Naeth, M. A., Archibald, H. A., Nemirsky, C. L., Leskiw, L. A., Brierley, J. A., Bock, M. D., VandenBygaart, A. J. and Chanasyk, D. S. 2012. Proposed classification for human modified soils in Canada: Anthroposolic order. Can. J. Soil Sci. 92: 7-18. With increasing anthropogenic activity, the areal extent of disturbed soils is becoming larger and disturbances more intense. Regulatory frameworks must incorporate reclamation criteria for these disturbed soils, requiring consistent descriptions and interpretations. Many human altered soils cannot be classified using the Canadian System of Soil Classification (CSSC), thus an Anthroposolic Order is proposed. Anthroposols are azonal soils, highly modified or constructed by human activity, with one or more natural horizons removed, removed and replaced, added to, or significantly modified. Defining features are severe disruption of soil forming factors and introduction of potentially new pedogenic trajectories. Disturbed layers are anthropic in origin and contain materials significantly modified physically and/or chemically by human activities. Three great groups are defined by presence of anthropogenic artefacts and organic carbon content. Six subgroups are based on a cover soil layer with higher organic carbon content than the profile below it, on depth of disturbance, on drainage characteristics and water regime at the site. Some new phases and modifiers, in addition to traditional ones used in the CSSC, are based on chemical and physical properties and origins of anthropogenic artefacts. The proposed classification has been successfully applied to reclaimed profiles and is ready for widespread field testing.

Larney, F. J. and Angers, D. A. 2012. The role of organic amendments in soil reclamation: A review. Can. J. Soil Sci. 92: 19-38. A basic tenet of sustainable soil management is that current human activities are not detrimental to future generations. Soils are degraded by natural events (erosion) or industrial activity. A prevalent feature of degraded or disturbed soils is lack of organic matter compared with adjacent undisturbed areas. Organic amendments, such as livestock manure, biosolids, pulp and paper mill by-products, wood residuals and crop residues, are produced in abundance in Canada and could be widely used in soil reclamation. Biosolids production is ~0.5 Tg yr^-1(dry wt.); paper mill sludge generated in the province of Quebec was ~2 Tg (wet wt.) in 2002. This review paper examines mechanisms through which organic amendments affect soil properties (physical, chemical, biological) and describes the role of organic amendments in reclamation, with emphasis on amendment types and application rates for soil amelioration and biomass production. Single large applications of organic amendments can accelerate initial reclamation and lead to self-sustaining net primary productivity. Readily decomposable organic amendments may provide immediate, but transient, effects, whereas stable, less decomposable materials may provide longer-lasting effects. Using organic amendments for reclamation is mutually beneficial wherein waste products from agriculture, forestry and urban areas help other sectors meet their land reclamation goals.

Powter, C. B., Chymko, N. R., Dinwoodie, G., Howat, D., Janz, A., Puhlmann, R., Richens, T., Watson, D., Sinton, H., Ball, J. K., Etmanski, A., Patterson, D. B., Brocke, L. K. and Dyer, R. 2012. Regulatory history of Alberta's industrial land conservation and reclamation program. Can. J. Soil Sci. 92: 39-51. Alberta first legislated the requirement to reclaim land disturbed by industrial activities in 1963 with the enactment of the Surface Reclamation Act. In 1973 the Land Surface Conservation and Reclamation Act introduced the concept of conservation and added new regulated industries and an approvals process. In 1993 the Environmental Protection and Enhancement Act linked reclamation and remediation in a single Act. Alberta's industrial land conservation and reclamation program developed over 48 yr from an initial focus on surface debris removal and safety to increasing emphasis on returning ecological function and minimizing cumulative effects. The program has been influenced by various factors, includingregulatory policies and objectives, education and expectations of stakeholders and the public, educational background and expertise of regulators, advances in science, technology and industry practices, type and scale of land disturbances, intended post-reclamation land use, and working with partners. Vigorous discussion and debates on productivity vs. capability, reclamation vs. restoration, reclamation vs. remediation, conservation vs. reclamation, land vs. water and scientific possibilities vs. practical realities have shaped the program's direction. This review will provide insights for other jurisdictions dealing with the need to balance industrial development and environmental protection in the face of growing public awareness and scrutiny.

Krümmelbein, J., Bens, O., Raab, T. and Naeth, M. A. 2012. A history of lignite coal mining and reclamation practices in Lusatia, eastern Germany. Can. J. Soil Sci. 92: 53-66. Germany is the world's leading lignite coal producer. The region surrounding the towns of Cottbus and Senftenberg in Lusatia, Eastern Germany, is one of the largest mining areas in Germany, and has economically been strongly dependent on lignite mining and lignite processing industries since the middle of the 19th century. We introduce the area, give a brief historical overview of lignite mining techniques and concentrate on post-mining recultivation (reclamation) to agricultural and forestry dominated landscapes. An overview of the physical and chemical limitations for reclamation of the Tertiary and Quaternary substrates due to their natural composition and the technical processes of mine site construction is provided. We introduce some recultivation practices and end with a display of land uses before and after mining and an outlook on the future use of the reclaimed landscape. This review serves as a defined perspective on long-term coal mine reclamation from which to address global similarities and contrasts.

