The objective of this initial study is to assess the impact of pedogenesis on the distribution of trace and heavy metals in soils. A toposequence of soils on a hummocky till landscape in the Moist Mixed Grassland Ecoregion of central Saskatchewan was studied. Luvic Gleysols with pronounced eluvial (Aeg) and illuvial (Btg) horizons in the depression, were compared to Rego Black Chernozems on very gentle slopes adjacent to the depression. Secondary calcium carbonate accumulates in the Rego soils around the depressions. Soil samples of different horizons were collected and the concentration of various trace and heavy metals were measured by ICP/MS to assess the impact of pedogenesis on their distribution, within profiles and within the toposequence. Relatively constant ratios of zirconium to titanium indicate a general similarity of parent material, glacial till or local alluvial or eolian materials derived from the till. Phosphorus contents in C horizons were similar to those reported for glacial deposits in Saskatchewan, with marked loss of phosphorus from eluvial horizons. Several elements, zinc, vanadium and chromium for example, are reduced in eluvial horizons, with higher concentrations in illuvial B horizons indicating an association with clay. Several divalent cations such as manganese, strontium and nickel are at lower concentrations in the A and B horizons, with higher concentrations in Cca horizons. Co-precipitation with calcite minerals is suggested as a possible mechanism for nickel and manganese, not for strontium. Arsenic, an oxyanion like phosphorus, is slightly reduced in strongly eluvial horizons, highest in Btg horizons. This initial work indicates that many trace and heavy metals are redistributed by pedogenetic processes, and that an understanding of their chemical properties adds to our understanding of their redistribution.

Comparative effects of different concentrations of NaCl, Na2SO4 and NaHCO3 salts on growth parameters of 4 wheat cultivars FARBOODI MANOOCHEHR1, SIADAT HAMID2 1

Assistant Professor of Islamic Azad University- Miyaneh Branch Professor of Islamic Azad University- Science and Research Branch [email protected]

2

Keywords: wheat, salinity tolerance, threshold, modeling Furthermore the general effects of salinity which studied by different concentration of NaCl salt, in a RCB design the special effects of Cl- , SO4-2 and HCO3- were notified on growth parameters and the response of 4 wheat genotypes were determined. After germination at seedling growth stage the different concentrations Na2SO4 and NaCl salts (0,75,150 and 225 mmol.L-1) with and without of CaCl2 were added to %50 Hoagland solution (Hoagland and Arnon, 1950), and were used as complementary treatment solutions for evaluating growth parameters and determining tolerance threshold and S50 quantity for seedling stage of 4 wheat (T.aestivum L.) cultivars. In each plot 4 seeds of each genotype were disinfected by fungicide and were placed in a 9 cm diameter pot containing perlite with <1 mm diameter. The pots were placed in a growth chamber with (20±2C and RH=85%) and irrigated for two days with Hoagland solution and then with saline solution treatments every 24 hours. After 10,20,30,40, and 50 days the plants sampled, The fresh and oven dried matter weights of roots and shoots were weighted and total dry matter (TDM) were determined. Finally leaf area (LA) and free proline (Pr) were measured by Bates method (Bates and Tear 1973). The Na2SO4 salt had less negative effect on TDM, LA and Pr than NaCl and NaHCO3. Bicarbonate decreased LA more than chloride and sulphate respectively. Generally, with increasing concentration of each salt in solution TDM and LA decreased and the starting time of flowering delayed .The linear, exponential and polynomial regression analysis used for calculation of the salinity tolerance threshold, (S10) and economic loss threshold (S50) calculated for different types of salinity and different genotypes. The S10, S50 and the slope of linear regression (b) were used as relative salinity tolerance classification. Also salinity tolerance parameters such as salinity threshold (S10) and economic loss threshold (S50) were calculated by regression analysis models. The Na2SO4 salt had less negative effects than NaCl and NaHCO3. Bicarbonate decreased roots and shoots weight more than chloride and sulfate, respectively. Finally, total dry matter (TDM) had most variability with salinity and genotype and was the best variable for screening of these genotypes.

Impact of forest harvesting on soil microbial community dynamics and nutrient availability ASHLEY C. MASCARENHAS*1, JAMES J. GERMIDA 1 1

Department of Soil Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8 [email protected]

Keywords: nutrients, CLPP, PLFA, microbial community, lodge-pole pine Forests are an important economic resource for Canada. Little is know, however, about how current harvesting practices impact on the sustainability of these ecosystems, specifically as it relates to biogeochemical cycles and the microbial communities that influence nutrient transformation key to these cycles. The objective of this study was to assess microbial community dynamics and plant available nutrient levels in the soil of 5 different aged lodgepole pine dominated stands within the Boreal Plain ecozone. Plots were established at sites of 0.25, 1, 2, 3 and 77 yrs post harvest age and sampled at two time intervals. Microbial communities at these sites were measured using community level physiological profile (CLPP) and phospholipids fatty acid (PLFA) analysis. The CLPP and PLFA analysis indicated that microbial communities were significantly different between sites at both the beginning and end of the sampling season. Additionally, within an individual site, there were significant differences between microbial communities present in the soil at the beginning and end of the sampling season. Plant available nutrient levels were measured in the LFH and mineral soil horizons at two time intervals using plant root simulator (PRS) probes. Nutrient data analysis revealed that total available N and ammonium (NH4-N) levels were significantly different between sites, whereas nitrate (NO3-N) and P levels were not different. Overall, these results suggest that forest harvesting altered the microbial community dynamics and nutrient fluxes within both the LFH layer and the mineral soil.

Greenhouse gas emissions and nitrogen cycling in Saskatchewan boreal forest soils AMANDA L. MATSON*1, DAN J. PENNOCK1, ANGELA BEDARD-HAUGHN1 1

Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N5A8; [email protected] Keywords: nitrous oxide, methane, boreal forest, isotope dilution Despite the spatial significance of Canada’s boreal forest, there is very little known about greenhouse gas emissions within it. The primary objective of this project was to study the atmosphere-soil exchange of CH4 and N2O in the boreal forest of northern Saskatchewan. In the summers of 2006 and 2007, greenhouse gas emissions were measured along transects in three different mature forest stands (aspen, black spruce and jack pine) using a sealed chamber method. In addition, the gross rates of mineralization and nitrification, and the relative contributions of nitrification and denitrification to N2O emissions, were measured using a stable isotope technique. 15N-enriched nitrate and ammonium were injected into intact soil cores and the amount of 15N found in the different N pools (nitrate, ammonium and N2O) was used to determine the mineralization and nitrification rates as well as which process contributed most significantly to total N2O emissions. Results indicated that the jack pine and black spruce sites were slight sinks of CH4, whereas the aspen site was a net source. All three sites had very low cumulative N2O emissions (between -0.02 and 0.14 kg N2O-N ha-1 yr-1 in both years). At the aspen site, the drier uplands were the primary source of N2O emissions, which the 15N indicated was due to a nitrification-related process. The moist depressions were the primary source of CH4, and also emitted some N2O, which 15N measurements indicated were denitrification-related.

Convergence of food, fuel and fiber: future of soil organic matter? WILLIAM B. MCGILL College of Science and Management University of Northern British Columbia 3333 University Way, Prince George, BC V2N 4Z9 [email protected] Keywords: soil organic matter; food, fuel, fiber, biomass energy Growth of economies in Asia, especially in China and India is increasing the demand for Energy. Population growth and growing wealth are increasing demand for food or the commodities from which food is made. Fiber and food are land-based commodities and are increasingly meeting part of the demand for energy. Such convergence of food, fuel and fiber will produce new competition for land use. Land will be used for the highest value use, so will demand for energy drive conversion of land from food or fiber production to biomass energy crops? Will materials that are now left in forests or on farm fields be harvested for biomass energy? Will materials such as slash, manure or other organic by-products that are now returned to soils be diverted for biomass energy? Will soil organic matter be depleted as a result? What will happen to food supply and price?

Fungal and soil inoculation influence on seedling growth and survival of Black Huckleberry (Vaccinium membranaceum Douglas ex Torr.) and Velvet-Leaf Huckleberry (Vaccinium myrtilloides Michx.) IRENE M. MCKECHNIE*1, HUGUES B. MASSICOTTE1, PHILIP J. BURTON1 1

Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, Canada, V2N 4Z9

[email protected] Keywords: ericoid mycorrhizas, huckleberry, inoculation, Vaccinium membranaceum,

Vaccinium myrtilloides Plants in the order Ericales, including Vaccinium species, occur worldwide, often growing under harsh, nutrient-poor conditions. Although much is known with respect to the cultivated species V. corymbosum L., the biology and propagation requirements of northern Vaccinium species and their potential for use in reclamation, restoration, and horticulture is unexplored. In this study, three seed provenances each of V. membranaceum and V. myrtilloides were collected and sown on a 60:40 peat:sand mixture. Seedling emergence began 25 days after the sowing date. Seedlings were kept in a controlled environment with 21°/10°C day/night temperature and a 15 hour photoperiod. Subsequent to germination, one-third of the seedlings were inoculated with a mixture of ericoid mycorrhizal fungi: Rhizoscyphus ericae (DJ Read) WY Zhuang & Korf, Oidiodendron maius Barron, and Meliniomyces sp. Another one-third of the seedlings were inoculated with a soil dilution using soil originating from natural Vaccinium habitat. The final one-third of the seedlings were maintained as a control group. In the summer of 2008, seedlings will be planted in garden trials; growth (measured as dry biomass production) and survival will be compared at the end of the growing season. Preliminary results will be presented on germination and survival rates under greenhouse conditions, and on the presence or absence of mycorrhizal colonization following inoculation.

Reduced flooding incidence on soil fertility in the Peace-Athabasca River Delta FRED K. MENSAH1, JEFFREY J. SCHOENAU2 1

Golder Associates Ltd. EA Reclamation, Calgary, AB; University of Saskatchewan, Soil Science Dept., Saskatoon, SK. [email protected]

2

Keywords: supply rate, denitrification, mineralization, immobilization The basins of the Peace-Athabasca Delta (PAD) in north-eastern Alberta represent one of Canada’s most important wetland ecosystems. The PAD contains highly productive habitats with abundant emergent and submergent vegetation which are important for the survival of waterfowl, and numerous ungulates. The regulation of the Peace River through the WAC Bennett dam has caused changes in the hydrological regime of the area. Reduced over-bank flooding results in drier soil conditions, which in turn affect nutrient cycling and ultimately influence plant and animal communities in the area. The objective of this study was to examine how a change in water levels and soil temperature could potentially affect nutrient turnover in delta basin soils. Cored soil samples from a T-transect across a typical delta basin wetland - Jemis Lake (Jaques, 1990) were subjected to variations in water levels and temperature under controlled conditions, and measuring the nutrient release rates in the soils. Only data collected at 5cm depth is reported in this poster. Reference List Prowse, T.D., Lalonde, V. 1996. Open-Water and Ice-Jam Flooding of a Northern Delta. Nordic Hydrology 27, 85-100pp. Jaques, D.R. 1990. Vegetation habitat types of the Peace-Athabasca Delta: 1976-1989. Ecosat Geobotanical Surveys Inc. for Parks Canada, Wood Buffalo Nstional Park, 46pp. Environment Alberta (http://www3.gov.ab.ca/env/water/nrbs/sec1/sect14.html) Northern River Basins Study Final Report – The Peace-Athabasca Delta.

Do freeze-thaw cycles enhance water soluble phosphorus in the top-soil of conservation tillage? AIMÉ J. MESSIGA*1,3, NOURA ZIADI1, CHRISTIAN MOREL2, LÉON E. PARENT3 1

Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd., Quebec, G1V 2J3 Institut National de la Recherche Agronomique, UMR TCEM, BP 81, 33883 Villenave d’Ornon cedex, Bordeaux, France 3 Department of Soil and Agri-Food Engineering, Laval University, Quebec, G1K 7P4 2

[email protected] Keywords: freeze-thaw cycles, water extractable P, P management. Simulating different scenarios of freeze-thaw cycles becomes important to understand and predict the long term effects of climatic change on agricultural practices in temperate regions (Henry, 2007). We hypothesized that winter freeze–thaw cycles enhance P released by crop residues, hence waterextractable P in the uppermost layer of a Gleysol under no-till. Intact soil cores were collected in autumn 2007 using metal cylinders (5 cm in height and 4.5 cm in diameter) from a long term maizesoybean rotation experiment located in Quebec. Soybean residues (2 g) were added onto soil surface and the cores were submitted to various freeze-thaw cycles for 60 consecutives days. The freeze-thaw cycles were adapted from Bechmann et al. (2005): (1) 50 days freezing at -18 °C and 5 days thawing at 10 °C; (2) 6 cycles of 5 days freezing at – 18 °C and 5 days thawing at 10 °C; (3) 3 cycles of 5 days freezing at – 18 °C and 5 days thawing at 10 °C; (4) 1 cycle of 5 days freezing at – 18 °C and 5 days thawing at 10 °C; (5) 60 days incubation at 4 °C. After each cycle, water extractable P (Pw, Sissingh, 1971), Mehlich-III P (PM-III), and soluble carbon were determined in one-cm thick soil slices. Preliminary results show that, under the simulated freezing and thawing cycles, Pw and PM-III contents in the uppermost layer of no-till soil were higher compared to conventionally till soil. Averaged over the whole core soil, water extractable P varies from 30 mg kg-1 soil in the conventional tillage to 50 mg kg-1 soil in the no-till soil during the first and third cycles. The effects of freezing and thawing on plant residues occurred after the 6th cycle where Pw in the first 3 cm of no-till + residues treatment increased by two-folds reaching 100 mg P kg-1 soil. We concluded that increasing the number of freeze-thaw cycles enhances Pw in no-till soil as a result of P released by crop residues. Reference List Bechmann, M., Kleinman, P. J. A., Sharpley, A. N. and Saporito, L. L. 2005. Freeze-thaw effects on phosphorus loss in runoff from manured and catch crop soils. J. Environ. Qual. 34: 2301–2309 Henry, H. A. L. 2007. Review. Soil freeze–thaw cycle experiments: Trends, methodological weaknesses and suggested improvements. Soil Biology & Biochemistry 39 : 977–986. Sissingh, H. A. 1971. Analytical technique of the Pw method used for the assessment of the phosphate status of arable soils in the Netherlands. Plant Soil 34: 483–486. Reference List Prowse, T.D., Lalonde, V. 1996. Open-Water and Ice-Jam Flooding of a Northern Delta. Nordic Hydrology 27, 85-100pp. Jaques, D.R. 1990. Vegetation habitat types of the Peace-Athabasca Delta: 1976-1989. Ecosat Geobotanical Surveys Inc. for Parks Canada, Wood Buffalo Nstional Park, 46pp. Environment Alberta (http://www3.gov.ab.ca/env/water/nrbs/sec1/sect14.html) Northern River Basins Study Final Report – The Peace-Athabasca Delta.

Water-soluble phosphorus in soil aggregates as influenced by tillage practices AIMÉ J. MESSIGA*1,3, NOURA ZIADI1, CHRISTIAN MOREL2, LÉON E. PARENT3, DENIS A. ANGERS1 1

Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd., Quebec, G1V 2J3 Institut National de la Recherche Agronomique, UMR TCEM, BP 81, 33883 Villenave d’Ornon cedex, Bordeaux, France 3 Department of Soil and Agri-Food Engineering, Laval University, Quebec, G1K 7P4 2

[email protected] Keywords: Water extractable P, soil aggregation, no-till, conventional tillage Relating water extractable P (Pw) and soil aggregation could improve our understanding of P transformations under no-till systems and help to improve management strategies aiming at reducing P transport from agricultural soils to surface water. We hypothesized that in the uppermost layer (0-5 cm) of a Gleysol under long term no-till system, Pw content would increase with aggregate size. Field moist soil (< 6 mm) was collected from conventional tillage and no-till systems in long term maizesoybean rotation experiment in Quebec. After aggregate-size separation by wet-sieving, Pw (Sharpley et al., 2007) and Mehlich-3 P (PM-III) were determined on macro-aggregates (2000 – 250 µm), mesoaggregates (250 – 180 µm), micro-aggregates (180 µm – 53 µm), and silt + clay (< 53 µm) particles. Macro- and meso-aggregates were more abundant in no-till compared to conventional tillage system. The Pw and PM-III contents increased from the silt + clay particles towards the meso- and macroaggregates in no-till while no real trend was observed in the conventional tillage. These preliminary results show that P accumulation in the uppermost layer of no-till soil mainly occurs in the least transportable aggregate size fractions. P Sorption characteristics of the aggregate size fractions will be studied to allow a more objective conclusion. Reference list Sharpley, A. N., Kleinman, P. J. A. and Weld, J. L. 2007. Environmental soil phosphorus indices. Pp. 141-159. In Soil Sampling and Methods of analysis. Carter, M.R., and Gregorich, E.G., (2nd eds).

Influence of fresh and composted manure on barley yield, soil nitrate leaching, and denitrification JIM J. MILLER1, BRUCE BEASLEY1, CRAIG DRURY2, AND BERNIE ZEBARTH3 1

Agriculture and Agri-Food Canada, 5403-1st Ave. South, Lethbridge, AB., T1J 4B1 2 Agriculture and Agri-Food Canada, Harrow, ON 3 Agriculture and Agri-Food Canada, Fredericton, NB [email protected] Keywords: manure, compost, barley yield, nitrate leaching, denitrification A nine-year field experiment was initiated in 1998 to compare the influence of fresh manure (FM) versus composted (CM) beef manure on barley yield and soil nutrient cycling (N, P). The experiment consists of annual applications of increasing rates (13, 37, 77 Mg dry manure ha-1) of FM and CM. There is also an unamended control (CON). Preliminary results indicate that there was no significant (P > 0.05) difference in barley yield between FM and CM after one to five years of annual amendment application, and then barley yields were significantly (P ≤ 0.05) greater for CM than FM after six to eight years of annual application. Nitrate-N leaching was similar after one year of application, and it was generally greater for FM than CM for deeper depths (60-150 cm) after three, six and eight years of application. The total mass of nitrate-N in the soil profile (0-150 cm) was similar throughout the years for FM and CM, however, the total mass was significantly greater for FM than CM after three and eight years. Mean daily denitrification rates from June 12 to September 25, 2007 were greatest under FM, followed by CM and the CON, but there was no significant difference in emissions between FM and CM. Our preliminary results indicate that composted beef cattle manure has no disadvantages compared to fresh manure with respect to crop yields, nitrate leaching, and denitrification.

Watershed evaluation of beneficial management practices (WEBs) in the lower Little Bow Basin of southern Alberta JIM. J. MILLER1, DAVID CHANASYK2, TONY CURTIS1, ANDREA KALISCHUK3, DENNIS LASTUKA4, MURRAY LEWIS4, BARRY OLSON3, SHANE PETRY5, DWAYNE ROGNESS6, CARLYLE ROSS7, KIM SCHMITT8, ELWIN SMITH1, JANELLE VILLENEUVE3, and WALTER WILLMS1 1

Agriculture and Agri-Food Canada, 5403 1st Ave. South, Lethbridge, AB., T1J 4B1; University of Alberta, Edmonton, AB; 3 Alberta Agriculture and Rural Development, Lethbridge, AB; 4 Agriculture and Agri-Food Canada, PFRA, Lethbridge, AB; 5 Department of Fisheries and Oceans, Lethbridge, AB; 6 County of Lethbridge, Lethbridge, AB; 7 Agriculture and Agri-Food Canada, Edmonton, AB; 8 Ducks Unlimited, Red Deer, AB [email protected] 2

Keywords: BMPs, watershed, water quality, river The Lower Little Bow Watershed (2565 ha) in Alberta is one of seven WEBS watersheds across Canada. This watershed is dominated by native grassland with cow-calf operations, irrigated and dryland crops, and intensive livestock operations. Five BMPs are being evaluated in this watershed. They include streambank fencing, off-stream watering with no fencing, conversion to greencover, grass and mixed grass-shrub buffers, and manure management. The major water quality parameters evaluated were sediment (TSS), nutrients (TN, TP) and bacteria (E. coli). Preliminary results indicate that streambank fencing is generally effective at maintaining water quality for TSS, TN, TP, and E. coli; and riparian health is dramatically improved. Exclusion grazing did not improve runoff quality compared to grazed pastures, suggesting direct fecal contamination of the river was more likely than runoff from adjacent land. In contrast, the effectiveness of off-stream watering with no fencing depended on the variable of interest, and the riparian health was slightly improved. Off-stream watering systems were found to be nutrient hot-spots for N and P. However, it may be better to have nutrients accumulate away from than adjacent to rivers, and portable watering systems may help to alleviate hot-spots. Little or no runoff into grass buffers located on flat sandy soils adjacent to the river indicated that buffers in this watershed are not required. Grass buffers were not more effective at filtering runoff than barley because of the continuous seed rows of barley perpendicular to the direction of runoff flow. Mixed grass-shrub buffers were ineffective because of soil disturbance and trapping of soil by the plastic mulch. Conversion from barley to alfalfa did not improve runoff quality; and may be related to the greater surface residue or mulch present under barley. Applying manure based on P instead of N reduced certain dissolved forms of P. Although TP in runoff was not significantly reduced by applying manure based on P, there was a nonsignificant trend for lower TP in runoff under P than N application.

Harvesting and slash piling affects soil respiration, soil temperature, and soil moisture regimes in Newfoundland boreal forests MARTIN T. MORONI1, PAUL CARTER1, DARRELL HARRIS1, DANIEL RYAN2 1

Affiliation and address; Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, Corner Brook, Newfoundland and Labrador. P.O. Box 960, Corner Brook, NL, A2H 6J3 2 Affiliation and address; Department of Mathematics and Statistics, University of Prince Edward Island, Charlottetown, Prince Edward Island, C1A 4P3 [email protected] Keywords: soil respiration, boreal, harvest, slash The impact of harvesting and slash piling on soil temperature, soil moisture, and soil respiration was examined in a balsam fir (Abies balsamea) and a black spruce (Picea marinara) forest located in western Newfoundland, Canada. Within 4 mo of harvesting, soil temperature, moisture, and soil respiration rates were affected by harvesting and slash piling. Clearcut areas without slash (CC-S) had significantly lower soil respiration rates than uncut forests (F). However, clearcut areas with slash cover (CC+S) had significantly higher soil respiration rates than CC-S. When harvested areas with and without slash were combined, harvesting decreased soil respiration in the black spruce forest but had no effect on soil respiration in the balsam fir forest. Harvesting increased soil temperatures at 10 cm, however CC+S temperatures were cooler than CC-S temperatures. Soil moisture levels at >3.5 cm were not significantly depleted. However, there was evidence of soil drying at <3.5 cm. Soil temperature (at 10 cm) at the time of measurement was most strongly correlated to rates of soil respiration. When variations in soil respiration were adjusted for 10-cm soil temperature, temporal variability, and treatment effects (harvesting and slash piling) played a minor role in explaining soil respiration rates. Soil moisture levels (3.5–9.5 cm depth) also played a minor role in explaining soil respiration rates. Soil respiration may be separated into heterotrophic and autotrophic components.

The influence of different N-fertilizers on DOC and DON of two Alfisols in north of Iran MONA MOSSADEGHI*1, AMIR LAKZIAN2, GHOLAM H. HAGHNIA3 1

M.Sc. Student of Ferdowsi university Of Mashad Associated Prof. of Ferdowsi university Of Mashad 3 Prof. of Ferdowsi university Of Mashad *[email protected] 2

Keywords: N-fertilizers, DOC, DON, DIN Dissolved Organic Matter (DOM), including Dissolved Organic Carbon (DOC) and Dissolved Organic Nitrogen (DON) is an important constituent of soil solution that plays an important role in many chemical and biological processes in forest ecosystems. DOC fluxes interact with biogeochemical N and P cycles, aid in pollutant transport, soil pedogenesis and may be a main energy source for microorganisms in the soil. DON represents a significant pool of soluble N in many soils and freshwaters. While the production and fate of inorganic N are well understood, our comprehension of the process prior to the production of NH4+ within the N cycles remains poor and also studies that include DON dynamics in addition to DOC are few. soil management practices such as N-fertilization affect DON and DON content in soil samples. Although the effect of increased Nitrogen to forest soils has been addressed, it is still not clear how or if it will alter DON and DOC. The main purpose of this research is to evaluate the effect of different kind of N-fertilizers on the concentration of DOC, DON and DIN of two alfisols which located in the north of Iran. In addition it was worthy of attention to monitor the variation of microbial activity and soil pH during the experiment. Since soils were differed in texture the effect of two different soil textures was also considered. An experiment was carried out using complete randomized design with factorial arrangements (Two soil samples (S1& S2), mainly different in texture, and four levels of N-fertilizers that are urea (N-U), ammonium nitrate (N-NA), ammonium sulfate (N-SA) and control (N0) with the same N content of 0.2 g kg-1 in six different times) with three replications. At each time the soil units were sacrificed for determining DOC, DON, DIN, pH in soil extracts and soil respiration measured at these times simultaneously. All treatments were incubated for 60 days at 27 oC and at the field capacity moisture. The results of this experiment showed that N fertilizers had not very significant effect on DOC and the effects of N-U and N-SA was similar in both soils. The concentration of DON significantly decreased in all N treatments than in the control in both soils as DIN content increased during the period of 60 days of incubation. According to DIN and soil respiration results it was concluded that mineralization of organic matter increased in both soils after N addition and probably for that reason the amounts of DON decreased. The results showed that the variation of DON in S1 (clay loam) was related to PH changes but there was not such relationship in S2 (sandy loam). The decreasing pattern of DOC during the time was to some extent similar in two soils but the variation of DON was different between soils.

Near infrared reflectance spectroscopy to predict soil texture, organic C, and potentially mineralizable N CARGÈLE NDUWAMUNGU1, NOURA ZIADI1, GAËTAN F. TREMBLAY1, LÉONETIENNE PARENT2 1

Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Boulevard, Quebec, QC, Canada, G1V 2J3. 2 Department of Soil and Agri-Food Engineering, Université Laval, Québec, QC, Canada G1K 7P4 [email protected] Keywords: NIRS, prediction, reference data, calibration statistics Several methods have been developed to evaluate soil characteristics and nutrient availability. Most methods are based on chemical extractions. Near Infrared Reflectance Spectroscopy (NIRS) is a costeffective, time-saving, non destructive, and environmentally friendly alternative technique (Foley et al. 1998; Dunn et al. 2002). The objective of this study was to evaluate the effect of the number of coadded scans per spectrum on the accuracy of NIRS prediction of soil texture, organic C (Corg), and potentially mineralizable N (Nmin). Soil samples (n = 150), collected on a 15 ha field near Montréal, Québec, Canada, in 2000, were air-dried, ground using Wiley mill fitted with a 2-mm screen, and stored until analysis. Reference data, on dry matter basis, ranged from 100 to 600 g clay kg-1, 160 to 420 g silt kg-1, 25 to 725 g sand kg-1, 10 to 40 g Corg kg-1, and 15 to 65 mg Nmin kg-1. In 2007, soil samples were scanned using a NIRS instrument (Foss NIRSystems, model 6500, Silver Spring, MD, USA) and a rectangular transport cup (volume ≈ 25 mL). Three NIRS treatments were evaluated: 16, 32, and 64 co-added scans per spectrum. Sample spectra with the highest relative significance were selected as calibration (n = 60), validation (n = 15), and prediction (n = 75) sets using the WinISI III (ver. 1.50e) software (Infrasoft International, LLC, Silver Spring, MD, USA). All spectra were submitted to the same mathematical transformation treatment. The accuracy of calibration equations was evaluated using 3 statistics (Malley et al. 2004) for prediction set: the coefficient of determination (R2), the ratio of performance deviation [RPD = standard deviation of the reference values / standard error of prediction (SEP) for the prediction set], and the ratio error range (RER = range in the reference values for the prediction set / SEP). Across the co-added scan treatments, NIRS calibration equations for clay and sand content, and Nmin concentration showed excellent (R2 > 0.95, RPD > 4, RER > 20) to very good (0.90 ≤ R2 ≤ 0.95, 3 ≤ RPD ≤ 4, and 15 ≤ RER ≤ 20) performances. The NIRS calibration equations for silt content were very good to good (0.80 ≤ R2 < 0.90, 2.25 ≤ RPD < 3, and 10 ≤ RER < 15). Clay and sand contents were more reliably estimated than silt content. The NIRS calibration equations for Corg concentration were good across co-added scan treatments. Hence, the number of co-added scans per spectrum had no significant effect on the accuracy of NIRS prediction of soil texture, Corg, and Nmin. Sixteen co-added scans per spectra appeared to be sufficient. Reference List Dunn, B. W., Beecher, H. G., Batten, G. D. and Ciavarella, S. 2002. The potential of near-infrared reflectance spectroscopy for soil analysis – a case study from the Riverine Plain of south–eastern Australia. Aust. J. Exp. Agr. 42: 607-614. Foley, W. J., McIlwee, A., Lawler, I., Aragones, L., Woolnough, A. P. and Berding, N. 1998. Ecological applications of near infrared reflectance spectroscopy – a tool for rapid, cost-effective prediction of the composition of plant and animal tissues and aspects of animal performance. Oecologia 116: 293-305. Malley, D. F., Martin, P. D. and Ben-Dor, E. 2004. Application in analysis of soils. Pages 729-784 in C.A. Roberts, J. Workman, Jr. and J.B. III Reeves eds. Near-infrared spectroscopy in agriculture. ASA, CSSA, SSSA, Madison, WI.

Does pH affect nitrate and sulphate sorption in Luvisolic soils? CRAIG NEUFELD*1, SCOTT X. CHANG1 1

University of Alberta, 4-37 Earth Sciences Building, Edmonton, Alberta T6G 2E3 [email protected]

Keywords: NO3- and SO42- adsorption, Luvisols, pH Processing of oilsands in the Fort McMurray area of Alberta has led to the emissions and subsequent deposition of large quantities of N and S compounds. Potential effects resulting from this deposition include the acidification of the soil (Aber et al. 1989) and the leaching of NO3- and SO42- (Park et al. 2003 and Prietzal et al. 2001). However, the leaching of NO3- and SO42- may be influenced by the decrease in pH of the soil, as would be caused by soil acidification. Bhatti et al. (1997) modeled the adsorption of SO42- in Brunisolic and Podzolic soils in northeastern Ontario over a range of pHs. A decrease in the pH increased the adsorption of SO42- in their model, corresponding to their observations. A decrease in the pH may therefore limit leaching of NO3- and SO42- in Luvisolic soils in Alberta by increasing the adsorption of those anions. The potential for pH to influence the adsorption of NO3- and SO42- in Luvisolic soils commonly found in the Ft McMurray area is unknown. We investigated the potential for pH to influence the adsorption of NO3- and SO42- in a Luvisolic soil using soils obtained from southeast of Fort McMurray Alberta, in a region with relatively little ambient N and S deposition. Batch equilibrium experiments were conducted at a pH of 3, 4, 5, and 6, and at varying concentrations of NO3- and SO42- in order to determine the effects of pH on adsorption. Reference List Aber, J.D., Nadelhoffer, K.J., Steudler, P., Melillo, J.M., 1989. Nitrogen Saturation in Northern Forest Ecosystems. Bioscience 39: 378-386. Bhatti, J.S., Foster, N.W. and Evans, L.J. 1997. Sulphate sorption in relation to properties of podzolic and brunisolic soils in northeastern Ontario. Canadian Journal of Soil Science 77: 397-404. Park, J.H., Mitchell, M.J., McHale, P.J., Christopher, S.F. and Myers, T.P. 2003. Impacts of changing climate and atmospheric deposition on N and S drainage losses from a forested watershed of the Adirondack Mountains, New York State. Global Change Biology 9: 1602-1619. Prietzal, J., Weick, C., Korintenberg, J., Seybold, G., Thumerer, T. and Treml, B. 2001. Effects of repeated (NH4)2SO4 application on sulphur pools in soil, soil microbial biomass, and ground vegetation of two watersheds in the Black Forest/Germany. Plant and Soil

N balance with respect to N management practices by using 15N JUDITH NYIRANEZA*1, MARTIN H. CHANTIGNY2, ADRIEN N’DAYEGAMIYE3, AND MARC R. LAVERDIÈRE3 1. Université Laval. Pavillon Paul Comtois. Québec, QC, Canada. G1K 7P4. Tél. 418-644-6702 2. Agriculture et Agroalimentaire Canada. 2560 Boul. Hochelaga. Québec, QC, Canada. G1V 2J3. 3. Institut de Recherche et de Développement en Agroenvironnement (IRDA). 2700, Rue Einstein. Québec, QC, Canada. G1P 3W8. [email protected] Keywords: corn, barley, nitrogen response, 15N, nitrogen recovery The availability of soil N is variable and is influenced by cropping practices. However, the relationships between management of N and its availability are still poorly understood. This study was conducted on two adjacent long-term field trials established on a same soil since 1977. The experimental treatments consisted of mineral fertilization (NPK) and NPK + manure in a corn (Zea Mays L.) –corn- barley (Hordeum vulgaris L.) rotation (NPK–CB and NPKM–CB), and NPK + manure in a corn – prairie rotation (NPKM–CP). Labeled (3.1 atom% 15N) mineral N fertilizer was applied on micro-plots to the corn phase of rotations in 2005, and on a new set of micro-plots to the barley phase of rotation in 2007. Crop yield, N uptake, N derived from fertilizer (Ndff), and 15N balance in the soil-plant system were evaluated at crop harvest. The 15N distribution was assessed in soil aggregate size-classes and in particulate organic matter. In all cases, corn and barley yield and N uptake decreased in the following order: NPKM–CP > NPKM–CB > NPK–CB. The soil N contributed 62 to 163 kg N ha-1 to corn, and 30 to 43 kg N ha-1 to barley. The highest values for corn were recorded in the NPKM–CP treatment. The portion of 15N fertilizer recovered by corn ranged from 40 to 59%, and from 44 to 50% for barley, with the lowest recoveries found in NPKM–CP. Twenty five to 45% of the applied 15N was recovered in the soil (020cm) at corn harvest, compared to 20 to 29% at barley harvest, with the highest recoveries observed in the NPKM–CP. In all, 86 to 99% of the applied 15N was recovered in the soil – plant system when corn was grown, compared to 70 to 82% when barley was grown. Under corn, the residual effect in the second and third year after 15N application was low with crop N recovery ranging from 0.29 to 2.3%. Even though not significant, the Ndff in POM and macro-aggregates size consistently followed the following trend: NPK-CB > NPKM-CB > NPKM-CP.

The present study showed that soil N contributed a significant portion of total corn and barley N uptake, especially in the manured soils.

Influence of cover crops on nitrogen cycling in a pea-cover crop-sweet corn rotation KELSEY A. O’REILLY*1, LAURA L. VAN EERD1 1

Department of Land Resource Science. University of Guelph Ridgetown Campus; Ridgetown, ON N0P 2C0 [email protected] Keywords: cover crops, nitrogen, oilseed radish, rye, oats Ontario vegetable growers are concerned that changes in N dynamics due to cover crops may or may not be beneficial to the subsequent vegetable crop. Information regarding N credits of cover crops in horticultural systems needs to be assessed to improve N best management practices. A field experiment was established in 2006 in a pea (Pisum sativa L.) - cover crop - sweet corn (Zea mays L.) rotation near the University of Guelph Ridgetown Campus. The objectives were to study the effect of various cover crops on N cycling and dynamics in the aforementioned rotation in order to assess the potential to minimize N leaching and determine if cover crops contribute an N credit to the following crop. The four cover crop treatments were i) no cover control, ii) oats (Avena sativa L.), iii) fall rye (Secale cereale L.), and iv) oilseed radish (Raphanus sativus L. var. oleoferus Metzg Stokes) plus rye (OSR+rye) seeded with a drill at 80, 67, 9+34 kg ha-1, respectively. Nitrogen treatments in the sweet corn crop were 0 and 140 kg N ha-1 of ammonium nitrate applied pre-plant. Cover crop biomass and N content as well as soil mineral N (NO3--N and NH4+-N) at 0-30, 30-60 and 60-90 cm depths was quantified early September, mid-October, mid-December and twice in May the following year. Additional crop and soil samples were collected five times during the sweet corn growing season. Marketable and total sweet corn yields were determined. All cover crops established well. Based on % N content and biomass accumulation, 2½ months after cover crop planting, N uptake in the above ground tissue was approximately 30 kg N ha-1 and was not different between the three cover crops. By mid-December, the oats had accumulated more approximately 80 kg N ha-1 more than rye, due to higher biomass production. The following spring, approximately 50 kg N ha-1 was in the cover crop residue. Thus cover crops following peas accumulate significant quantity of N. One month after cover crop planting there was no difference in soil mineral N between treatments. By mid-October, soil mineral N was 45% lower in all cover crop treatments compared to the no cover control. However by mid-December, soil mineral N in the no cover and OSR+rye treatments were not different from each other and were higher than the two cereal cover crops. At this time, both oats and OSR had senesced. Rapid mineralization of OSR due to a high C:N ratio compared to oats provides explanation to the increase in soil mineral N in the OSR+rye treatment compared to the other cover crops. This result suggests that cover crops may delay, not prevent, N losses. In the following spring, rye had higher N content than all other treatments and lower soil NO3--N in the top 30 cm than the no cover control. Cover crop treatment had no effect on either marketable or total sweet corn yield. As expected, marketable and total sweet corn yields were higher in the fertilized than no N fertilizer treatment at 6.8 and 10.5 t ha-1, respectively. In the non-fertilized sweet corn treatment, soil NO3--N in the top 30 cm over the entire growing season was significantly lower in rye than the no cover control treatment. This was not observed in the fertilized treatment. Therefore, in the fertilized sweet corn crop, there appeared to be no N credit or penalty to planting the cover crops tested.

Nitrogen dynamics in a Prairie landscape: comparing measures of soil mineral N content and gross N cycling rates MAXIME PARÉ*1, ANGELA BEDARD-HAUGHN1 1

Department of Soil Science, 51 Campus Drive, Saskatoon, SK [email protected]

Keywords: nitrogen, mineralization, grassland There is relatively little information on what proportion of organic N is taken up directly by plants compared to that which is converted into inorganic forms, albeit as part of a tightly coupled N cycle, prior to plant uptake. Some researchers in conservative N ecosystems (boreal forest, Arctic) are currently extracting mineral N in soil using Plant Root Simulator (PRS) probe-ion exchange membranes (Western Ag Innovation, Inc., Saskatoon, Canada) as a measure of N availability. We wanted to determine whether there is a significant correlation between these measures of N availability: gross mineralization/nitrification, soil mineral N content using soil KCl extractions, and mineral N availability from PRS probes. This could potentially facilitate future efforts to scale-up research findings. Twelve sampling locations per land management (cultivated and grassed) were selected on either shoulders (6 points) or depressions (6 points) at the St. Denis National Wildlife Area, Saskatchewan. On each point, PRS probes were incubated for 2 weeks (June 28th to July 12th 2007). Gross N mineralization and nitrification were measured during this period using 15N pool dilution technique. Mineral N in soil was extracted with 2 m KCl during pool dilution technique measurement and analyzed by colorimetry. Land management, topographical position, PRS© probes N values (NH4+ and NO3-), soil N contents, mineralization and nitrification interactions were analyzed using the General Linear Model statistical procedures. The results suggested that soil N nitrification/consumption and NH4+ consumption were not correlated with any variable. For the grassland management only, the gross N mineralization was significantly but weakly correlated with the topographical positions (R2=0.563). Although the repetition number was not enough high to extrapolate too far the discussion, these results suggested that the PRS probes are not able to estimate the gross N rates (i.e., mineralization/nitrification and NH4+/NO3consumptions) for both land managements. Implications of these results will be discussed.

Time series analysis of impacts of tillage on soil temperature GARY PARKIN AND PETER VON BERTOLDI Land Resource Science, University of Guelph. [email protected] Keywords: tillage, soil temperature, time series analysis The method of tillage can affect many soil biophysical properties including the temperature of the soil. Soil temperature differences between fall ploughed (FP) and no tillage (NT) systems may impact crop yield, for example. In this study we use conventional time series analysis (autocorrelation and spectral power) to investigate differences in soil temperature between FP and NT systems. As well, state-space analysis and an analytical solution for soil temperature estimation are compared as approaches to use for assigning missing data. Soil temperature data were collected at Elora Research Station from January 2001 – December 2007 under both FP and NT systems. Measurements were taken hourly using Campbell Scientific thermistors connected to a 23X datalogger. Temperatures were measured at 5, 25, 55, and 85-cm depths in 2 plots for each treatment. Data were analyzed using MATLAB, Mathcad, and R software packages. Results will demonstrate any differences in soil temperature that have developed since the NT was initiated in 1999. As well, recommendations on the best approach to assign missing data will be given.