Boldt, K., Schneider, B. U., Fritsch, S. and Hüttl, R. F. 2012. Influence of root growth of two pioneering plant species on soil development during the initial stage of ecosystem genesis in the Lusatian post mining landscape. Can. J. Soil Sci. 92: 67-76. To characterize the role of root growth of Lotus corniculatus L. (bird's-foot trefoil) and Calamagrostis epigeios L. Roth (chee reed grass) in soil development during the initial stage of ecosystem genesis, the root systems of these plant species growing in soils from quaternary calcareous sediments were studied. The spatial distribution pattern of root systems varied considerably. Both plant species contributed to the accumulation of organic carbon in the bulk soil, although the highest concentrations were from the legume L.corniculatus. Total nitrogen concentration in the bulk soil was not affected, but increased in the rhizosphere soil of both plant species. There were clear indications that both plant species contributed to homogenizing phosphorus distribution, resulting in phosphorus depletion of those soil compartments where root proliferation was highest. Pronounced differences were detected between plant species, which led to the conclusion that the homogenizing effect caused by one species on a plot level may be overridden by the heterogeneity of patches composed of different plant species at the ecosystem level. All considered components suggest that the development of root systems of herbaceous pioneer plant species provides significant contributions to land reclamation in a natural way.

Drozdowski, B. L., Naeth, M. A. and Wilkinson, S. R. 2012. Evaluation of substrate and amendment materials for soil reclamation at a diamond mine in the Northwest Territories, Canada. Can. J. Soil Sci. 92: 77-88. Mine waste materials with potential for use in soil construction at a diamond mine in the Northwest Territories were evaluated to address physical and chemical limitations for plant establishment, growth and development. Substrates were glacial till, gravel, processed kimberlite, and 50:50 and 25:75 mixes of processed kimberlite and till. Amendments were salvaged topsoil, sewage sludge, inorganic fertilizer and sludge from a water treatment facility. Reclamation soils constructed with these materials were adequate for revegetation. Mixes of processed kimberlite and glacial till enhanced soil structure and diluted adverse concentrations of elements. The original gravel pad, alone or amended, was a suitable substrate for plants. Addition of organic amendments topsoil and sludge, to any substrate, increased organic matter, nutrients and surface water retention. Of amendments evaluated, salvaged topsoil provided the most consistent increase in plant density among substrates. Inorganic fertilizer applied to gravel or till provided results similar to those with topsoil. Sludge had potential to amend mixes of processed kimberlite and till, although results were variable. Sewage was a good source of organic matter, increasing soil water content and macro nutrients. Vegetation response was poor in sewage-amended treatments likely due to combined effects of high copper, molybdenum, phosphorus, selenium, sulphate and zinc.

Gardner, W. C., Naeth, M. A., Broersma, K., Chanasyk, D. S. and Jobson, A. M. 2012. Influence of biosolids and fertilizer amendments on element concentrations and revegetation of copper mine tailings. Can. J. Soil Sci. 92: 89-102. A 3-yr field study on copper mine tailings in British Columbia determined the effects of fertilizer and biosolids on element concentrations in tailings and vegetation and on plant biomass. Biosolids applied at 50, 100, 150, 200 and 250 Mg ha^-1 (dry weight) increased total carbon, iron, magnesium, nickel, nitrogen, phosphorus, sulphur and zinc and available ammonium, iron, manganese, nitrate, phosphorus and zinc in tailings. With highest applications on silt loam tailings, total zinc (214 mg kg^-1) exceeded Canadian Council of Ministers of the Environment guidelines for agricultural soils. Total chromium and copper exceeded these guidelines but not due to biosolids, being high in controls (chromium 38, 8; copper 647, 1291 mg kg^-1; silt loam and sandy sites, respectively). Plant tissue calcium, phosphorus, magnesium, manganese, nitrogen and zinc increased with increasing biosolids. Plant tissue calcium (20 g kg^-1) and molybdenum (5 mg kg^-1) exceeded National Research Council maximums for beef cattle. Total molybdenum in unamended silt loam (35 mg kg^-1) and sandy tailings (18 mg kg^-1) and vegetation on silt loam (112 mg kg^-1) were high. Biosolids had variable effects on tailings molybdenum and decreased total plant tissue molybdenum. Fertilizer and control treatments had limited plant growth. Managed biosolids use in reclamation can ameliorate sites and facilitate vegetation establishment, with low environmental risk.