Pulpmill biosolids and urea affects soil N cycling and N2O Emissions in a hybrid poplar plantation in northern Alberta SARAH R. PATTISON*1, SCOTT X. CHANG1, BARB R. THOMAS1,2 1

Dept. of Renewable Resources, 4-42 Earth Science Building, University of Alberta, Edmonton, Alberta, T6G 2E3 2 Alberta-Pacific Forest Industries Inc., Box 8000, Boyle, Alberta, T0A 0M0 [email protected] Keywords: Pulpmill biosolids, urea, nitrous oxide, hybrid poplar, nitrogen supply rates Hybrid poplar plantations are typically developed to increase the production of industrial sources of wood fiber. Fertilizers are often applied to increase the growth rates of plantation trees. Pulpmill biosolids, a waste product from the Alberta-Pacific Forest Industries Inc. (Al-Pac) pulpmill, can be land spread as a fertilizer amendment as a way of managing this waste by-product. However, the application of fertilizers and pulpmill biosolids can lead to increased emissions of greenhouse gases from the soil due to the additional nutrients made available to the soil microbial communities. We studied the effects of pulpmill biosolids and urea applications on soil N cycling and N2O emissions in a hybrid poplar plantation located near the Al-Pac pulpmill, approximately 50 km northeast of Athabasca, Alberta. Measurements were made in a six-year-old hybrid poplar plantation during the 2007 growing season on 16 plots, 21 m by 21 m, following the application of: 1) urea (200 kg N/ha) and triple-superphosphate (TSP) fertilizer (50 kg P/ha), 2) pulpmill biosolids (40 dry tons/ha), 3) a combination of both amendments, and 4) untreated control plots. Gas samples were collected using 0.1 m2 static gas chambers on trough and berm positions (two per position for a total of four per plot). These positions were formed during plantation establishment and maintained through regular cultivation. Sampling intensity varied from biweekly prior to fertilization, two times per week for five weeks after fertilization, and then weekly until November. The gas samples were analyzed using a Varian CP-3800 GC. Plant Root Simulator (PRS)TM probes were used for measuring potential nitrogen (NH4+ and NO3-) supply rates in the top 10 cm of the soil profile, for berm and trough positions, for three thirty-day burial periods (burial periods between June and September). The rate of N2O emissions was significantly greater for inorganic fertilizer and combination treatments for five weeks after fertilization; the rates were approximately four times greater than those recorded in the control plots. The urea + TSP treatment had the highest potential supply rate for nitrate for both trough and berm positions (265.35 and 224.85 µgN/10 cm2/month, respectively), while the biosolids treatment had the lowest for both trough and berm (8.88 and 11.61 µgN/10 cm2/month, respectively). The higher nitrogen availability in the urea + TSP treatment allowed more mineralization, and there was a greater potential of immobilization occurring in the biosolids treatment due to the high C:N ratio (32.0) of the biosolids. Ammonium supply rates were not different between treatments or positions; however they were significantly changed with time. This may be explained with changes in soil temperature over the season. Better understanding of the impact of various fertilizer amendments on soil nitrogen availability and greenhouse gas emissions from hybrid poplar plantations, will improve our silvicultural management practices for reducing C and N emissions to the atmosphere and quantifying its contribution to tree growth.

Mineral transformations in clay liners subjected to hyperacidic conditions: a Si and Al XANES spectroscopic study DEREK PEAK1, SEAN SHAW2, JIM HENDRY2 1

Department of Soil Science, University of Saskatchewan; Department of Geological Sciences, University of Saskatchewan; [email protected]

2

Keywords: mineral dissolution, XAS, mineralogy, environmental chemistry Natural and constructed clay liners are routinely used to contain waste and wastewater. Although widely investigated in relation to acid mine drainage systems at pH > 1.0, we know little about the impact of sulphuric acid (H2SO4) on the geochemistry and mineralogy of clays at pH < 1.0 (including negative pH values). This is a relevant research question for western Canada's Oil Sands production, as large blocks of zero-valent sulphur are commonly stored on clay liners and leachate can routinely be present at pH < 1.0. To understand the mineral transformations that occur when clay liner materials are subjected to sulphuric acid solutions, aluminum (Al) and silicon (Si) K-edge total electron yield, fluorescence yield (FY), and L-edge FY X-ray absorption near edge spectroscopy (XANES) analyses were conducted. XANES analysis was performed on a variety of Si and Al mineral standards as well as three different clay liner materials to investigate the impact of H2SO4 on the short-range coordination of Al and Si between pH 1.0 to -3.0 over 14 to 365 day reaction times. Acidic dissolution of clays resulted in the measurable alteration of the short-range Al and Si order from aluminosilicate coordination. We could confirm the dissolution of aluminosilicate Al-octahedral layers at pH < 1.0 and t > 14 d. Moreover, four-fold coordinated Al persists relative to six-fold coordinated Al under increasingly acidic conditions, and a new phase consistent with Al2SO4 was observed. The Si XANES results also demonstrated the dissolution of Si-tetrahedral layers and subsequent precipitation of a higher ordered tectosilicate Si coordination at pH < 0.0 and t > 90 d. An overall description of how mineral dissolution and reprecipitation occurs in clay liners subjected to hyperacidic conditions was then developed.

Selenium oxyanion adsorption at the metal oxide/water interface: A Se Kedge XAS spectroscopic study DEREK PEAK1 1

Department of Soil Science, University of Saskatchewan [email protected]

Keywords: mineral dissolution, XAS, mineralogy, environmental chemistry Sorption processes at the mineral/water interface typically control the mobility and bioaccessibility of many inorganic contaminants, including selenium oxyanions. Selenium is an important micronutrient for human and animal health, but at elevated concentrations selenium toxicity is a concern. The objective of this study was to determine the bonding mechanisms of selenate (SeO42-) and selenite (SeO32-) on a variety of iron and aluminum oxide surfaces over a wide range of reaction pH using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy.

This presentation will compare and contrast selenate and selenite bonding mechanisms on aluminum and iron oxides with Me2O3, MeOOH, and Me(OH)3 structures. From these studies, we will support the overall conclusion that the surface structure of metal oxide minerals has a rather dramatic effect on bonding mechanisms of oxyanions for these systems.

Hydrological triggers for CH4 and N2O emission events from Prairie wetlands DAN PENNOCK1, TOM YATES1, KIM PHIPPS1, RICHARD FARRELL1, BING SI, and ANGELA BEDARD-HAUGHN1 1

Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 [email protected] Keywords: greenhouse gases, wetlands The defining feature of the Prairie Pothole Region is the countless wetlands embedded in agricultural landscapes and no accounting of greenhouse gas emissions from these landscapes can be complete without assessing their contribution. Emissions from wetlands and surrounding agricultural catchments were made over four years at the St. Denis National Wildlife Area 40 km east of Saskatoon SK. Emissions of both gases from a large semi-permanent pond at the site were relatively low in all four years of the study. Interannual differences in emissions of CH4 and N2O were greatest from the basin centers of the ephemeral ponds in the agricultural landscape. The major triggering event for emissions of both gases from the basin centers of these ponds was drainage of water from the pond surface and a rapid decrease in water-filled pore space from 80-90% to less than 60%. High emissions of CH4 were also associated with a 100 mm precipitation event that occurred on June 17 and 18th 2005. Modeling of greenhouse gas emissions from wetlands in these landscapes will require integration of hydrological processes that control pond flooding and drainage with biogeochemical models of the greenhouse gas emission processes.

The water is moving the wrong way: Prairie hydrology and discharge soils DAN PENNOCK1 1

Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 [email protected] Keywords: wetlands, salinity, hydrology The dominant model to explain water movement in hummocky terrain in the Prairie Pothole region has undergone a substantial revision in the past decade. Studies on the direction and magnitude of water flow in these landscapes have demonstrated that the contribution of depression-focused deep drainage to groundwater is limited and that instead the dominant direction of water flow is lateral from the wetland to the surrounding wetland fringe. Rather than groundwater discharge, the source of the pond water in many wetlands is now understood to be from spillover of other wetlands during episodic fill-and-spill events, and the solute content of these ponds is largely controlled by their position in the spillover sequence and the long-term retention of salts in the underlying pond sediments. As the laterally moving water is evapo-transpired from the wetland fringe, the solutes are precipitated out in the surrounding soils. For these discharge soils the dominant direction of water flow is vertically towards the surface, rather than from the surface to depth in the soil; the balance between the two directions will change over time in response to climatically driven changes in site hydrology during the Holocene. The resulting soils typically have A and B horizons enriched in secondary carbonates or more soluble salts (depending on the chemistry of the pond water) and often formation of the typical indicators of reducing conditions (e.g. reduced matrix or iron mottling) is suppressed by the high pH conditions. Soils with an Ahca/Bmca/Cca sequence are common, yet this is a horizon sequence that fits very uncomfortably in the Canadian System of Soil Classification and indeed even the use of the ca suffix with A and B horizons is problematic. These are a widespread class of wetland soils that require a more coherent place and nomenclature within the Canadian System of Soil Classification.

Automated ecological mapping - what is it and how does it work? TANIA E. PERZOFF1, ROBERT A. MACMILLAN2 1

EBA Engineering Consultants Ltd., Oceanic Plaza, 9th Floor, 1066 West Hastings Street, Vancouver, BC, V6E 3X2 [email protected] 2 LandMapper Environmental Solutions Inc. 7415 118 A Street NW, Edmonton, Alberta, T6G 1V4 Keywords: predictive, mapping, ecological, automated Automated ecological mapping (or predictive mapping) uses computer, Geographic Information Systems (GIS), and knowledge-based methods to stratify landscapes into ecologically meaningful map units. Map units are based on the overlaying of existing mapped data and the processing of resulting attributes by automated inferencing software that use formalized knowledge bases that identify ecological-landscape relationships (Resources Inventory Committee 1999). Predictive mapping relies on a few, simple protocols, which include: (1) deciding what to map; (2) obtaining (appropriate) input data; (3) developing predictive equations or rules; (4) applying the equations or rules; (5) evaluating the predictive accuracy; and (6) producing final maps. These protocols can work for soils mapping (and by extension soil carbon) as much as they have been shown to work for ecosystem prediction. Virtually all digital mapping share common traits. The approach for predicting entities (i.e., ecosystems or soils) assumes that a predictive relationship exists between input environmental attributes and the output classes or properties to be predicted. Emphasis is placed upon the importance of landform, and assumes that a process-form or cause-effect relationship exists between landforms and soils or ecosystems. Many predictor variables are derived from Digital Elevation Models (DEMs). Modelling soil carbon using a digital mapping approach would be similar to that used to map other entities such as ecosystems; the approach rests with the identification of appropriate relationships and linkages. What to map or predict (in this case, soil carbon), what predictor variables will be used (e.g., soil types, vegetation types, landforms), and what methods will be used to develop and apply rules or equations (e.g., fuzzy logic, rule sets) could all be formulated in a similar manner. Information such as that provided by the Canadian Soil Organic Carbon Database (Tarnocai and Lacelle 1996) and the Soil Landscapes of Canada (Shields et al. 1991) can also be incorporated into map development, as appropriate. Reference List Resources Inventory Committee (RIC). 1999. Standard for Predictive Ecosystem Mapping. Inventory Standard. Version 1.0. Province of British Columbia. Tarnocai, C. and B. Lacelle. 1996. Soil Organic Carbon Digital Database of Canada (Revised 1999). Eastern Cereal and Oilseed Research Centre, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Canada. Shields, J.A., C. Tarnocai, K.W.G. Valentine, and K.B. MacDonald. 1991. Soil Landscapes of Canada. Procedures Manual and User’s Handbook.

Effects of broadleaved tree species on nutrient cycling and carbon sequestration in forest floors: myths, surprises, and a solution CINDY E. PRESCOTT Faculty of Forestry University of British Columbia 2005-2424 Main Mall Vancouver, BC, Canada V6T 1Z4 [email protected] Keywords: nitrogen, litter, decomposition, mineralization, soil fauna Broadleaved tree species, in comparison to conifers, are believed to have higher-quality litter which, both directly and by stimulating activities of soil fauna, cause to it decay faster. This, in turn, leads to higher availability of nitrogen (including nitrate) and smaller accumulations of organic matter (hence carbon sequestration) under broadleaf species. Results from a number of field and laboratory experiments have not been consistent with some of these assumptions. Although many broadleaves have higher litter quality (higher N and Ca; less recalcitrant components) than most conifers, differences in decay rates are small and temporary, and organic matter accumulation and C sequestration are usually not lower under broadleaves. Ammonium and nitrate availability are often higher under broadleaves, but this can be attributed to higher N and Ca contents of litter rather than faster decomposition and mineralization of N. A new hypothesis is proposed to explain differences in the characteristics of broadleaf and conifer forest floors.

Assessing suitability of woody wastes and co-composts for rehabilitation of forest roads and landings in British Columbia CAROLINE M. PRESTON1, CINDY E. PRESCOTT2, KIRSTY H. VENNER2 1Pacific Forestry Centre, Natural Resources Canada, 506 West Burnside Road, Victoria BC V8Z 1M5 2Faculty of Forestry, University of British Columbia, Vancouver BC V6T 1Z4 [email protected] Keywords: 13C CPMAS NMR, phenolics, condensed tannins, wood waste, leaching Rehabilitation and reforestation of disused forest roads and landings can be facilitated by incorporation of organic matter. The British Columbia forest industry creates residual woody materials, but they are nutrient-poor and there is concern that they may leach phenolic compounds after application. We assessed the potential for wood wastes (chipped cedar wood waste, sort-yard waste, hogfuel) and co-composts with shellfish waste or municipal biosolids to provide inorganic N and release phenolics and condensed tannins, compared with natural forest floor and mineral soil. This laboratory study was undertaken to complement field studies established to monitor soil and vegetation responses to woody waste amendment of forest roads and landings. The wastes and corresponding natural soils were collected for establishment of the field trials at coastal (near Tofino, Vancouver Island) and interior (near Okanagan Falls) sites. Initial concentrations of tannins and phenolics were low, and 13C nuclear magnetic resonance (NMR) spectroscopy with cross-polarization and magic-angle spinning (CPMAS) showed that composts were still dominated by wood. During a 426-day laboratory leaching experiment, release of phenolics from woody amendments (other than cedar wood) was lower than from native forest floor. The pH of woody amendments and their leachates were also within the range of native forest floor and soil (except cedar wood which was the most acidic material). Co-composts had higher total N and available P, greatly reduced tannins and phenolics, and negligible leaching of polyphenols. Uncomposted materials released very little N during the incubation. Hogfuel-biosolids compost released a large amount of nitrate, but only during the first 100 days. Shrimp-wood compost released moderate amounts of both ammonium and nitrate throughout the incubation, had high available P and low tannin content and released less polyphenols than did native forest floors. Our results support use of these amendments to facilitate soil rehabilitation and forest re-establishment on disturbed sites, with low environmental risk under appropriate conditions (Venner et al. 2008). Venner, K.H., Prescott, C.E. and Preston, CM. 2008. Leaching of nitrogen and phenolics from wood waste and co-composts used for road rehabilitation. J. Environ. Qual., in press April/08.

How important is black (pyrogenic) C to the C cycle in Canadian forest soils? C.M. PRESTON Pacific Forestry Centre, Natural Resources Canada, 506 W. Burnside Rd., Victoria BC V8Z 1M5 [email protected] Keywords: carbon cycle, boreal forest, black carbon, fire Despite the high current interest in black carbon (BC) as a stable component of soil C, it has so far hardly been integrated into C cycle modeling, especially for forests. We refer to the whole range of fire-transformed biomass and soil organic matter as pyrogenic C (PyC), reserving BC and charcoal for specific stages along the “BC continuum” from lightly charred biomass to soot and graphite. Fire is the major disturbance in boreal forests, with production estimated at 7-17 Tg BC/y as solid residues (around 1-3% of original mass) and 2-2.5 Tg BC/y as aerosols (Preston and Schmidt 2006). However, there is scant and scattered information on production, stocks, or loss rates, exacerbated by differences used to measure various forms of PyC. Incorporation of efficiently-produced “biochar” into agricultural soil is being considered to enhance both fertility and C sequestration. However, the stocks and sequestration potential of PyC in forest ecosystems may be limited, due to several factors. Compared to production charcoal, wildfire-produced PyC is generally less highly transformed, but higher in N, other nutrients, and oxygen-bearing functional groups. This and its high porosity make it less resistant to physical, chemical and microbial degradation. It is produced, and largely remains above, on, or just below the surface. Charred snags may remain standing or suspended for many years. While this prevents soil contact, the PyC is still vulnerable to physical and chemical processes, including possible effects of photochemical oxidation followed by leaching of water-soluble fragments. PyC on or in surface horizons is also vulnerable to oxidation by subsequent fires, which may be the main constraint on its sink potential. We are exploring research requirements and approaches for establishing the role of PyC in boreal forest soils, and also for its integration into the Carbon Budget Model of the Canadian Forest Sector 3 (CBM-CFS-3). Preston, C.M., Schmidt, M.W.I. 2006. Black (pyrogenic) carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions. Biogeosciences 3: 397-420. (open access at: http://www.copernicus.org/EGU/bg/bg/recent_papers.html)

Lignin, black boxes and SOM mythbusting CAROLINE M. PRESTON1, J.A. (TONY) TROFYMOW1 1

Pacific Forestry Centre, Natural Resources Canada, 506 W. Burnside Rd., Victoria BC V8Z 1M5 [email protected]

Keywords: decomposition, CIDET, proximate analysis, lignin, ecological myth Advances in soil ecology continue to be further decoupled from advances in soil organic matter (SOM) chemistry. Decomposing litter or SOM is often described as a “black box” of unimaginable complexity, or else limited to its composition from sequential proximate analysis (non-polar and polar extractives, acid-hydrolyzables, acid-unhydrolyzable residue (AUR). However, it has been possible for decades to account for high proportions of litter and poorly-decomposed SOM as single compounds (e.g., sugars, amino acids, cutin and lignin monomers). While the yields of recognizable structures generally decrease with decomposition and mineral interaction, they are non-negligible, and it is time to retire the “black box” cliché, which is largely an excuse for avoiding the issue. Second, for most low-tannin woods, the yield of AUR (originally called “Klason lignin”) closely corresponds with their content of lignin, a complex 3-dimensional phenylpropane-based polymer produced only by higher plants. However, it has been now known for approximately 1/4 century that lignin is a minor component of most foliar litters which can also have substantial proportions of tannins and cutins. Both of these (or suberin in roots and bark) contribute to the AUR. Third, AUR or AUR/N is a robust indicator of relative resistance to decomposition, and because of its “lignin” misnomer, widespread in ecological and modelling literature, the leap has been made that “lignin” is resistant and the primary controller of decomposition. However, this well-entrenched myth is becoming a stranglehold on innovative approaches to decomposition research. For example, the commonly-observed negative influence of N on decomposition is largely considered only with respect to inhibition of lignindecomposing enzymes of white-rot fungi, although resistance is more likely due to a combination of other factors. These include: high proportions of other structures at least as recalcitrant as lignin – suberin, cutin, plant waxes, tannins, crystalline cellulose; physical interactions such as tannin-protein complexes and hydrophobic interactions; covalent bonds causing cross-linking; increasing concentrations of heavier elements that increase chemical stability, and are in themselves toxic. This gulf between geochemical and ecological approaches is usually dismissed as “it doesn’t matter” and “I can’t afford NMR… or whatever in my lab”, but in addition to the stranglehold on scientific progress, also has serious ethical considerations. Is it right to deny students well-established knowledge about litter and SOM structure – much of which was already known before most of them were born? Is it right to feed them myths upon which to base erroneous hypotheses and maybe their whole careers? Do not scientists, funding agencies, and journals have some collective responsibility to truth and good science, even if this means engaging in extra-tribal collaborations? Would we stick with a working hypothesis that the world is flat, because we personally are not going to sail around the world to check it out? Would it be appropriate to call all ungulates, cows or all white-rot-fungi, Mycena sp., “for convenience”? The main limitations to dealing with the substrate side of soil ecology are presently tribal and cultural not technical, or even monetary, although this is often used as the excuse, and blame is certainly not all on the ecologists’ side. Much more collaboration and less reliance on rote hypotheses can allow plants, litter and SOM to tell their own wonderous and complex stories, which in turn can only facilitate further advances in soil ecology.

Changes in dissolved organic carbon from a peatland under experimentally altered hydrological regimes MICHAEL PRESTON*1, SHAUN A. WATMOUGH2, M. CATHERINE EIMERS3 1

Watershed Ecosystem Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8 2 Environmental and Resources Studies Department, Trent University, Peterborough 3 Department of Geography, Trent University, Peterborough [email protected] Keywords: DOC, Decomposition, Peatlands, Climate change Peatlands are large repositories for atmospheric carbon, and are also important sources of dissolved organic carbon (DOC) export to downstream surface waters. Climate model projections for changes in precipitation quantity and quality could have serious implications for wetland hydrology and DOC export, by altering water table height and thus DOC production. In order to investigate the potential impact of changes in water table height in peatlands, a peat microcosm study was established using peat collected from a coniferous swamp at a lake catchment in south-central Ontario. Two scenarios have been tested: drought and waterlogged conditions. In both experiments, a variety of chemical and biological parameters were measured to gain insight into the processes controlling DOC production, including the concentration of major ions, pH, microbial biomass and the activity of the extracellular enzyme β-glucosidase which is indicative of carbon mineralisation. Chemical structure of DOC was also measured in the two treatments, to further elucidate mechanisms controlling DOC production, and because changes in DOC structure may impact freshwater ecosystems by altering light transmission and the bioavailability of trace metals and organic contaminants.

Influence of annual papermill biosolid applications on field earthworm populations GORDON W. PRICE1, R. PAUL VORONEY2 1

Dept. of Engineering, Nova Scotia Agricultural College, Truro, NS, Canada B2N 5E3 Dept. of Land Resource Science, University of Guelph, Guelph, ON, Canada, N1G 2W1 [email protected]

2

Keywords: papermill biosolids, earthworm populations, organic amendments Papermill biosolids (PB) have been used as soil conditioners on agricultural soils, to reclaim mining soils, and to rehabilitate old landfill sites. Earthworm population responses to a de-inked PB were measured on three agricultural soils in southern Ontario, Canada. Four rates of PB, 0, 50, 100, and 150 Mg ha-1, were applied annually for three years. In addition, plots receiving the PB treatments were planted to corn (Zea mays L.) and soybean (Glycine max L.). Earthworm populations prior to PB applications ranged from 9 to 22 individuals m-2 on the sandy loam and loam soils. Linear increases in earthworm populations were observed ranging from approximately 153 to 280 individuals m-2 after 3 years of PB amendments. On the clay loam soil, initial fall earthworm populations were about 124 individuals m-2 which increased to 482 individuals m-2 after two years of PB applications. Earthworm population increases to PB amendments were evident after two to three years at the sites measured.

The transfer of prion-mediated animal diseases through soils and environmental pathways: a review GORDON W. PRICE1 1

Dept. of Engineering, Nova Scotia Agricultural College, Truro, NS, Canada B2N 5E3 [email protected]

Keywords: prions, transmissible spongiform encephalopathy, BSE, environmental pathways Controlling animal disease outbreaks requires an understanding of the pathogen transfer mechanisms in order to develop appropriate bio-security protocols. Diseases such as Scrapies, Chronic Wasting Disease, and Bovine Spongiform Encephalopathy (BSE) which are believed to be mediated by prions (derived from proteinaceous and infectious) have placed, in some cases, severe economic burdens on the livestock industry. Recent research is beginning to highlight the potential for soils to act as a reservoir for these infective proteins. Prions added to certain soils have been shown to remain highly infective for as much as 3 to 5 years. However, the mechanisms of transfer and the role of soils in degrading or protecting these proteins is still unclear.

Optimal soil physical quality: application of “S-Theory” W. DANIEL REYNOLDS1, CRAIG F. DRURY1, XUEMING YANG1, CHIN S. TAN1, CATHERINE A. FOX1 1

Agriculture & Agri-Food Canada, Harrow, Ontario, Canada N0R 1G0 [email protected] Keywords: soil physical quality, S-theory, desorption curve, pore volume distribution, indicators According to “S-Theory”, good soil physical quality (SPQ) is attained when the slope of the soil water desorption curve at the inflection point, S, exceeds a magnitude of 0.035 (Dexter 2004). Although the S criterion has been successfully correlated with soil strength, stability and workability indicators, there are few comparisons with the soil air-water storage indicators, such as relative field capacity (RFC), plant-available water capacity (PAWC) and air capacity (AC). In addition, there have been no attempts to develop “optimum” soil hydraulic properties using optimal SPQ indicator values. Hence, the objectives of this study were to: i) assess the S indicator relative to RFC, PAWC and AC for several agricultural soils and other porous materials with widely varying SPQ; and ii) use the calculated values and optimum ranges of S, RFC, PAWC and AC to propose for agricultural soils an “optimum” pore volume distribution function, and an “optimum” soil water desorption curve. Fifteen porous materials were examined including glass beads, “builders sand”, and 13 agricultural soils which ranged in texture from sand to clay. Land management on the soils included “virgin soil” (VS), and corn-soybean-winter wheat rotational cropping under no-tillage (NT) or moldboard plow tillage (MP). The S, RFC, PAWC and AC indicators were calculated using soil water desorption curves measured on intact or repacked soil cores; and the pore volume distribution functions were determined by plotting the slopes of the desorption curves against equivalent pore diameter (EPD). The RFC, PAWC and AC values were consistent for all 15 porous materials with respect to their indication of “optimal”, “aeration limited” or “water limited” SPQ conditions. For the clayey and loamy soils, the S parameter values were consistent with the RFC, PAWC and AC values, which indicated “optimal” or “aeration limited” SPQ. For the sandy soils, glass beads and builders sand, on the other hand, the S parameter suggested “very good” SPQ (i.e. S ≥ 0.05), whereas the other parameters indicated poor SPQ due to substantial water limitation. Poor SPQ due to water limitation was the expected result for these materials owing to their coarse, single-grain textures and low organic carbon contents. Four of the agricultural soils were judged to have optimal SPQ because of favorable values obtained from all four of the SPQ indicators. The normalized pore volume distribution functions from these soils were closely clustered and were therefore averaged to produce a proposed “optimal” pore volume distribution function and an “optimal” desorption curve (saturation basis) for agricultural soils. The inflection point of the optimal desorption curve occurred at about 76 % of saturation; and the optimal pore volume distribution was strongly left skewed (skewness = -0.42), mildly peaked (kurtosis = 1.13), and it produced modal, median and mean EPDs of about 100, 4 and 1 micron, respectively. It was concluded that S ≥ 0.035 can be a useful indicator of good SPQ from an air-water storage perspective for clayey and loamy soils, but not for sandy soils or other coarse, single-grain materials. The apparent existence of an optimum pore volume distribution function (normalized) and an optimum desorption curve (saturation basis) should assist in further characterization of desirable hydraulic properties for agricultural soils. References Cited Dexter, A.R. 2004. Soil physical quality. Part I: Theory, effects of soil texture, density and organic matter, and effects on root growth. Geoderma 120: 201-214.

Soil carbon sequestration in the boreal transition Saskatchewan: historical and current perspectives

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NAVID ROBERTSON*, BRADLEY D. PINNO, NICOLAS BÉLANGER Department of Soil Science, University of Saskatchewan, 51 Campus drive, Saskatoon, Saskatchewan, S7N 5A8 [email protected] Keywords: Chernozemic Ah horizons, charcoal, Holocene, tree farming, C dynamics The development of C-rich Chernozemic Ah horizons in the northern Great Plains is believed to come from the addition of organic matter through the roots of herbaceous vegetation and the limited degradation of this organic matter due to dry soils, thus forming stable humus compounds. However, these C-rich and Ca-saturated diagnostic soil horizons are often found under trembling aspen forests of the Boreal Transition ecoregion, suggesting that a transient vegetation cover between grasslands and forests has influenced the development of these soils during the Holocene. Recent research, including ours, shows that episodic burning of the forest has led to very significant charcoal incorporation into the Ah horizons, a significant long-term sink of C. In our study, charcoal pools were greater on richer sites (lacustrine deposits and glacial tills) where forests are thought to have been the dominant vegetation during the Holocene. The drier conditions of the fluvial sites have favoured the dominance of frequently burning grasslands. These conditions promoted the development of relatively thick Ah horizons but these sites had generally less charcoal than the others as herbaceous vegetation produces more ashes than charcoal when it burns. The Boreal Transition ecoregion where most of the Black and Dark Gray Chernozems occur are now being suggested as ideal for tree farming projects. Tree farming is being advanced as a means to provide an increased timber supply for mills, create another cropping option for agricultural producers and be part of the solution to meeting Canada’s carbon sequestration commitments. Despite the inherently high C pools in these Chernozemic soils, some suggest that tree farming will favour belowground C sequestration. We have data supporting that 50 years of growth of white spruce and Siberian larch planted on well-drained dark Chernozems (pasture) has favoured ecosystem C gains because of the standing wood biomass. However, C pools in the Ah horizons were decreased under trees and were redistributed to the B horizons. Multiple linear models indicate a significant shift from soil C being controlled by root litter quality in the Ah horizons to being controlled by root litter quantity in the B horizons. Our model of C redistribution therefore appears to be closely tied to root production and quality. Despite the clear role of trees and fire on long term C sequestration in these soils (i.e. charcoal production/incorporation), our data and previous research suggest that tree invasion on grassland/pasture/agricultural crop land leads to the devolution of well-drained dark Chernozems through acidification and C loss in the Ah horizon

Root-associated microbial communities differ with Pinus contorta and Vaccinium vitis-idaea co-inhabiting sub-boreal forest soils SUSAN J. ROBERTSON*1, P. MICHAEL RUTHERFORD2 AND HUGUES B. MASSICOTTE3 1

Natural Resources and Environmental Studies Program, 2Environmental Science and Engineering Program , and 3Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, Canada V2N 4Z9 [email protected] Keywords: mycorrhizas, shared rhizosphere, functional guild, petroleum hydrocarbons, LH-PCR Rhizosphere communities, including mycorrhizas and closely associated heterotrophic microorganisms, represent critical functional groups for decomposition and carbon/ nutrient cycling processes in northern forest ecosystems. The spatial heterogeneity of the soil environment contributes to the great biodiversity of soil microorganisms; however, the complexity of the system and the multifunctional nature of many microorganisms have made it difficult to comprehend linkages between communities and ecosystem processes and also to predict how ecosystems may respond to environmental disturbances such as soil contamination. In this study, we used a bioassay approach to assess the relative contributions of plant and soil properties to spatial distribution patterns of ecto(ECM) and ericoid (ERM) mycorrhizal fungi as well as root-associated bacterial communities inhabiting the shared rhizosphere of pine (ECM host) and lingonberry (ERM host); soil systems were either untreated or treated with petroleum hydrocarbons (PHCs), simulating contamination events. Surface-sterilized pine (Pinus contorta var latifolia) seeds and lingonberry (Vaccinium vitis-idaea) seedlings were planted into ConetainerTM pots containing an organic layer (mor humus [FH] or coarse woody debris [CWD]) overlying sandy mineral horizons (Ae and Bf) of field-collected forest soils obtained from central BC, Canada. After 4 months, BC light crude oil (219 mg cm-2) was applied to the soil surface around the seedling stem; systems were destructively sampled at 1 and 16 weeks following treatment. Soils from each layer were analyzed for PHC concentration (not presented here), pH and total C and N content. The composition, relative abundance and vertical distribution (ie. variation with soil layer) of eight frequently occurring ECMs on pine roots were assessed using light microscopy. Community profiles (i.e. based on the relative abundance of all genotypes) were generated for all root systems using length heterogeneity PCR and primers targeting the ITS (fungi) and 16S (bacteria) regions of ribosomal DNA. We found that the main components of ECM communities were consistent with those described from field-based studies. Genotype analysis by non-metric multidimensional scaling (NMS) and multi-response permutation procedures (MRPP) revealed that both plant and soil properties influenced the structure of root-associated fungal and bacterial communities; however, patterns of community structure varied among the different functional groups. Fungal communities were distinctly different on pine (ECM) and lingonberry (ERM) roots; only ECM fungal communities were structured vertically in the three layers of soil, representing direct interactions between fungi and soil in the ectomycorrhizal association. In contrast, ERM communities appeared to vary more between soil systems (i.e. FH-Ae-Bf and CWD-Ae-Bf) than between soil layers. Bacterial community structure varied between mycorrhizal root systems and between soil layers, indicating that differences between the ECM and ERM root environment and soil properties are both important with respect to bacterial niche differentiation. PHC contamination appeared to have little effect on the composition of root-associated microbial communities.

Riparian exclusion fencing for cattle impacts on suspended sediment in the Salmon River, southern interior B.C. BRUCE H. RODDAN, KLAAS BROERSMA Agriculture and Agri-Food Canada, 3015 Ord Rd. Kamloops B.C. V2B8A9 [email protected] Keywords: suspended sediment; exclusion fencing; cattle impacts; riparian Exclusion fencing is classed as a beneficial management practice (BMP) for controlling cattle grazing impacts on riparian soils, vegetation and water quality. Agriculture and Agri-Food Canada has studied the effectiveness of BMP fencing at the watershed scale at several locations across Canada since 2004 (WEBs study). From November 2004 to May 2006, an evaluation of riparian fencing was conducted within the property boundaries of three cow-calf pastures spread along a 10 km length of the Salmon River watershed in the Southern Interior of British Columbia, Canada. All three pastures had degraded riparian zones and eroded river banks. Cattle were fenced out of the river from the upstream half of each pasture and allowed access to the lower half. Fluvial suspended sediment (FSS) samples were collected from a point within the river cross-section using a time-integrated passive sediment sampler (TIPS) on a continuous basis. The TIPS samplers were deployed in the river for 2 week intervals at each of the pastures, at 3 sampling locations: the upstream and downstream boundary of the fenced treatment and the downstream boundary of un-fenced treatment. Throughout each year, measurements of FSS organic, mineral and bacterial components were taken to determine compositional differences between the fencing treatments. The results suggest that riparian exclusion fencing may have positively influenced water quality during times that cows were present within the three pastures between November 2004 and May 2006. Escherichia coliform was measured in greater numbers in the sediment collected from the un-fenced treatment compared to the fenced treatment. The TIPS samplers detected significant mean differences in collected sediment Escherichia coliform (0.53 colonies/ml of diluted re-suspended sediment, n=53, SD=1.77, p=0.033) between treatments. Reference List McDowell, R.W. and Wilcock, R.J. 2004. Particulate phosphorus transport within stream flow of an agricultural catchment. Journal of Environmental Quality 33: 2111-2121. Agriculture and Agri-Food Canada. 2008. Watershed evaluation of beneficial management practices (WEBs) Salmon River British Columbia. www.agr.gc.ca/webs 8pp. AAFC# 1031E.

Recreating a functioning forest soil in reclaimed oil sands in northern Alberta SARA M. ROWLAND*1, CINDY E. PRESCOTT1, SUSAN J. GRAYSTON1, SYLVIE QUIDEAU2, GARY BRADFIELD3 1

Department of Forest Sciences, University of British Columbia; 2424 Main Mall, Vancouver, BC, V6T 1Z4 2 Department of Renewable Resources, University of Alberta; 751 General Services Building, Edmonton, AB, T6G 2H1 3 Department of Botany, University of British Columbia; 3529-6270 University Blvd, Vancouver, B.C. V6T 1Z4, [email protected] Keywords: reclamation, nutrient, decomposition, PRS probes, ecotypes During oil-sands mining all vegetation cover, soil, overburden and oil-sand is removed, leaving pits several kilometres wide and hundreds of metres deep. These pits are reclaimed for commercial forestry by a variety of treatments using sub-soil or a mixed peat:mineral soil as the capping layer that may or may not be fertilised. Using non-metric multidimensional scaling and cluster analysis, reclamation treatments covering different age classes were compared with a range of natural forest ecotypes to discover which treatments were moving towards natural forest ecotype status and at what age this occurs. Ecosystem function was estimated from bio-available nutrients, plant community composition, litter decomposition rate and development of a surface organic layer. On reclaimed sites, bio-available nutrients including nitrate generally were outside the natural range of variability, while phosphorus, potassium and manganese were generally very low. Plant diversity was similar to natural sites but declined after 30 years with canopy closure. Peat:mineral mixtures generally retained more moisture than sub-soil caps, and created better conditions for decomposition but decomposition processes on reclamation treatments were depressed overall. Development of an organic layer appeared to be facilitated by the presence of shrubs. With repeated applications of fertilisers, peat:mineral amendments became similar to a target ecotype at about 20 years. An intermediate sub-soil layer reduced fertiliser dependency, and so long as this is not over tailings sand it achieved a target ecotype about 15 years after a single application. Treatments over tailings sand receiving only one application of fertiliser appeared to be on a different trajectory to a novel ecosystem.

Response of boreal forest carbon dynamics and storage to experimental drought (1989-2005) in interior Alaska SARAH A. RUNCK*1, DAVID W. VALENTINE1, JOHN A. YARIE1 1

Department of Forest Sciences, University of Alaska, PO Box 757200, Fairbanks, AK 99775-7200 [email protected] Keywords: drought, soil moisture, boreal forest, decomposition, carbon storage In interior Alaska, projected increases in potential evapotranspiration exceed those for precipitation, implying increased moisture stress in forests. Since 1989, we have erected “rain-out” shelters every May and removed them every September in order to induce summer drought in 10 x 15 m midsuccessional forested plots in upland (rock- and permafrost-free loessal Alfic Cryochrepts) and floodplain (rock- and permafrost-free Typic Cryofluvents) landscape positions (n=3). Treatment vs. control differences in near-surface soil moisture generally increased throughout each growing season as imposed summer drought (ISD) restricted soil moisture recharge from late-season rains. From 1989-2005, ISD slowed total aboveground biomass growth in upland sites but not in floodplain sites, where groundwater availability may have mitigated ISD. Although we observed slight or no difference in annual litterfall between treatments, ISD severely slowed decomposition of standard substrates (wooden tongue depressors) in the surface O horizon. Between 1989 and 2005, ISD caused O horizon C stocks to increase 15% faster in floodplain sites and 40% faster in upland sites relative to untreated controls. ISD had no effect on mineral soil C contents in floodplain sites, where buried O horizons comprise much of the subsurface C; in upland sites, ISD slowed mineral soil C accumulation. Taken together, these results suggest that future summer droughts are likely to reduce productivity, decomposition, and mineral soil C accumulation in upland forests but are unlikely to alter floodplain forest dynamics or soils in the absence of changes in groundwater availability.

Grassland soils in northwestern Canada: Chernozems (almost) north of 60? PAUL T. SANBORN1 1

Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 [email protected] Keywords: grassland, Chernozem, soil classification, micromorphology, soil temperature In the rain shadow of the Coast and St. Elias Mountains, grasslands occupy many south-facing slopes at low elevations in major valleys of northwestern British Columbia and southwestern Yukon. Although not extensive, these ecosystems provide locally important range resources. Botanically, these plant communities are noteworthy for their Beringian floristic affinities, and have been suggested as possible analogues for the full-glacial steppe-tundra inferred from the fossil record. Soils of these grasslands have been documented in southwestern Yukon at a limited range of sites influenced by Holocene deposition of loess and tephra. In northwestern British Columbia, only reconnaissance soil surveys have been conducted, and the characteristics and genesis of these grassland soils have not been investigated. A brief 2007 exploratory study of natural rangelands in the valleys of the Tuya and Stikine Rivers enabled an initial examination of soils in these grassland settings. Two pedons in the lower Tuya River valley, formed on complex colluvial and glaciolacustrine materials, show considerable affinities with Chernozemic soils documented in grasslands elsewhere in central and southern British Columbia. Ah horizons exhibit the spongy and granular microstructures typical of Chernozemic A horizons. Morphological and chemical criteria for the Chernozemic order appear to be met, but the scarcity of local climatic records makes it difficult to determine if these sites have the required soil temperature and soil moisture regimes. However, recent soil temperature research in central Yukon suggests that south-facing slopes at this latitude would easily satisfy the requirement for mean annual soil temperatures of 0ºC or higher.

Pedology and ephemeral environments: forest soils on Klutlan Glacier, Yukon Territory PAUL T. SANBORN1 1

Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 [email protected] Keywords: tephra, glaciers, refugia, soil genesis, Cryosols The ca. 1200 BP deposition of the White River tephra created a unique pedogenic environment in southwestern Yukon: supraglacial forest soils on the terminus of the Klutlan Glacier. Several meters of pumice gravel and finer tephra cover the stagnant toe of the glacier, and provide a parent material for Cryosols and Regosols that support a patchy forest dominated by white spruce (Picea glauca). Wasting of the underlying glacier ice has created a complex hummocky landscape with numerous thaw ponds that expand laterally, triggering slumping and repeated disturbance of the juvenile soils. Despite the instability of this substrate, forest floors have locally accumulated to > 15 cm in thickness, and an absence of charcoal suggests that fire is unusual in this setting. Morphologically, these soils have limited B horizon development, and their coarse texture has restricted the activity of cryoturbation. Cryptogamic crusts appear to be important in initial stabilization of exposed tephra surfaces created by slumping and erosion. Pedogenic modification of tephra may be accelerated by these crusts, as well as by root penetration into porous tephra particles. Although this pedogenic environment may be viewed as an ephemeral novelty, eastern Beringia has likely seen repeated interactions between glacial and volcanic activity during the Quaternary. Evidence of soil formation in these transient environments may not be preserved in the geological record, but since supraglacial vegetation occurs on other modern glaciers, such settings may have provided refugia on the margins of continental ice sheets. As such, these soils deserve further study as part of understanding ecosystem functioning through glacial-interglacial cycles.

Evaluating the N leaching potential for two different hydrological soil groups using a conservative tracer J.K. SASO1*, G.W. PARKIN1, J.D. LAUZON1, C.F. DRURY2 1

Department of Land Resource Science, University of Guelph, Guelph, Ontario Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, Harrow, Ontario [email protected] 2

Keywords: leaching, Ontario, N, conservative tracer Evaluating the Nitrogen (N) leaching potential of soils is important to agronomists, as they work to improve the efficiency of surface applied N fertilizers and reduce the amount of N moving beyond the root zone and into groundwater via tile drainage (Schoen et al., 1999). A field study is being conducted at the Elora Research Station, Elora, Ontario to evaluate the leaching potential of two soils with different hydraulic and textural properties. A conservative chloride tracer (applied as KCl) will be used as a surrogate to infer about the fate of NO3-N in the soil profile. In addition to the tracer, corn (Zea mays L.) will be used to evaluate plant N uptake from the residual N remaining in the soil compared to spring applied fertilizer N. Four instrumentation methods will be used to evaluate N movement and the use of Cl. Time Domain Reflectometry, a non-obtrusive, in-situ method to measure flux concentrations of Cl from the 0-43 cm depth; funnel lysimeters (at 30 cm depth) will evaluate solute movement via infiltrated water and solution samplers (similar design to Lord and Shepherd, 1993) will measure soil water concentrations of N and Cl at 60 cm depth. Soil coring, conducted when feasible, will evaluate resident concentrations of N and Cl at six different depths (up to 1 m). In addition to soil coring, plant samples will be taken throughout the growing season (May to August) to measure plant N uptake compared to residual N in the soil. Pending results will demonstrate if Cl is a good predictor of the leaching potential of a particular soil and can lead to more accurate quantification of N movement through the soil profile. Reference List Schoen, R., J.P. Gaudet, T. Bariac. 1999. Preferential flow and solute transport in a large lysimeter, under controlled boundary conditions. Journal of Hydrology 215:70-81 Lord E.I., Shepherd M.A .1993. Developments in the use of porous ceramic cups for measuring nitrate leaching. Journal of Soil Science 44:435-449

The occurrence and nature of a dominant coprogenous limnic layer in organic soils: challenges to the Canadian System of Soil Classification DANIEL SAURETTE1, LUC LAMONTAGNE2, ANDRÉ MARTIN2 1

Jacques Whitford AXYS Ltd., 103-611 Corydon Avenue, Winnipeg, MB, R3L 0P3 Agriculture and Agri-Food Canada, Pedology and Precision Agriculture Laboratories, 140-979 de Bourgogne Avenue, Quebec, QC, G1W 2L4 [email protected] 2

Keywords: organic soils, limnic materials, coprogeneous earth, soil classification, physical properties Organic soils cover approximately 10% (927,100 km2) of the Canadian land base, of which 60 % are found south of the permafrost line (Lévesque et al. 1981). In the Quebec Saint-Lawrence plain, deep organic soils (>1.6 m) occupy 145,000 ha and are of great local importance for supporting the peat production and agricultural sectors. In the South-Eastern area of the Montreal plain, 25,000 ha (Duguet 2005) of these organic soils play an important role in the local production of large harvests of root and leafy vegetables because of their climate regime and high fertility. It is called “The Quebec Garden”. Fibrisol, Mesisol and Humisol great groups are common in the region; however Mesisols and Humisols are dominant. A layer of limnic materials occurs frequently in these organic soil profiles and typically remains well below the surface. As a consequence of agricultural land drainage, an annual subsidence rate of 2.06 ± 0.35 cm/yr has been observed (Parent et al. 1982) and linked to increased wind and water erosion. The potential of exposing the limnic material layer at the surface is ever increasing. The typical limnic materials identified in these organic soils originate from sedimentary peat (coprogenous earth (Oco layer), also known as ‘gyttja’) which are a nutrient-rich peat composed of plankton, plant and animal residues (fecal matter) and mud. Morphologically, it is fine-textured, plastic and often gelatinous when wet. The gyttja soils pose challenges in two fields of soil science: soil classification and agronomy. Organic soils are classified based primarily on the dominant material present in the middle tier (40-120 cm) of the control section (0-160 cm). We have identified numerous organic soil profiles in which the middle tier is dominated, if not entirely composed of a limnic deposit. These soils are poorly captured by the current taxonomic criteria used in the Canadian System of Soil Classification (SCWG 1998) and present a strong case for modifications at the great group (i.e limnosols) or subgroup levels of the Organic Soil Order. From an agronomic perspective, little is known about the effects of coprogenous materials of this type on agriculture. Although it is high in nutrients, gyttja has been found to have physical properties which could make soils unsuitable for agriculture, either as a component ploughed into the organic soil at the surface or directly exposed. For example, when air-dried, it shrinks greatly, becomes hard and lumpy and is relatively inert. The overall philosophy of the Canadian system is pragmatic and the aim is to organize the knowledge of soils in a usable way based on properties of the soil. The CSSC should continue to evolve to better recognize these soils. Reference List Duguet, F. 2005. Minéralisation de l’azote et du phosphore dans les sols organiques cultivés du sudouest du Québec. M. Sc. Thesis, Laval University. 95pp. Soil Classidfication Working Group. 1998. The Canadian System of Soil Classification. Agriculture and Agri_Food Canada. Publication 1646 (Revised0. 187 p. Lévesque, M., Morita, H., Schnitzer, M., Mathur, S. P. 1981. Les propriétés physiques, chimiques et morphologiques de quelques tourbes du Québec et de l’Ontario, Agri. Can. 74 p. Parent, L. E., Millette, J. A. and Mehuys, G. R. 1982. Subsidence and erosion of a Histosol. Soil Sci. Soc. Am. J. 46: 404-408.

Predicting runoff dissolved P losses: which soil test is best for neutral to alkaline soils? CLAY SAWKA1, DON FLATEN1, XUDONG WANG1, WOLE AKINREMI1 AND RANJAN SRI RANJAN2 1

Soil Science Department, University of Manitoba, Winnipeg MB R3T 2N2 Biosystems Engineering, University of Manitoba, Winnipeg MB R3T 5V6 *[email protected]

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Key words: P runoff, degree of P saturation, soil test P Eutrophication in water bodies such as Lake Winnipeg has been linked to increased concentrations of phosphorus (P). In Manitoba (Canada) the Lake Winnipeg Stewardship Board has reported that agricultural practices contribute approximately 15% of Manitoba's portion of the P loading into Lake Winnipeg. The objective of our study was to evaluate four different soil test methods and eight methods of determining degree of P saturation to predict P loss in laboratory simulated runoff from neutral to alkaline soils. Most of the phosphorus losses from Manitoba’s agricultural land is in the form of dissolved P (Glozier et al., 2006 and Sheppard et al., 2006). In our study, Olsen, Modified Kelowna, Mehlich-3 and water extractable soil test P concentrations were strongly related to the concentrations of total dissolved P (TDP) measured in runoff from the coarse and medium textured soils. The R square values for these tests and soils ranged from 0.72 to 0.92, with water extractable P showing the strongest relationship with TDP concentrations in the initial 30 minutes of runoff. However, in the fine textured soils the relationships with runoff TDP declined substantially, with Olsen P showing the strongest relationship, accounting for 77% of the variation in runoff TDP. Olsen P was also the soil testing method most strongly related to runoff TDP when considered across all soils, showing a very similar relationship for both textural groups. Within each textural group, several DPS methods were reasonably well related with TDP concentrations in runoff. However, due to different relationships between soil DPS and runoff TDP for each textural group, the DPS methods were not strongly related to runoff TDP across all soils. Therefore, although the Olsen soil test is not the most accurate method for predicting runoff TDP losses from Manitoba's coarse textured soils, this test was the strongest predictor of TDP losses across a broad range of soils, especially fine-textured soils where the risk of runoff and P loss is greatest. Several DPS methods show promise for predicting P losses within textural groups, but need further refinement for use with neutral to alkaline soils across a range of soil textures. Reference List Glozier, N.E., J.A. Elliot, B. Holliday, J. Yarotski, and B. Harker. 2006. Water quality characteristics and trends in a small agricultural watershed: South Tobacco Creek, Manitoba, 19922001. Sheppard, S.C., M.I. Sheppard, J. Long, B. Sanipelli, and J. Tait. 2006. Runoff phosphorus retention in vegetated field margins on flat landscapes. Can. J of Soil Sci. 86:871-884.

Forms and cycling of phosphorus in Saskatchewan soils as affected by tillage system JEFF J. SCHOENAU1, P.QIAN1, M.GREVERS1 AND G. LAFOND2 1

Department of Soil Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK S7N-5A8 Agriculture and Agrifood Canada, Indian Head, SK S0G-2K0 [email protected]

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Keywords: phosphorus, no-till, strategic tillage, nutrient cycling, soil fertility Introduction: There is a need to address unresolved issues in the relationship between tillage and phosphorus availability in Saskatchewan soils. The objective of this paper is to provide insight into how low disturbance direct seeding (no-till) system in Saskatchewan impacts phosphorus availability. This is accomplished by reviewing research that addresses the initial stages (1 yr), short-term (5yr) versus long term (25 yr), and what happens to P availability when a long-term no-till soil receives a cycle of tillage. Initial Stages: The effect of pre-seeding tillage with a heavy duty cultivator: fall + spring (CT); spring only (MT) and no-till (NT) on pea stubble was examined at sites in the Brown and Black soil zone. The sites were under conventional tillage previously. In this study, supply rates of nitrate, phosphate and sulfate were measured using PRS anion exchange membrane probes placed in PVC cylinders in the field. In general for the two sites over the two years, the supply of available phosphorus as affected by tillage was: NT > MT> CT. Since this was the first year of the tillage treatments, the higher supplies of soil phosphorus were attributed to higher soil moisture content under no-till that enhanced the ability of P to move by diffusion in the soil. Short-term versus Long-Term: To reveal the effects of adopting low disturbance direct seeding on P availability over a longer time frame, five year (short-term) and twenty-five year (long-term) no-till plots were sampled in the Black soil zone at Indian Head, SK. This comparison revealed significantly higher supplies of available nitrogen as nitrate and also higher supplies of available phosphorus after 25 years of no-till compared to 5 years. In a sequential P fractionation, readily bioavailable P forms including resin and bicarbonate extractable P were increased in the long-term no-till soils. The results of the soil P supply measurements were consistent with observations at this site that crops grown on the long-term no-till soil were not as responsive to added P fertilizer. Imposing a Cycle of Tillage on a Long term No-till Soil: A cycle of tillage was imposed on long-term (10 yrs +) no-till soils at sites in the Brown, Black and Gray soil zones. Following tillage treatment, cores of soil (0-15 cm) were taken from each plot and segmented into 0-5 cm, 5-10 cm and 10-15 cm depth increments and extractable (modified Kelowna) P concentrations determined. Grain yield and P uptake in the crop were also assessed. The mixing by the tillage operation reduced the stratification. However, there was no large effect on P availability as revealed in similar crop P uptake among treatments. Conclusion: The no-till systems that were evaluated appear to be associated with increased soil P availability in the short and long-term, with effects that accrue over time. Stratification of P as a factor affecting P availability to crops does not appear to be an issue, and tillage to address this does not seem warranted based on the results. Chemical fractionation and synchrotron spectroscopy techniques are being applied to provide additional insight into the relationship between cropping system and soil P fertility.

Determination of carbon sequestration and nitrate leaching under different irrigation and dairy manure levels in wheat (Tritcum aestivum L) on Typic Calciagrids KHURAM SHAHZAD* University of Agriculture, Faisalabad. Institute of Soil & Environmental Sciences [email protected] Nitrogen (N) losses from agriculture are negatively impacting groundwater, air, and surface water quality. New tools are needed to quickly asses these losses and provide nutrient managers and conservationists with effective tools to assess the effects of current and alternative management practices on N loss pathways. A field experiment was conducted to study the effect of different levels of irrigation and Farmyard manure on nitrate leaching in wheat (Tritium aestivum). Before sowing of wheat, all the FYM @ 0,150and 300 kg ha-1 as per the requirement of the treatments was applied on the surface and incorporated thoroughly into the soil. A basal doze of 1/3rd of required N as per treatment along with 60kg P2O5 ha-1 and 30kg K2O ha-1 was applied prior to sowing and the remaining dose of N was applied at second and third irrigation of each treatment. A control of nitrogen and FYM was included for comparison. First treatment regarding Irrigation was applied after 30, 60,100 and 125 days. Second and third treatments of irrigation was applied after 30, 60, 80,100,125 and 18, 36, 60, 80,100,125 days simultaneously. Samples for nitrate analysis was collected with auger before sowing and at harvest from six different layers (0-5, 5-10, 10-30, 30-60, 60-90 cm). Samples was collected in each replication. Core sampler was use to determine the characteristics of soil e.g. soil texture, pH, bulk density, field capacity and permanent wilting point, organic carbon, available N, available P and available K. The yield parameters related to root weight, root length, root breath, plant leaf biomass and protein contents was calculated for each treatment after harvesting of wheat. Rate of carbon sequestration was analyzed by determining the organic matter contents.The data obtained was analyzed statistically by using Fisher s analysis of variance technique and difference among treatment means was compared by using least significant difference test (LSD) at 5% probability level.

Estimating forest soil carbon and nitrogen stocks with double sampling for stratification CINDY SHAW1, JIM BOYLE2, AND A.Y. OMULE3 1 Canadian Forest Service, Northern Forestry Centre, 5320 122 Street, Edmonton,AB, T6H 3S5 2 Forest Resources, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331-5703 3 Agro Forestry Limited, 1564 Granada Crescent, Victoria, BC, Canada V8N 2B8

[email protected] Keywords: forest soil, sampling, humus forms, carbon, nitrogen Precise and accurate estimation of C and N in forest soils is important for monitoring long-term site productivity and carbon stock changes. However, obtaining such estimates remains a major challenge, especially because of high natural variability in the forest floor. Although most researchers have used simple random sampling (SRS) for within-plot soil sampling, double sampling for stratification (DSS) can be used to decrease costs, increase precision, and increase power. Estimates of C and N stocks based on DSS were compared with those estimated by SRS, in the humus forms of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Cascade Mountains of Oregon, USA. Generally, DSS was 1.34 to 5.11 times more efficient than SRS for total C, and 1.07 to 2.00 for total N. Coefficients of variation estimated from DSS were about one-half of those estimated by SRS and reported elsewhere in the literature. The cost for sampling using DDS was one-third to one-half of that for SRS, depending on the number of strata used. Costs were reduced because fewer samples were required using DDS to provide the same precision as SRS. The DSS design was more powerful than SRS and could detect smaller changes than SRS with the same number of samples. Results suggested that the most efficient design for total C would use two strata where samples were allocated proportional to variance rather than proportional to area. Overall, large gains in efficiency can be realized with a more complex within-plot sampling design, i.e. DSS, compared with SRS.

The impact of fertilization on soil enzyme activities in two coniferous forest soils JOYCE SHEN*, SUE GRAYSTON Belowground Ecosystem Group, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4

[email protected] Keywords: forest fertilization, coniferous forests, enzyme activity, litter decomposition The response of litter decomposition to N fertilization has been inconsistent. Such inconsistent observations seem to be related to litter lignin contents and soil microbial enzymes involved in the decomposition process. To better understand the effects of fertilization on enzyme activity and C sequestration, a study was conducted in the fertilized DEMO plots at the SCHIRP (Salal Cedar Hemlock Integrated Research Program) installation located between Port McNeill and Port Hardy (50° 36’, 127° 20’). The study contains stands of cedar and hemlock with 3 levels of N ( 0, 200 and 300 Kg N/ha ) and 3 levels of P fertilization ( 0, 100, 100 + micronutrients). Samples of forest floor and mineral soil were taken from each plot (composite of 5 soil cores) from Aug 12 to Aug 16, 2007. The activities of enzymes involved in breakdown of cellulose (cellobiosidase), chitin (1, 4- β -Nacetylglucosaminidase) and organic P (phosphatase) were assayed using fluorescent method. Activity of the lignin-degrading enzymes, phenol oxidase and peroxidase was determined using colorimetric assays. Based on the analysis to date, soil enzyme activities in the organic layer were significantly different from mineral layer. Meanwhile, forest type had a significant impact on enzyme activities. When it came to treatment effect, phosphatase activity was higher in plots that did not receive P fertilization, while cellobiosidase activity was generally higher in plots that did not have N fertilization.

Net CO2 exchange at the forest floor: effects of hybrid poplar stand age and land uses ZHENG SHI*1, BARB THOMAS1,2, SCOTT CHANG1 1

Dept. of Renewable Resources, 4-42 Earth Science Building, University of Alberta, Edmonton, Alberta, T6G 2E3; 2 Alberta-Pacific Forest Industries Inc., Box 8000, Boyle, Alberta, T0A 0M0 [email protected] Keywords: net CO2 exchange, forest floor, land uses, hybrid poplar Abstract: Net CO2 exchange was measured at the forest floor in three different aged hybrid poplar stands (Populus deltoids × Populus × petrowskyana var. walker; 3, 6, and 14 years old in 2007) and two different land uses — Barley and Walker poplar (Populus deltoids × Populus × petrowskyana var. walker), in northern Alberta, Canada. Continuous measurements were made every 2 hours using an automated chamber system for four months between early June and early October, 2007. The measurement chambers were transparent and thus rates of soil respiration were measured at night, and net CO2 exchange was measured in the daytime as CO2 efflux was reduced by photosynthetic uptake by forest floor vegetation during the day. Over the 4 month period in different aged hybrid poplar plantations, July had the largest while October had the smallest CO2 fluxes, except for the small flux in the 3-year-old hybrid poplar plantation which happened in early September. Under different land uses, July had the largest CO2 fluxes for both barley and Walker poplar, while late August or early September the smallest fluxes. The mean rate of CO2 fluxes during the growing season increased across stand ages, with rates being 0.35, 1.57 and 1.93 µmol CO2 m-2 s-1 in the 3, 6 and 14-year-old hybrid poplar plantations, respectively, and mean rate of CO2 fluxes during the growing season were greater in the barley plots (1.30 µmol CO2 m-2 s-1) than in the Walker poplar plots (0.56 µmol CO2 m-2 s-1) two years after the agricultural land was converted to a poplar plantation.

Soil ecology science: challenges for promoting a sustainable planet SUZANNE W. SIMARD University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4 Keywords: climate change, soil feedbacks, species migration, exotic invasions Soil ecology science has contributed greatly to our understanding of natural soil patterns and processes, the impact humans have had on them, and management approaches useful in soil conservation and restoration. With exponential human population growth over the past 100,000 years, soil science has also played an important role in revolutionizing ecosystems, from sustainable hunter-gatherer systems, to self-sufficient farming systems, and, more recently, to globally trading industrial, agricultural and forest harvesting systems. This revolution has had multiple feedbacks, however, with ecosystem effects that occur at increasingly larger scales, to where humans have influenced the global climate. Global climate change has the potential for disastrous effects on ecosystems, biodiversity and genetic diversity that could lead to rapid mass extinctions (Thomas et al. 2004). We need only look at climate model predictions for species migrations over the next century to understand the enormity of ecological problems that lay ahead (Hamann and Wang 2006). In addition to the Arctic and Antarctic, it is predicted that terrestrial ecosystems most threatened by climate change will include coniferous forests, grasslands, deserts, wetlands, and alpine and coastal areas -- the very ecosystems in which we live (Walther et al. 2002). The basic understanding of soil ecology that humans have developed provides an invaluable baseline for predicting and managing these changes. However, ecological sciences, including soil ecology, need to refocus toward interdisciplinary, large-scale, international research that helps ensure a future where humans live sustainably within ecosystems. Although I am reluctant to come to terms with this myself, this research needs to acknowledge that, with exponential human population growth, managed ecosystems and intensive resource exploitation will define our future. To rise to this urgency, soils research must be closely linked to solutions through environmental policy. In my talk, I review what I think are some important soil ecology research issues for enhancing resilience of terrestrial ecosystems to climate change. Of basic importance to soil ecologists is understanding the changing roles played by below- and aboveground biota in feedbacks among climate change, disturbance regimes, carbon and nutrient dynamics (e.g., Kurz et al. 2008), and biodiversity itself. Soil organisms, for example, will play crucial roles in facilitating or limiting native and exotic plant species migrations in response to climate change, which is one of the complex mechanisms (along with evolutionary adaptation and phenotypic plasticity) by which species and ecosystems will respond (Geber 2008). Here, identifying, protecting, managing, and understanding changing processes in belowground functional groups and keystone species will be as important for preventing native diebacks (McDowell et al. 2008) or exotic invasions as they are for facilitating species migrations (Reinhart and Callaway 2006) and reorganizing ecosystems. Similar research is needed to address the crucial role soil organisms play in stabilizing soils (Rillig and Mummy 2006), mitigating nutrient losses and sequestering carbon as disturbance regimes change. I illustrate these points with examples of research conducted within my group. Reference List Geber, M.A. 2008. To the edge: studies of species’ range limits. New Phyt. 178: 228–230. Kurz, W.A., et al. 2008. Mountain pine beetle and forest carbon feedback to climate change. Nature 452: 987-990. McDowell, N., et al. 2008. Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought? New Phyt. 178: 719–739 Reinhart, K.O., Callaway, R.M. 2006. Soil biota and invasive plants. New Phyt. 170: 445-457. Rillig, M.C., Mummy, D.L. 2006. Mycorrhizas and soil structure. New Phyt. 171: 41– 53. Thomas, C.D., et al. 2004. Extinction risk from climate change. Nature 427: 145-148. Walther, E.R., et al. 2002. Ecological responses to recent climate change. Nature 416: 389-395.

The status of soil survey in Manitoba: an exciting future DIANE M. SMITH¹, LYNN MANAIGRE², PETER HALUSCHAK², RONGGUI WU¹, YI ZHANG¹ ¹Manitoba Agriculture, Food and Rural Initiatives, 36 Armitage St., Minnedosa, MB R0J 1E0 ² Manitoba Agriculture, Food and Rural Initiatives, 13 Freedman Cres. Winnipeg, MB R3T 2N2 [email protected] Keywords: soil survey, MAFRI In response to the growing need for detailed soil survey, Manitoba Agriculture Food and Rural Initiatives has recently rejuvenated the Soil Survey program. The objective of the program is to expedite the continued mapping of soils to ensure the best possible decisions are made about land use and land management in Manitoba. In addition to its implementation, the Soil Survey Program has adopted new technologies to enhance the program. The Soils Information Management System (SIMS), an electronic data entry tool, has been developed to facilitate data collection in the field and the laboratory, and digital stereoscopic viewing imagery using PurVIEW has been incorporated into the program. The Soil Survey program also participates in the development of provincial programs and policies including land use, land management, the validation of national environmental risk predictive models to determine their ability to predict risk at a watershed and on-farm scale, validation of beneficial management practices (BMPs) in cooperation with the provincial Watershed Evaluation of Beneficial Management Practices (WEBs) program, and developing strategies to address Ecological Goods and Services (EG&S) policy and programs.

Effect of soil forming processes on the distribution of soil organic carbon in a dissected, unglaciated landscape in west-central Yukon C.A.S. SMITH1, P.T. SANBORN2 AND J.D. BOND3 1

Agriculture and Agri-Food Canada, P.O. Box 5000, Summerland, BC V0H 1Z0 University of Northern British Columbia, 3333 University Way, Prince George, B.C. V2N 4Z9 3 Yukon Geological Survey, Energy Mines and Resources, P.O. Box 2700, Whitehorse, YT Y1A 2C6 [email protected] 2

Keywords: Cryosols, colluviation, unglaciated, soil organic carbon Soils were observed from recently excavated mineral exploration trenches on a range of slope aspects and positions within the discontinuous permafrost zone of the unglaciated Klondike Plateau in central Yukon. Soil parent materials are composed of variable thicknesses of loess and colluvium. In general, westerly and southerly facing slopes and ridge crests are free of near-surface permafrost and support the development of Dystric Brunisols with thin (<10 cm) surface litter layers and low organic C values throughout the underlying mineral horizons (Bond and Sanborn 2006). In strong contract, soils formed on slopes with northerly and easterly aspects and in lower slope positions contain nearsurface permafrost and horizons are organic matter-rich throughout the profile (Tarnocai et al. 1993). Trenches contoured across these permafrost-affected slopes exposed both the active layer and frozen subsurface horizons to a depth of approximately 2m. The soils exhibited unique features of both cryoturbation and colluviation, and were classified as Histic Dystric Turbic Cryosols (Soil Classification Working Group 1998). Most striking was the predominance of organic matter within the upper 150 cm of permafrost. Poorly to moderately well decomposed peats make up buried O horizons. Permanently frozen mineral soil horizons typically contain 3 to 9% finely dispersed organic carbon. Fragments of wood, roots, and charcoal were common in all horizons within the top of permafrost with no real trend with depth. Radio carbon dating of charred wood fragments and peat from within this colluviated parent material yielded dates from 350 to 3,680 years BP indicating active Late Holocene turbation in the soil. The charred nature of much of the wood would suggest that forest fires periodically and regularly thaw the top of permafrost and initiate slope movement with resultant incorporation of surface organics. Based on our observations of vertical profiles, incorporated peats may comprise up to 10% of the volume of the upper 100 cm of permafrost. These hillsides may store up to 70 kg of organic carbon per m2 of surface. The soils occur extensively throughout the Klondike Plateau ecoregion of west-central Yukon. Reference List Soil Classification Working Group 1998. The Canadian System of Soil Classification. Agric and Agri-Food Can. Publ.1646 (revised). 187pp. Bond J.D. and P.T. Sanborn 2006. Morphology and geochemistry of soils formed on colluviated weathered bedrock: Case studies from unglaciated upland slopes in west-central Yukon. Yukon Geological Survey Open File 2006-19. 70pp.

High spatial-temporal thermal remote sensing for updateble and detailed soil survey databases AIMAN S. SOLIMAN *1, RALF B. BROWN 2 AND RICHARD J. HECK 1 1

Department of Land Resource Science, University of Guelph, Guelph ON, Canada N1G 2W1 School of Engineering, University of Guelph, Guelph ON, Canada N1G 2W1 [email protected] 2

Keywords: thermography, high spatial-temporal remote sensing, modern soil survey methods Soil classification systems are based on soil survey and field observation especially at a detailed level. However, conventional field survey techniques require a relatively long time to complete a single survey. Also, use of remote sensing is constrained by the trade-off between spatial and temporal resolution in addition to economic visibility. A unique aerial survey experiment was conducted at St.Catharines, southern Ontario, where four thermal images with high spatial resolution, 60 cm per pixel, and high temporal rates, image every two hours from sunrise to sunset, were collected from a light aircraft. Data collected were used to calculate three images describing heating rates for the morning, noon and prior to sunset. Discussions are presented on the interpretation of false colour composites constructed from the three heating rates images as well as for the application of this new survey technique for detailed soil databases on vineyards.

Soil and vegetation changes over 15 years at a reclaimed coal mine in the aspen parkland region of Alberta TREMAYNE S. STANTON-KENNEDY*1, M. ANNE NAETH1, KAREN LANDMAN2 1

Department of Renewable Resources, University of Alberta, Edmonton, Alberta School of Environmental Design & Rural Development, University of Guelph, Guelph, Ontario [email protected]

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Keywords: reclamation, restoration, coal mine, soil changes To evaluate the outcomes of reclamation design, the changes in soil and plant community on an unmanaged, 15 year old reclaimed site were analysed and compared with an undisturbed reference location. Patterns were analysed using MRPP while change was measured with rmANOVA. Plant species were poor predictors of selected soil properties. Percent soil organic carbon increased (p = 0.032), while soil pH did not change. Overall plant community composition did not change in proportion of cover between a priori groups of seeded/volunteer species or between native/introduced species. Individual species did vary in amount of cover change between 1993 and 2007. A linear regression of richness versus area covered by native species determined that the Shannon index is not a suitable measurement for monitoring plant community trajectories towards the reference ecosystem.

Chemical analysis of two soils within recently dehydrated ponds and one soil bordering a saline pond in the Kamloops Region of British Columbia JOHN STARCHUK* Thompson Rivers University Box 3010, 900 McGill Road, Kamloops, BC., Canada V2C 5N3 [email protected] Kamloops lies in a semi-arid region of the Thompson Valley in which the proper conditions of low precipitation and warm climate allow for the development of saline ponds. This study aims to chemically analyze and classify the soils that surround these and recently dried-up ponds. One dry-pond bed shows the characteristics of Vertisolic soil, which along with chemically determining its physical and chemical characteristics, will have its clay composition extracted and sent to UNBC for x-ray diffraction. Ponds will be chosen based on previous biological studies done. The aim of this project is to classify these soils and develop a greater understanding of their properties and interactions with the surrounding environment. Reference List Fraser Basin Council: Regional Summary http://www.shim.bc.ca/atlases/fbc/ss3/Regional_Summary.html, Accessed: September 12, 2007 Agriculture and Agri-Food Canada http://www.agr.gc.ca/nlwis-snite/index_e.cfm?s1=pub&s2=hs_ss&page=14, Accessed: September 10, 2007 Brady N.C.; Weil R.R, The Nature and Properties of Soils 12th ed., 1999, p 378 – 401 Vaughan, Ian; Soil Analysis Bordering Three Saline Ponds in the Surrounding Kamloops Area; Chem 448: Directed Studies final report; Thompson Rivers University; April, 2007. Ritter, M. E., The Physical environment: An Introduction to Physical Geography; http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/soil_systems/soil_orders_p1.html, Site visited: September 17, 2007 Site last updated: June 21, 2007

A system for generalizing soil maps in southwestern Ontario BEN STEWART, DAVID KROETSCH National Land and Water Information Service: Agriculture and Agri-food Canada K.W. Neatby Building, Room 1136, Carling Ave. Ottawa, Ontario K1A-0C6 [email protected]; [email protected] Keywords: generalization, component mapping, association, automation The Ontario Ministry of Agriculture and Rural Affairs (OMAFRA) and Agriculture and Agri-Foods Canada (AAFC) are currently working together to develop an integrated, seamless coverage of Soils Data for agricultural lands in Southwestern Ontario. In support of their effort, mapsheets for several counties are being generalized from a scale of 1:25,000 to 1:50,000. In Ontario, until now, generalization has been accomplished using semi-automatic, or manual processes. As a consequence, the work has not been entirely reproducible. Confirmation and validation has been a challenge. The underlying premise, of the present work, is that processes for soil development have been adequately described and summarized by pedologists in the field, using the concept of the 'series'. An automated generalization of component maps can be achieved by sorting series and building associations, based on proximity. The similarity between components - upon which the process is based - can be computed in a Relational Database System (RDBS), with consistency. The process is fully reproducible, and can be applied to a range of problems. The current release of the Generalization Software, referred to as the "General Extrapolation and Convergence Tool" (GECT), generalizes component-based soil maps to any scale using a pre-defined list of associations; where scale is based upon the requirements for polygon delineation as described in "A Soil Mapping System for Canada: Revised" (The Expert Committee on Soil Survey, 1981). The GECT works by ‘electing’ polygon pairs (comprised of 'donors' and 'recipients') based on a coefficient of similarity. A minimum allowable value for the coefficient decreases as the system cycles - the lower their value, the longer polygons will wait for a better match. Non-pedologic factors for convergence are also introduced, in a step-wise manner, as the bar for a successful candidacy lowers. All donors, are eventually consumed. The GECT maximizes the information stored in the 'recipient' label by summarizing data, and by utilizing unpopulated component slots. It re-defines, and re-labels polygons, as it cycles. The GECT retains donor attributes together with factors for decisionmaking to support fine-tuning and verification of the output. Work is on-going to complete a full version of the GECT refered to as the 'Polygon Building Tool' (PBT), which will compute a list of associations dynamically, by analyzing the target map. This full version, will render current and accurate vector maps from the output of digital predictive mapping technology while filtering out errors and random variation, at scale.

Reference List: Expert Committee on Soil Survey: Mapping System Work Group, AAFC 1981. A Soil Mapping System for Canada: Revised. Land Resource Research Institute Contribution # 142, Research Branch, Agriculture Canada. Ottawa, ON.

An innovative, interactive teaching tool for metapedogenesis RACHEL A. STRIVELLI*1, MAJA KRZIC1, LES LAVKULICH1, CHRIS CROWLEY 2 1

Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4 Office of Learning Technology, University of British Columbia, Vancouver, BC V6T 1Z4 [email protected]

2

Keywords: Teaching of soil science, soil formation, soil processes, Podzols, land-use impacts Although there is considerable rhetoric about the impacts of human activities on soil quality (Yaalon and Yaron 1966; Goudie 2006), the effects are poorly communicated (Lal 2007). Innovative teaching approaches to aid the understanding of anthropogenic impacts on soil quality are needed if the goal is to conserve this essential resource. University students are in a prime setting for this educational process (Holland 2006). To aid in this goal a teaching tool is being developed that explains soil formation and the human impact on soil formation processes that affect soil characteristics and properties. This initiative commenced in the fall of 2007. The teaching tool will illustrate the impacts of land-use practices on soil quality on UBC campus. The tool will include instructional technologies, as well as soils data from 1970 and 2005 (Lavkulich and Rowles 1971; Shanahan 2006), archival photos, geology maps, and historical narratives. The objectives of this project are to (1) describe the pedogenesis of most common soil types on the UBC campus, (2) evaluate long-term impacts of onetime logging, multiple logging events, forest clearing, and on-going cultivation on soil processes on UBC campus, and (3) evaluate to what degree human impacts are changing soil processes and to argue for/against the designation of a sixth factor of soil formation (metapedogenesis). The tool will be complimentary to Forestry, Agroecology, and Geography courses that address issues of land-use impacts on soils. Upon completion, the tool will be used in several soil science and natural resources courses offered at UBC. In addition, the tool will be made available to instructors at other universities in British Columbia (e.g., UNBC, TRU, SFU). Reference List Goudie, A. 2006. The Human Impact on the Natural Environment. 6th ed. Victoria, BC: Blackwell Publishing. 17. Holland, K. 2006. How does a virtual field trip compare to the real thing? On-Line Classroom Newsletter by MAGNA, Nov 2006. Available at www.magnapubs.com/issues/magnapubs_oc/6_11/news/599509-1.html [Oct 16, 2007]. Lavkulich, L.M. and C.A. Rowles. 1971. Effect of different land use practices on a British Columbia Spodosol. Soil Science. 111 (5): 323-329. Lal, R. 2007. "Revitalizing Soil Science Programs at the Land Grant Institutions." CSA News. 29, V52N07, 29-31. Shanahan, P. 2006. Metapedogenesis of Podzols on University Endowment Lands, BC. BSc. Geology Thesis, University of Plymouth, UK. Yaalon, D.H. and B.Yaron. 1966. "Framework for Man-Made Soil Changes-An Outline of Metapedogenesis." Soil Science. 102 (4): 272-277.

Got the climate change blues? Soil properties may impact mycorrhiza communities, early growth and relocation success of whitebark pine LINDA E. TACKABERRY1, HUGUES B. MASSICOTTE1, D. SCOTT GREEN1 1

Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9

[email protected] Keywords: Pinus albicaulis, climate change, ectomycorrhizas, adaptive growth traits, migratory potential Whitebark pine (WBP, Pinus albicaulis Engelm.) is a remote subalpine conifer recently Blue-listed in British Columbia, Canada. The species is vital to slope stabilization, plant succession and watershed protection – conditions critical to forest management and silviculture practices on upper slopes. In addition to its decline due to white pine blister rust and mountain pine beetle threats, predicted climate warming might also lead to replacement of WBP forests, changing plant and wildlife diversity, snow capture and watershed hydrology. To survive, WBP may need to expand naturally or by intervention into alpine areas, or north in latitude. Roots of WBP must form symbiotic associations (ectomycorrhizas) with soil fungi that facilitate water and nutrient uptake; however, little is known of the biology of WBP root-soil interactions that could provide important information for the conservation or relocation of WBP, given its limited migratory potential. A greenhouse bioassay will examine how subalpine soils (with WBP) and alpine soils (presently with no WBP) impact seedling growth and root-fungal communities. To explore limits of location and population differences, soils from multiple locations and seed from north-south and east-west WBP populations will be tested. Seed stratification protocols and experimental design will be discussed. Within the context of climate change, study findings will extend our understanding of how WBP may respond to natural or assisted relocation under genetic, soil microbial, and elevation shifts. Where risk of ecological impacts is high, proactive management in high elevation forests might sustain threatened species and ecosystem function.

Ah horizons formed by atypical processes (erosion and deposition, microcolluvial action and transfer via solution) — do they warrant descriptive and taxonomic recognition? AARON S. TROWBRIDGE1 Bulkley Valley Centre for Natural Resources Research and Management, Box 4274, Smithers, BC, V0J 2N0 [email protected] Keywords: soil organic matter, Ah horizons, taxonomy, organic decomposition, geomorphic processes Organic matter incorporation is an import soil formation process with implications for soil structure, nutrient availability, soil biodiversity, and carbon sequestration. Traditional taxonomic definitions for Ah horizon development stress the zoogenic component of decomposition and incorporation. However, there are several other mechanisms for transfer of organic material into surface mineral horizons that are more distinctly geomorphic in process. I describe these processes as: (1) micro-scale erosion and deposition, (2) micro-scale colluviation, and (2) transfer via solution in saturated soils. I argue that these processes result in distinct morphologies from zoogenic processes, and warrant descriptive and taxonomic recognition.

Humus forms and forest soils — a case for integrating humus form description and taxonomy into the Canadian System of Soil Classification AARON S. TROWBRIDGE1 1

Bulkley Valley Centre for Natural Resources Research and Management, Box 4274, Smithers, BC, V0J 2N0 [email protected] Keywords: humus forms, forest soils, taxonomy, Canadian System of Soil Classification Humus forms are intimate associates of soil and vegetation; they can serve as both facilitator of community structure and composition, as well as an indicator of site character. The description and classification of humus is a central tenant to many natural resource management applications, for example the assessment of site quality, effects of prescribed fire, global carbon cycles, tree seedling establishment, or soil biodiversity. In particular, humus forms are important for understanding nutrient cycling and seral dynamics in forests. There is considerable international interest to emphasize humus form research and taxonomic integration, including a call to revise and expand the Food and Agriculture Organization of the United Nations (FAO) “Topsoil Characterization” (Broll et al. 2006), and to develop integrated European humus form systematics (Jabiol et al. 2004). I argue that humus form taxonomy needs to be formally integrated into the Canadian System of Soil Classification to (1) support wider use and understanding, and (2) to facilitate the integration of future research into a taxonomic system. This argument is supported by both domestic demand, and the need to maintain and build on the international recognition garnered by earlier Canadian humus form work (Green et al. 1993). Reference List Broll, G., Brauckmann, H., Overesch, M., Junge, B., Erber, C., Milbert, G., Baize, D. and Nachtergaele F. 2006. Topsoil characterization - recommendations for revision and expansion of the FAO-Draft (1998) with emphasis on humus forms and biological features. J. of Plant Nutr. and Soil Sci. 169:453-461. Green, R. N., Trowbridge, R. L. and Klinka, K. 1993. Towards a taxonomic classification of Humus forms. Society of American Foresters. Forest Science-Monograph 29. Jabiol, B., Englisch, A., Hager, M., Katzensteiner, K. and de Wall, R. 2004. Towards an European classification of terrestrial humus forms. http://www.bodenkunde2.unifreiburg.de/eurosoil/abstracts/id372_Jabiol_full.pdf (Accessed April 24, 2008).

Phenol versus salicylate: two colourimetric methods for soil ammonium-N measurement JESSICA J. D. TURNBULL*, JOHN D. LAUZON, GARY W. PARKIN Department of Land Resource Science, University of Guelph, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 [email protected] Keywords: ammonium-nitrogen, phenol, salicylate, potassium chloride The colourimetric method of ammonium-nitrogen (NH4+-N) analysis using phenol has been widely accepted throughout soil sciences. However, phenol has many associated negative health hazards including; epidermal burns, ocular inflammation, respiratory damage, irritation of the digestive tract, and in extreme cases, death (Fisher Scientific 2005). The salicylate method is also available to colourimetrically measure NH4+-N. While, salicylate is less dangerous (Fisher Scientific 2008), the associated method has not been as widely used. Five hundred soil samples were collected from a manure application method and timing trial over the course of a growing season in 15 cm increments to a depth of 75 cm. Exchangeable NH4+-N was extracted from soil using 2 M KCl. The extracts were simultaneously analyzed for NH4+-N using the phenol method (Lachat Instruments 2001) and the salicylate method (Lachat Instruments 2003) using flow injection analysis (Lachat instruments, QuickChem® FIA+ 8000 series). The objective is to compare reliability of the salicylate method as compared to the phenol method. If comparable, this study will promote the phasing out of phenol in laboratories for the purpose of NH4+-N analysis because of the associated negative health effects. Reference List Lachat Instruments 2001. QuikChem® Method 12-107-06-1-B. Determination of ammonia by flow injection analysis. Milwaukee, WI, USA. Lachat Instruments 2003. QuikChem® Method 12-107-06-2-A. Determination of ammonia (salicylate) in 2 M KCl soil extracts by flow injection analysis. Milwaukee, WI, USA. Fisher Scientific 2005. Material Safety Data Sheet, Phenol Liquefied (80% solution in water). Loughborough, Leics, UK. Fisher Scientific 2008. Material Safety Data Sheet, Salicylic Acid Sodium Salt. Fair Lawn, NJ, USA.

Contribution of snowmelt to soil moisture replenishment and storage in the Cariboo Mountains of British Columbia TULLIA UPTON*1, STEPHEN DÉRY2 1

University of Northern British Columbia- M.Sc. Student NRES 3333 University Way Prince George, BC,V2N 4Z9 [email protected]

2

University of Northern British Columbia- Assistant Professor 3333 University Way Prince George, BC,V2N 4Z9 [email protected]

Keywords: soil moisture, climate predictions, climate change, reflectometer The IPCC (2007) projects that 21st century warming will be more pronounced at high elevations and at high northern latitudes. Soils form the interface between the earth and the atmosphere and hence soil moisture is a key component of the global climate system. It is therefore essential to know how climate change may affect the replenishment and storage of soil water derived from snowmelt. It was found that soils in Finland do not tend to freeze below a 10-cm depth (Sutinen et al. 2007) suggesting that melt water could infiltrate the soil during winter and contribute to groundwater recharge. It has also been speculated that soil moisture can be used to predict climatic variability in mid-latitudes at seasonal and perhaps inter-annual time scales (Koster and Suarez, 2001). As such, the importance of having ground-based observational data of soil moisture has become more apparent, especially in areas where there are no existing data and where climate change is expected to be more extreme. Since June 2006, the Northern Hydrometeorology Group has deployed 5 meteorological monitoring stations throughout the Cariboo Mountains in the Central Interior of British Columbia. These stations have sensors that measure hydrometeorological variables including soil moisture. . Reflectometers that measure soil moisture throughout the winter provide valuable information about melt water infiltration and water movement in soils covered by a deep snowpack. Results from 2 sites for the 2007/08 winter season will be presented and discussed. It is hypothesized that soil moisture anomalies in the autumn will persist through the winter to determine infiltration rates of meltwater during spring. Our results will help to determine whether or not the soil moisture content changes throughout the winter and how precipitation in the fall affects the ability of the soil to recharge its water supply through the winter into the next spring.

Reference List

International Panel on Climate Change. 2007. Climate Change 2007: The Physical Science Basis. Cambridge University Press, Cambridge, UK. Koster, R.D. and M.J. Suarez. 2001. Soil Moisture Memory in Climate Models. Journal of Hydrometeorology. 2:558-570. Sutinen, P., Hänninen, P. and A. Venäläinen. 2007. Effect of mild winter events on soil water content beneath snowpack. Cold Regions Science and Technology. doi:10.1016/j.coldregions.2007.05.014.

The impact of lentil and pea seeding rates on nitrogen fixation and subsequent N2 benefits in organic farming BOLDSAIKHAN USUKH*1, FRAN WALLEY2, DIANE KNIGHT3 1

M.Sc. Candidate, Department of Soil Science, University of Saskatchewan, 51 Campus Dr. Saskatoon, SK S7N5A8; Phone: (306) 966-4293; E-mail: [email protected] 2 Supervisor, Department of Soil Science, University of Saskatchewan, 51 Campus Dr. Saskatoon, SK S7N5A8; Phone: (306) 966-6854 3 Co-Supervisor, Department of Soil Science, University of Saskatchewan, 51 Campus Dr. Saskatoon, SK S7N5A8; Phone: (306) 966-2703 [email protected] Keywords: seeding rate, pea, lentil, organic farming Because of the rapidly increasing number of organic farms and the area managed organically, there is a demand for new recommendations for pulse seeding rates that will meet the needs of organic farmers. Although seeding rates are well established for conventionally grown lentil and pea, recommendations for organically grown pulses are not well known. Importantly, it is not known what impact different seeding rates might have on N2 fixation. This is important consideration in organic systems where N fertilizers are not used in any part of rotation (Stevenson and van Kessel, 1996). Therefore, farmers want to maximize N2 fixation to increase the yield of pulses crop and increase N supply to the subsequent crops in rotation. The study is examining the relationship between seeding rate of lentils and peas and N2 fixation, and the benefits of those pulses to the succeeding crop for cereal-dominated rotations on organic farms in Central Saskatchewan between 2005 and 2007. Field peas (Pisum sativum cv CDC Mozart) and lentils (Lens culinaris cv CDC Sovereign) were seeded at five seeding rates: 10, 25, 62, 156 and 250 plants m-2 and 15, 38, 94, 235 and 375 plants m-2, respectively. Green manures and a summerfallow treatment were included for each crop experiment. Indianhead lentils at a density of 235 plants m-2 and Trapper field peas at a density of 62 plants m-2 were chosen as the cultivars optimal seeding densities for the green manure treatments, as determined by Lawley (2004). For estimating N fixation in each treatment, AC Elsa wheat was sown as a nonfixing reference crop. In the following year of the lentil and pea seeding rate experiments, AC Elsa wheat was sown as a test crop to assess the effect of the treatments on the succeeding crop. Preliminary results showed %Ndfa wasn’t significantly different between the treatments on both lentil and pea experiments, however, Ndfa kg ha-1 was greater on the higher seeding rates; as well, significantly greater amount of nitrogen was accumulated in the grains of succeeding wheat which was planted on stables of higher seeding rates and green manures of lentil and pea. Reference List Lawley, Y. 2004. Determining optimum plant population densities for three annual green manure crops under weedy and weed-free conditions. M.Sc. Thesis. Department of Soil Science. University of Saskatchewan, Saskatoon. Stevenson, F.C. and van Kessel, C., 1996. The nitrogen and non-nitrogen rotation benefits of pea to succeeding crops. Can. J. Soil Sci.28:735-745.

Influence of nitrogen fertilization on cucumber (Cucumis sativus L.) yield, economic value, nitrogen accumulation and apparent fertilizer-nitrogen recovery LAURA L. VAN EERD1, KELSEY A. O’REILLY1 1

Department of Land Resource Science. University of Guelph Ridgetown Campus. Ridgetown, ON N0P 2C0 [email protected] Keywords: nitrogen, vegetable, cucumber, fertilizer recovery The increase in fertilizer costs, as well as environmental concerns has fueled growers to re-evaluate their fertilizer applications in order to optimize N use efficiency (NUE) while maintaining crop yields and minimizing off-field N losses. This is particularly true for machine-harvested cucumbers (Cucumis sativus L.), which is a short season crop harvested six weeks after planting. Field trials with randomized complete block design were conducted in 2004-2006 at seven sites to 1) determine the optimal rate of preplant N in machine-harvested cucumber, 2) estimate total N budget and 3) calculate NUEs. Five N rates between 0 and 220 kg N ha-1 of ammonium-nitrate was broadcast and incorporated before seeding in early June, as well as a split application of 65 + 45 kg N ha-1 applied preplant and before the vine elongation was included. Inorganic N concentration (NO3--N and NH4+-N) was determined to 75 or 90 cm depths at planting, split N application and harvest. Six meters of the center three to five rows were hand-harvested to stimulate an once-over machine harvest. Fruit was graded to size and culls according to the industry standard and fresh weights of each grade were determined. Results were converted to a per hectare basis based on stand counts. A representative sample of 10% of each grade and above the ground shoots from five plants were used to determine total N content in the 0, 110, 220, and 65+45 kg N ha-1 treatments. In three contrasting years (i.e. cool/wet vs. warm/dry vs. average), marketable cucumber yield or yield-income response to N application was either non-responsive, or tended to be a slight positive or negative linear response. However, it was not possible to determine a recommended rate for machineharvested cucumber. Based on total N budget over all site-years, there was no difference between N treatments in crop N removal (ie N in the cucumber fruit), but the quantity of N in field after harvest as crop residue and soil mineral N was a linear relationship to N applied. Overall, the preplant and split applications of 110 kg N ha-1 were not different in overall N budget or NUE indices. Considering this, the short growing season, and the extra associated costs, the tested split application is not recommended. As expected, apparent fertilizer-nitrogen recovery ([total plant N in fertilized subtract non-fertilized control] divided by fertilizer applied) and N uptake efficiency (total plant N content divided by [soil N plus fertilizer N]) were lower at 220 vs. 110 kg N ha-1 applied preplant or split. There were no differences in plant partitioning of N between fruit and shoots at the different N treatments. Overall, these results indicate that an application rate of 220 kg N ha-1 is both environmentally and economically undesirable due to high N in the field at harvest and unnecessarily higher input costs.

Sorption and net die off of Escherichia coli and Enterococcus faecalis in uncontaminated soil samples ELISA VERMA*1, NOORALLAH JUMA1 1

M.Sc. student and Professor of Soil Microbiology & Biochemistry, respectively, Onsite Wastewater Treatment Research Laboratory, Department of Renewable Resources, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3 [email protected] Keywords: soil-based treatment systems, adsorption, die-off, fecal coliforms The at-grade wastewater effluent treatment systems are on-site private sewage systems designed to accomplish the final treatment of secondary treated effluent in soil so that water can be safely returned to the environment. Safe use of this technique relies on the successful removal of contaminants from the applied effluent by filtration, adsorption and biological activity in soil to reduce the risk of pathogen pollution into water bodies. The objectives of this study were: (1) to assess the die-off rates of two different traditional indicator organisms, E. coli and E. faecalis at 23°C, 5°C and -18°C, and (2) sorption of these organisms at 23°C and 5°C in soil samples from Ah and Bt horizons of an Eluviated Black Chernozem and Ah, Ae and Bt horizons of an Orthic Gray Luvisol. Overall results showed that net die-off rates are higher at 23°C compared to 5°C for both organisms. Although incubation at -18°C caused the highest initial die-off, viable microorganisms were found after 60 days. E. faecalis was shown to be the indicator organism with the longest life span in soil. Adsorption was higher in soil samples from Ah compared to the Ae and Bt horizons. These results are being used to assess the fate and attenuation of fecal coliforms introduced to the soil through perforated pipes laid on the surface of the soil. An understanding of these processes can lead to a better design of soil-based wastewater

dispersal systems.

Field nitrous oxide fluxes induced by soil freezing CLAUDIA WAGNER-RIDDLE1, ADRIANA. FURON1, JENNA RAPAI1, JON WARLAND1 1

Dept. of Land Resource Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1 [email protected]

Keywords: nitrous oxide flux, micrometeorological method, soil heat pulse probes, freeze/thaw cycles Winter and spring thaw nitrous oxide fluxes contribute a significant fraction of the total N2O emission budget in cold climates. Nitrous oxide fluxes from agricultural soil in Ontario were measured using a flux-gradient method over seven winter and spring thaw periods from fall 2000 to spring 2007. In Wagner-Riddle et al. (2007) we reported that non-growing season (November to April) emissions from 2000 to 2005, comprised between 30 to 90% of the annual emissions, mostly due to increased spring thaw N2O fluxes. The duration and intensity of soil freezing prior to spring thaw was quantified using accumulated degree-hours below 0°C at 5 cm depth (FDH). Nitrous oxide emissions were well correlated (r2 = 0.90) to FDH. Freezing degree-hours explained differences in spring thaw emissions observed under no-tillage, with significant reduction in N2O emissions (80% of total reduction) due to the insulating effects of the larger snow cover plus corn and wheat residue during winter. Use of in situ soil columns receiving 15N tracer during winters of 2003 and 2004 at the same site, indicated that the source of N2O burst at spring thaw was mostly ‘newly’ produced N2O in the surface layer, and not the release of N2O trapped in the unfrozen soil beneath the frozen layer (Wagner-Riddle et al., 2008). In this paper nitrous oxide emissions measured over the 2006 and 2007 non-growing seasons will be compared to our previous findings. In addition, recent measurements of freeze/thaw events identified through the use of soil heat pulse probes, as they related to N2O fluxes will be presented. Wagner-Riddle, C., Furon, A., McLaughlin, N.L., Lee, I., Barbeau, J., Jayasundara, S., Parkin, G., von Bertoldi, P., Warland J. 2007 Intensive measurement of nitrous oxide emissions from a corn-soybean-winter wheat rotation under two contrasting management systems over 5 years. Global Change Biol. 13: 1722-1736 Wagner-Riddle, C., Hu, Q.C., van Bochove, E., Jayasundara, S., 2008. Linking nitrous oxide flux during spring thaw to nitrate denitrification in the soil profile. Soil Sci. Soc. Am. J. (in press)

Applications of nitrogen K-edge XANES for analysis of whole soils and soil fractions FRAN WALLEY1, PETER LEINWEBER2, ADAM GILLESPIE1, RICHARD FARRELL1, ROB BLYTH3 1

Department of Soil Science, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK Institute for Land Use, Rostock University, Justus-v-Liebig-Weg 6, 18051, Rostock, Germany 3 Canadian Light Source Inc., 101 Perimeter Rd., Saskatoon, SK [email protected] 2

Keywords: synchrotron, unknown nitrogen, reference compounds, X-ray absorption, XANES Approximately thirty percent of soil organic nitrogen (SON) remains in unknown forms in soils. Virtually all the advanced analytical techniques available to the structural and organic chemist have been applied toward the characterization of soil organic matter and SON. Recently, synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy has been explored as a complimentary, purportively non-destructive, technique for the characterization of organic materials. This technique is sensitive to the chemical environment and oxidation state of single elements, and is thus uniquely suited to the characterization of complex environmental samples. This talk will present some applications of XANES spectroscopy at the nitrogen K-edge toward the characterization of whole soils and soil fractions.

Fitting British Columbia Vertisolic, Solonetzic and pond soils into the Canadian System of Soil Classification (CSSC) and suggestions for CSSC revisions, updates and simplification E.K. WATSON1 1

Dept of Natural Resource Science, Thompson Rivers University, Kamloops, BC. V2C 5N3 Phone: 250-371-5578, Fax 250-828-5450 [email protected] Keywords: classification, Vertisolic, Solonetzic, ponds, revisions The Canadian System of Soil Classification (CSSC) places soils into static Orders, Great Groups and Subgroups. There are certain instances where some soils are difficult to place into categories, especially at the Subgroup level. In British Columbia Solonetzic and Vertisolic soils, located adjacent to and within dehydrated saline ponds, and intergrades between the two orders are sometimes difficult to classify to the Subgroup level. There are a few reasons for this. Firstly, CSSC defined horizon designations do not always fit what is observed in the field. Secondly, there may be no Subgroup category that clearly describes the observed soil. Thirdly, ponds are drying up and new soils are developing in these environments. How do we classify them? Horizon designations need to be more flexible for these and other soils. The strict separation of a Bv from a Bss horizon is often not possible because they intergrade and mix due to argillipedoturbation. The designations Bvss and Bssv could be used when this occurs. Another example is the Bn and Bnt horizons. The letter k is not used with Bn or Bnt even when calcium carbonate is present. Is the CSSC assumption that calcium carbonate is always present in Solonetzic soils? There are profiles where gypsum is present is some BC Solonetzic soils and calcium carbonate is not. Bnk and Bntk designations would accurately reflect the presence of calcium carbonate. For a more complete description of soil horizons it is suggested that all letters that describe the horizon be permitted. Do we need to develop a new soil order, for example Anthrosolic, to capture reclaimed mine sites and human impacted soils? Currently mine tailings, rock dumps, talus slopes etc. are classified as non soils. Mine tailings are being reclaimed and amended with organic matter, vegetation is being established and horizons are developing. When do reclaimed materials become classified as soils? There is also a conflict between the definitions of soils and non soils. If soils are defined as capable of supporting plant growth how can a non soil talus slope that is forested be classified as a non soil? Soil science students often find the Canadian System of Soil Classification too technical and difficult to use. Suggestions for improving the Canadian System of Soil Classification manual include reexamining the definitions of soils and non soils, allow for horizon designation flexibility, possibly adding a letter for the presence of gypsum, adding more illustrative diagrams, and photographs, simplifying redundant text and adding a chapter that clearly outlines how to use the manual.

Description and classification of two soils within recently dehydrated ponds and one soil bordering a saline pond in the Kamloops Region of British Columbia E.K. WATSON1, JOHN STARCHUK2, SHARON BREWER2 1

Dept of Natural Resource Science, Thompson Rivers University, Kamloops, BC. V2C 5N3 Chemistry, Thompson Rivers University, Box 3010, Kamloops, BC, V2C 5N3 [email protected]

2

Keywords: Solonetzic, Vertic, saline ponds, classification The Canadian System of Soil Classification definition of soils includes soils that develop under up to 60 cm of water. Two soil profiles were established, one in Cattle Pond which was accidentally drained in 2005, and another in Batchelor Lake that dehydrated naturally in 2007. A third profile was established bordering the hydrated saline Long Pond. The profiles were sampled for chemical analysis, described, photographed and classified. Cattle Pond was used as a cattle water source for many years but dried up when a deep dugout, placed at the edge of the pond, broke though the pond clay base, and the water drained into underlying coarse textured materials. The new soil developing in the pond clay substrate appears to fall into the Vertisolic order as gilgi topography; vertic cracks are present along with evidence of argillipedoturbation and juvenile slickenside development. Preliminary classification places this soil in the Vertisolic or Gleysolic order. Batchelor Lake dried up in 2007 for the first time in recent memory. Historical aerial photography was ortho rectified and surface water areas were mapped, using Geographic Information Systems, for 1999, 2003, 2004, 2005 and 2007. There is a linear surface water area decrease from 1999 to 2007. The soil profile was placed within the 2007 dehydrated area. Deep vertic cracked developed along with some evidence of argillipedoturbation. Slickensides were not noted as there have not been any repeated wetting and drying cycles required for them to develop. A thin, organic Ahv layer, overlays Bngv horizon which displays well developed columnar structure. The Cg is coarser textured and is underlain by a marl layer. Preliminary classification places this soil in the Solonetzic order. The Long Pond soil profile was placed in an area dominated by salt grass, D. stricta. This soil did not display any vertic features and falls into the Solonetzic order. However, this area may be periodically covered by water and historical aerial photographs will be examined to determine if this is the case. The chemical and physical analysis for these three soils is being completed and will be presented along with their descriptions and classifications.

Nutrient retention and leaching potential of coarse wood bolts collected from logged and burned upland boreal sites: a greenhouse misting experiment SCOTT A. WIEBE*1, DAVE M. MORRIS2, NANCY J. LUCKAI1 1

Faculty of Forestry and the Forest Environment, Lakehead University, 955 Oliver Road, Thunder Bay, ON CANADA P7B 5E1 2 Ontario Ministry of Natural Resources, Centre for Northern Forest Ecosystem Research, c/o Lakehead University, 955 Oliver Road, Thunder Bay, ON CANADA P7B 5E1 [email protected] Keywords: coarse woody debris, leachate, TOC, TON, base cations The “bio-economy”, increasingly dependant on forest biomass, has been gaining momentum in the last few years in Canada. Subsequently, there is a need to more completely understand the impacts of intensive harvest on forested sites. The purpose of this study was to provide an index of nutrient flux from coarse woody debris (CWD) and address the question: Does either species (aspen, spruce), origin (fire, harvest), and/or age (<1 year, 15 years) influence the timing, rate, and spatial pattern of nutrient release from CWD? Previous studies have not dealt with the pattern of nutrient release from CWD (e.g. simplistic before/after approaches were taken). Therefore, a greenhouse experiment using suspended logs and a misting system was implemented in a greenhouse at Lakehead University in January, 2008. Sixteen weekly collections of leachate were tracked for total run-off volumes and analysed for TON (Nitrogen), TOC (Carbon, P, base cations (Ca, Mg, K, Na) and trace metals (Cu, Fe, Zn, Mn). Repeated measures ANOVA was used to investigate the time effect as well as relationships between the main effects and the measured parameters. ANOVA identified age as a significant source of variation. Higher TON and TOC was associated with older logs (13-73 mg TON and 90-227 mg TOC/week) than younger logs, which acted as a sink/ small source of TON (-0.45 - 0.46 mg/week) and a small source of TOC (16.4 – 73 mg/week). Higher P was associated with younger logs (0.5 – 0.9 mg/week), although older logs were still a small source (0.02 – 0.3 mg/week). Aspen logs produced more P than did spruce but there were no other species effects. Fire origin CWD did not differ from harvested samples, although an origin/species interaction for TOC was noted. Time was not a significant factor in the first six weeks of the repeated measures, although full-term (16 weeks) results could differ. These analyses, as well as multivariate analyses (e.g. non-metric multidimensional scaling), will be repeated when total nutrient flux is calculated upon completion of the project. It is anticipated that final flux data will provide baseline information and supply input to a corresponding field study. In combination with existing data, this will allow for an assessment of the contribution of logging slash to total ecosystem nutrient pools and fluxes.

Development of EdIRT (the Edaphic Indicator Research Tool) as a database for linking relevant environmental information with microbial DNA sequences and other profiles RICHARD S. WINDER1 1

Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, 506 W. Burnside Rd., Victoria, B.C. V8Z 1M5 [email protected] Keywords: software, informatics, microbial ecology, forestry Every gram of forest soil can contain thousands of microbial species, many of which are uncultivable and are only detectable through various molecular and biochemical tests. Public databases provide scant information on the environmental context of microbial isolations, and yet this information is crucial if we are to understand the functional and ecological roles of these complex communities. EdIRT (the Edaphic Indicator Research Tool) can be used to link important environmental information to the molecular and biochemical signals of key indicator microbes. The core of EdIRT is a relational database that links details concerning microbial characterization (genetic sequences, biochemical profiles, etc.), collection data (origin, collector, date, public database accession numbers, etc.), and environmental information (soil type, pH, temperature, understory plants, trees, disturbance, ecozone, etc.) This core is currently populated with a prototype dataset, containing more than a hundred DNA sequences and enzyme profiles corresponding to edaphic microbes. The sequences and profiles pertain to the microbial ‘baseline’ communities found in coastal Douglas-fir forests of Vancouver Island, and correspond to undisturbed forests of varying levels of productivity, and disturbed plots where tree thinning treatments cause both short and long term impacts in the forest soils. The DNA sequences found in the database correspond to specific potential indicators of thinning and productivity, detected with DGGE (denaturing gradient gel electrophoresis). Currently, the database is maintained in two parallel formats: MS Access and MySQL. The Access version allows for easy data entry and flexible queries for data other than genetic sequences, while the MySQL version is opensource. A PHP web-enabled interface has been developed for the MySQL version. The PHP interface supports queries of target gene sequences using a hybrid of the Genbank and Boyer-Moore approaches. General availability of the database is pending several refinements, such as translation into official languages, improving data entry using the PHP interface, and also improving queries available with the PHP interface. Ultimately, soil microbiologists should be able to use EdIRT to link the occurrence of specific microbes to various biotic and abiotic factors occurring in the natural environment.

Land use and riparian effects on prairie wetland sediment properties and herbicide sorption DANI XU*1, SHEILA MEYERS2, JEANETTE GAULTIER3, ANNEMIEKE FARENHORST2, DAN J. PENNOCK1 1

University of Saskatchewan, 51 Campus Drive, Saskatoon, SK University of Manitoba, 362 Ellis Building, Winnipeg MB 3 Manitoba Agriculture, Food and Rural Initiatives, 3rd Avenue NE, Carman, MB [email protected] 2

Keywords: herbicide sorption, sediment, land use, riparian effects Few studies have examined the effects of land use on the physical/chemical properties of wetland sediments and the relationships between these properties and herbicide sorption. We determined the sediment properties for 17 wetlands under five different land use classes: ephemeral wetlands embedded in cultivated field with no riparian vegetation (ECNR), ephemeral wetlands embedded in cultivated field with riparian vegetation (ECR), ephemeral wetlands with four–year grass cover (cultivated prior to 2004) with no riparian vegetation (E4G), ephemeral wetlands with around 20 year brome grass cover with no riparian vegetation (E20G) and semi–permanent spill and fill wetlands with large multi–land use catchment upslope (PC). As well we determined the sorption of trifluralin (2,6– dinitro–N,N–dipropyl–4–trifluoromethylaniline), atrazine (2–chloro–4–(ethylamine)–6– (isopropylamine)–s–triazine), 2,4–D (2,4–dichlorophenocyacetic acid), and glyphosate (N– (phosphonomethyl) glycine) on these sediments. The sorption of 2,4–D, atrazine and trifluralin is highly correlated to total organic carbon (TOC), electrical conductivity (EC), exchangeable cations and total cation exchangeable capacity (CEC). Glyphosate sorption has a weak negative correlation to pH, total inorganic carbon (TIC), exchangeable cations and clay, and the regression model for the sorption of glyphosate is best fitted with pH and clay as variables. The sorption of trifluralin is well described by regression models with TOC and EC as variables. Despite the strong relationship between TOC and herbicide sorption partition coefficient (Kd) of 2,4–D and atrazine, the regression models for sorption of those two herbicides was better described with total CEC and clay. Overall, wetlands under ECNR and E4G land use regime adsorb less herbicide than ECR, E20G and PC wetlands. ECR wetland sediments have the largest capacity for all four herbicides, indicating the potential for those wetlands to become sinks for herbicides in a wetland ecosystem.

Determination of herbicide residues in wetland sediments using LC/MS/MS DANI XU*1, ALLAN J.CESSNA2, RENATA RAINA3, ANNEMIEKE FARENHORST4, DAN J. PENNOCK1 1

University of Saskatchewan, 51 Campus Drive, Saskatoon, SK Environment Canada, 11 Innovation Boulevard, Saskatoon, SK 3 University of Regina, 3737 Wascana Parkway, Regina, SK 4 University of Manitoba, 362 Ellis Building, Winnipeg MB [email protected] 2

Keywords: herbicide residue, sediment, extraction, LC/MS/MS The Prairie Pothole Region (PPR), which encompasses over 777 000 km2 of south central Canada and north central United States, has millions of water–holding depressions of glacial origin (Sloan, 1972). Many of these wetlands are situated amongst agricultural land where herbicides are used on a regular basis for weed management in crop production. Herbicides can enter agricultural wetlands through many routes, such as application drift, wet and dry atmospheric deposition, and wind and water erosion of treated soil (Cessna et al., 1997; Cessna et al., 2001; Larney et al., 1999; Waite et al., 2002). A method was developed to analyze 7 commonly-used sulfonylurea (SU) herbicide residues in wetland sediments. SU herbicides were detected in sediments collected from 17 wetlands in Saskatchewan and Manitoba. Ethametsulfuron-methyl, sulfosulfuron and nicosulfuron were more frequently detected in the sediment than the any other SU herbicides. Sources of SU in the wetland are likely from atmospheric deposition and snowmelt runoff. Reference List Cessna, A., H. Vaughan, D. Munro, and R. Woychuk. 1997. Transport of nutrients and postemergence-applied herbicides in runoff from corrugation irrigation of wheat, In M. Meyer and E. Thurman, eds. Herbicide metabolites in surface and groundwater. American Chemical Society Books. Cessna, A., J. Elliott, L. Tollefson, and W. Nicholaichuk. 2001. Herbicide and nutrient transport from an irrigation district into the south Saskatchewan river. Journal of Environmental Quality 30:1796-1807. Larney, F., A. Cessna, and M. Bullock. 1999. Herbicide transport on wind-eroded sediment. Journal of Environmental Quality 28:1412-1421. Sloan, C. 1972. Ground-water hydrology of Prairie Potholes in North Dakota [Online]. Available by U.S. Geological Survey http://www.lib.ndsu.nodak.edu/govdocs/text/potholes/585c.html. Waite, D., A. Cessna, R. Grover, L. Kerr, and A. Snihura. 2002. Environmental concentrations of agricultural herbicides: 2,4-D and triallate. Journal of Environmental Quality 31:129-144.

Sensitivity analysis of crop management parameters in the Decision Support System for Agrotechnology Transfer (DSSAT) model J.Y. YANG1, C.F. DRURY1, R. DE JONG 2 and G. HOOGENBOOM3 1

Greenhouse & Processing Crops Research Centre, Agriculture and Agri-Food Canada, 2585 County Rd 20, Harrow, ON, Canada, N0R 1G0 2 Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, Canada, K1A 0C6 3 Department of Biological and Agricultural Engineering, The University of Georgia, 165 Gordon Futral Court, Griffin, Georgia 30223-1797, USA [email protected] Keywords: Sensitivity analysis, DSSAT model, plant growth, plant N, soil N The Decision Support System for Agrotechnology Transfer (DSSAT) v4.0 model is guided by the premise that it is more efficient to use models to find alternative ways to improve agro-ecosytem performance than to only experiment with the system itself. A sensitivity analysis of the model was conducted, using 15 crop inputs. Four field crops were tested in this study: soybean (UFGA8101, Florida), corn (IUAF9901, Iowa), wheat (SWSW7501, Saskatoon) and potato (NYCU8001, New York) were simulated using CSM-CROPGRO-Soybean, CSM-CERES-Maize, CSM-CERES-Wheat and CSM-SUBSTOR-Potato, respectively. Model outputs of crop growth, N uptake, and soil N levels were plotted using the EasyGrapher program. For each crop, about 1500 runs were executed; i.e. the effect of 15 input parameters on 100 variables, including plant growth, plant N, soil N and summary variables, were examined. All model runs were ranked by “Y”, “N” and “NA” in the summary tables, where Y represents a sensitive relationship between input and output variables, whereas N was not sensitive and NA not applicable. A total of 12 ranking tables were constructed. Sensitivity trends for each of the key input parameters will be discussed. For all crops, six of the input parameters had a significant influence on the model output. The most sensitive parameters were planting date, population density, planting depth, fertilizer N application rate, date and source. Planting date: A delay in planting date by 7~10 days resulted in yield reductions for soybean, corn and wheat by 8~12, 8~28, and 4~8 % and a delay by 25 days resulted in yield reductions 28%, 40% and 13%, respectively. For potato, an indeterminate species, a later planting date led to a delay in reaching maximum biomass and hence, a delay in maturity of the potato tubers. Population density: yields increased linearly with increasing population density when it was in the low to mid range, but the yields levelled off when the population density reached an optimal level. Fertilizer N rate: fertilizer N rate followed a diminishing yield and N uptake pattern for maize, potato and wheat, indicating that the maximum yield and N uptake can be obtained from a fertilizer N response curve. Soybean yield did not respond to different levels of fertilizer N rates, because it is a leguminous crop which fixes N2 from the atmosphere. Total N uptake by soybean increased greatly with increased fertilizer N rates which are indicative of luxurious N consumption. With the increases of fertilizer N rates, all crops showed that soil mineral N level increased accordingly, which could enhance both N leaching and N denitrification. Model outputs did not show a response to changes in harvesting dates for soybean, corn and wheat, but potato tuber yields were reduced by 18% if harvested 15 days earlier. The crops were not sensitive to the amount of crop residue present.

Organic carbon content in particle size fractions of a Brookston clay loam soil under no-tillage and mouldboard plough management XUEMING YANG1, CRAIG F. DRURY1, W. DANIEL REYNOLDS1, JINGYI YANG1 1

Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, Ontario, Canada N0R 1G0 [email protected]

Keywords: soil particles, soil organic carbon (SOC), tillage No-tillage (NT) often increases total soil organic carbon (SOC) stocks relative to mouldboard ploughing (MP). We have found, however, that NT and MP produce similar total SOC stocks within the top 20 cm of a Brookston clay loam in Southwest Ontario, although NT accumulates more SOC near the surface and less SOC at depth, while MP has a generally uniform SOC distribution. Since soil particles have a major effect on the physical and chemical characteristics of soil, we hypothesized that SOC associated with different particle sizes (sand, silt, clay) may vary between NT and MP soil. The objective of this study was to assess SOC content in the sand (0.053 - 2 mm), silt (0.002 - 0.053 mm) and clay (≤0.002 mm) size fractions of the Brookston clay loam soil under NT and MP. Soil cores were collected in early May 2007 from a tillage study which was initiated in 1996 by splitting existing (13-y) MP and NT plots in half. One half of the 13-y MP plot was converted into new-NT (N-NT) while the remaining half was left intact as long-term MP (L-MP). Similarly, one half of the 13-y NT plot was converted to new-MP (N-MP) while the remaining half was left intact as long-term NT (LNT). Each soil core was cut into 0-5, 5-10, 10-20, 20-30 and 30-40 cm depth segments. The segments were air-dried and ground to <2 mm and then dispersed into discrete particles by applying ultrasound energy at 750 J mL-1 to a 1:4 soil:water suspension. Sand, silt, and clay size fractions were collected and the SOC contents in the fractions measured. For all three size fractions, L-NT led to significantly higher SOC concentrations in the top 5 cm compared to L-MP. For the 10-20 cm depth, higher SOC concentration in the clay fraction remained in L-NT relative to L-MP; however, L-NT had significantly lower SOC in sand and silt fractions compared with L-MP. Ten year after splitting the plots, the N-MP resulted in similar SOC concentrations in sand and silt fractions relative to L-MP; however, the SOC in the clay fraction remained higher in N-MP than in L-MP. Relative to L-NT, 10-y N-MP led to significant redistribution of SOC amongst the particle size fractions in the plough layer but no changes in the total SOC stocks. New NT had significantly more SOC in the silt fraction in the depth range between 5 and 30 cm and less SOC in the clay fraction at 20-40 cm relative to L-NT. Meanwhile, the SOC concentrations in the sand fraction were the same for both NT soils. Relative to L-MP, N-MP showed similar SOC concentrations in the sand and silt fractions at all depths. In the top 20 cm, more SOC existed in the clay fractions of NMP than LMP. These results suggest that NT and MP can cause differences in SOC composition amongst particle size fractions.

Carbon accumulation and microbial activity in deep peat soils JOSEPH B. YAVITT1, CHRISTOPHER J. WILLIAMS2 1

Department of Natural Resources, Cornell University, Ithaca, NY 14853-3001 USA Department of Earth & Environment, Franklin & Marshall College, Lancaster, PA 17603 USA [email protected]

2

Keywords: carbon dioxide, decomposition, organic soil, peatland The goal of this research is to better understand the accumulation and maintenance of carbon in temperate peatlands by studying the trajectory of past soil carbon accumulation as well as rates of microbial activity in peat soils. The retreat of the Laurentide ice sheet from the northeastern United States created an environment conducive to peat accumulation in newly formed wetlands and resulted in a new terrestrial sink for atmospheric carbon dioxide. To understand the processes that regulate post-glacial carbon accumulation we studied deep (> 6 m) peatlands located between 41° and 44°N latitude that initiated peat formation between 14 and 9.4 ka BP. Botanical development followed a general sequence of lake infilling to fen or bog deposits across all of the sites we studied. Peat formation rate varied between sites and through time. Two of the deposits we studied experiencing brief periods (<1 ka) of rapid peat accumulation (0.2 to 0.6 cm per century) whereas a third site accumulated peat at a relatively uniform rate. Surprisingly, peat accumulation rate was not correlated with the degree of peat decomposition (measured as pyrophosphate index). In all of the peat deposits we studied, the correlation between the degree of decomposition and depth was low and not statistically significant (e.g., Spearman ρ = 0.133, 0.124) whereas in a third site decomposition actually declined with increasing age of the peat (Spearman ρ = 0.556). Within a deposit, the degree of peat decomposition correlated with the peat botanical origin. The abundance of arborescent or shrubby vegetation remains was significantly positively correlated with degree of decomposition (e.g., Spearman ρ = 0.599) and significantly negatively correlated (Spearman ρ = -0.513) with the abundance of bryophyte remains.

Carbon mineralization in particle size fractions of a Brookston clay loam soil under no-tillage and mouldboard plough management ZHIDAN ZHANG*1, 2, XUEMING YANG1, CRAIG F. DRURY1, W. DANIEL REYNOLDS1, LANPO ZHAO2 1

Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, Ontario, Canada N0R 1G0 Dept. of Natural Resource & Environ. Science., Jilin Agricultural University, Changchun, China 130118 [email protected] 2

Keywords: soil size fractions, soil organic carbon (SOC), mineralization, tillage The organo-mineral fractions of specific particle sizes often play a significantly different role in the composition and turnover rate soil organic carbon (SOC). However, no data are available on the contents of SOC in organo-mineral particle-size fractions and its turnover rates for heavy textured soils under different tillage management in Southwest Ontario. Hence, the objectives of this study were to: 1) determine the contents of SOC associated with the sand (53 - 2000 μm), silt (2 - 53 μm) and clay (<2 μm) size fractions of a Brookston clay loam soil under no-till (NT) and mouldboard plough (MP); and 2) measure SOC mineralization within the sand, silt and clay fractions. Soil samples (0-10 cm) were collected in early November 2007 from a tillage study which was initiated in 1996 by splitting existing (13-y) MP and NT plots in half. One half of 13-y MP plot was converted into newNT (N-NT) while the remaining half was left intact as long-term MP (L-MP). Similarly, one half of 13-y NT plot was converted to new-MP (N-MP) while the remaining half was left intact as long-term NT (L-NT). Bulk soil was dispersed into sand, silt and clay fractions by applying ultrasound energy at 750 J ml-1 to a 1:4 soil:water suspensions. The SOC content of the particle size fractions was determined and the size fractions were aerobically incubated at 20 °C and 30% moisture (w/w) for 29 days. The C-CO2 emissions from the samples were measured at day 1, 2, 5, 9, 14, 20 and 29. We found that more SOC was associated with clay than with silt and sand in all tillage treatments. There was more SOC associated with clay (34.2 g C kg-1) and silt (24.1 g C kg-1) under NT than with clay (28.8 C g kg-1) and silt (20.9 g C kg-1) under MP. Similarly, significantly (P < 0.05) more SOC was associated with the sand fraction under NT (7.1 g C kg-1) than under MP (3.7 g C kg-1). For all tillage treatments, carbon mineralization decreased with time. Both No-till soils showed significantly higher mineralization rates than two MP soils. The clay size particles emitted significantly greater CO2 relative to the silt and sand fractions. Hence NT produced more SOC in all three particle size fractions relative to MP in the top 10 cm, and that SOC associated with the silt and clay fractions was more labile under NT than under MP.

Characterization of soil compaction and tree growth in BC forests by relative bulk density YIHAI ZHAO*1, MAJA KRZIC1, CHUCK E. BULMER2, MARGARET G. SCHMIDT3, SUZANNE W. SIMARD1 1

Faculty of Forestry, Univ. of British Columbia, Vancouver, BC V6T 1Z4 Canada British Columbia Ministry of Forests and Range, Research Branch, Vernon, BC V1B 2C7 Canada 3 Dep. of Geography, Simon Fraser Univ., Burnaby, BC V5A 1S6 Canada [email protected] 2

Keywords: maximum bulk density, soil physical properties, soil chemical properties, forest soil Forest management practices often result in soil disturbance and compaction, which in turn strongly affect ecosystem stability and site productivity. Bulk density (BD) is traditionally used to measure soil’s compaction state, but BD is strongly influenced by texture, organic matter content, and other soil properties. Consequently, it has been difficult to determine thresholds for ecosystems that are at risk based on bulk density measurements alone. On the other hand, relative bulk density (RBD, field BD/reference BD) is independent of soil texture and organic matter content, and RBD has been suggested (Carter 1990; Hakansson and Lepiec 2000) as a useful integrate index of soil compaction and crop growth, yet its usefulness has not been proven for forest soils and tree growth.

The objective of this study was to evaluate thresholds for RBD in relation to tree growth. A total of 283 bulk density soil samples were collected from eight forest sites throughout the Interior of British Columbia (BC), and liquid and plastic limits, particle density, oxidisable organic matter, total carbon, particle size distribution, and Fe, Al oxides were analyzed. The reference bulk density (i.e., maximum bulk density – MBD, determined by the standard Proctor test) values were predicted based on the relationship between MBD and these soil physical and chemical properties (Zhao et al. 2008), and RBD values were determined accordingly. Tree height growth at these eight sites was measured from 2000 to 2007, and the relationship between tree height growth and soil RBD was assessed.

Relationships found in this study have implications in the assessment of forest soil compaction status and its effect on site productivity. The results will also help predict and monitor soil behaviour and associated tree performance in response to timber harvesting and site restoration. Reference List Carter, M.R., 1990. Relative measures of soil bulk density to characterize compaction in tillage studies on fine sandy loams. Can. J. Soil Sci. 70:425-433. Hakansson, I. and Lipiec, J., 2000. A review of the usefulness of relative bulk density values in studies of soil structure and compaction. Soil Tillage Res. 53:71-85. Zhao, Y., Krzic, M., Bulmer, C.E., and Schmidt, M.G. 2008. Maximum bulk density of British Columbia forest soils from the Proctor test: relationships with selected physical and chemical properties. Soil Sci. Soc. Am. J. 72: 442–452.

Soil response to drilling mud application to a semiarid native prairie FRANCIS ZVOMUYA1, FRANK J. LARNEY1, ANDREW F. OLSON1, PAUL R. DEMAERE1, DAN YAGOS1 1

Agriculture and Agri-Food Canada, 5403 1st Ave. S., Lethbridge, AB, Canada T1J 4B1 [email protected] Keywords: water-based muds, petroleum industry waste, soil chemical-physical properties

Drilling fluids or muds are used by the petroleum industry during the drilling of oil and natural gas wells to lubricate and cool the drill bit, and to control subsurface wellbore pressure. They also function to remove drilled-out rock cuttings from the well, clean the bit and the bottom of the hole, and stabilize the wellbore. In western Canada, non-toxic, spent water-based muds (WBM) are often applied to cropland and sometimes native prairie at low application rates as a disposal option. There is concern, however, that application of drilling waste on native prairie in semi-arid climates may alter soil chemical and physical properties as well as plant growth and species composition, which in turn may adversely affect overall ecosystem productivity. This study was initiated to examine the effects of spent WBM on vegetation and soil properties. In this poster, we address the relationships between differential rates (0, 15, 20, 40 and 80 m3 ha-1) of single or multiple summer vs. fall applications of drilling mud and key soil chemical and physical properties at various stages during the 4-yr study.