Carrera-Hernández, J. J., Mendoza, C. A., Devito, K. J., Petrone, R. M. and Smerdon, B. D. 2012. Reclamation for aspen revegetation in the Athabasca oil sands: Understanding soil water dynamics through unsaturated flow modelling. Can. J. Soil Sci. 92: 103-116. Reclamation of mined areas in the Athabasca oil sands region is required by law, with the ultimate goal of revegetating to species characteristic of predisturbance native plant communities. To develop adequate reclamation strategies, an analysis of soil water dynamics is of utmost importance, as is understanding the impact of the thickness of the reclamation cover. In this work, soil water dynamics and fluxes at the water table were simulated for three reclamation scenarios and compared with the fluxes obtained for natural conditions assuming that aspen is the target reclamation species. According to the simulations, a reclamation thickness between 0.5 and 1.0 m can be used to provide water for revegetation. The numerical simulations show that the reclaimed landscapes have fluxes at the water table that exhibit less fluctuation than natural conditions. To limit the interaction between the water table and atmospheric fluxes, and to limit upward flux, the water table should be deeper than 2.0 m on reclaimed landscapes that use aspen for revegetation, particularly when reclamation takes place during a dry climatological cycle.

Leatherdale, J., Chanasyk, D. S. and Quideau, S. 2012. Soil water regimes of reclaimed upland slopes in the oil sands region of Alberta. Can. J. Soil Sci. 92: 117-129. Large oil sands deposits in the Athabasca oil sands region of Alberta, Canada, are recovered through surface mining, creating a large-scale disturbance. Reclamation requires reconstruction of soil profiles to return the land to equivalent land capability and support the required end land use. Soil water regimes must be understood to allow for planting of appropriate vegetation species. This study quantified soil water regimes on reclaimed upland slopes of various reclamation prescriptions and determined whether soil water was affected by slope position. Slope position did not have a consistent effect on soil water. Spatial variability in soil characteristics and vegetation distribution likely had a greater influence on soil water than did slope position. The upper slope soil profiles had highly dynamic water regimes and a greater response to precipitation events than the lower soil profiles. Differences in water-holding capacity among sites were attributed to differences in clay, sand and organic matter content. Overwinter soil water recharge varied dramatically by site. Capillary barriers resulting from the textural discontinuities created by the reclamation prescriptions enhanced soil water retention within the profiles in at least two sites, and hence are desirable in reclamation scenarios, especially where reclamation material is coarse textured.

MacKenzie, M. D. and Quideau, S. A. 2012. Laboratory-based nitrogen mineralization and biogeochemistry of two soils used in oil sands reclamation. Can. J. Soil Sci. 92: 131-142. In the Athabasca oil sands region of Alberta, Canada, peat mineral and upland forest floor mineral soils are salvaged and stockpiled for reclamation. Previous work showed that sites reclaimed with forest floor mineral soil had better understory regeneration and nitrogen dynamics more similar to naturally disturbed ecosystems. Both soils and a mixture of the two were compared in laboratory incubations by examining nitrogen mineralization (over 45 wk) and factorial fertility additions (4 wk trial with NPK) on microbial community structure and nutrient availability. Nitrogen mineralization indicated forest floor mineral soil had lower release rates and a higher estimated labile nitrogen pool than peat mineral soil. Nitrogen mineralization in mixed soil started like peat mineral soil and finished like forest floor mineral soil. Fertility additions influenced microbial community structure less than soil type. Multi-response permutation procedure indicated the forest floor mineral soil microbial community was significantly different from peat mineral and mixed soil communities. Control nutrient profiles differed from those with added NPK. Forest floor mineral soil retained nitrogen as ammonium, while peat mineral and mixed soils were nitrate dominated. Reclamation will require all soil types to be used and these data will help determine soil placement prescriptions.

Pinno, B. D., Landhäusser, S. M., MacKenzie, M. D., Quideau, S. A. and Chow, P. S. 2012. Trembling aspen seedling establishment, growth and response to fertilization on contrasting soils used in oil sands reclamation. Can. J. Soil Sci. 92: 143-151. Trembling aspen (Populus tremuloides) is an important tree species for land reclamation. This study determined trembling aspen germination, establishment, initial growth and response to fertilizer on contrasting oil sands reclamation soils. In a greenhouse, eight soils varying in total nitrogen and available phosphorus were treated with no fertilizer (control), phosphorus and potassium (PK), nitrogen (N) and all three (NPK). Soil had the greatest impact on aspen growth when no fertilizer was applied with the best growth occurring on organic-mineral material soils where growth was positively correlated with extractable and foliar potassium but not to nitrogen or phosphorus. With PK and N fertilizer, growth increases were positively correlated with foliar phosphorus concentrations of the corresponding controls. NPK fertilizer caused greater growth, bud set and root:leaf mass ratio compared with PK or N fertilizer. Soil type had little impact on germination and establishment, indicating natural aspen seedlings can potentially regenerate on all of these soils. In oil sands mining reclamation where these soils are used as surface materials, organic-mineral mixes had the greatest potential without fertilizer. With fertilizer, NPK provided maximum growth and developmental benefits.

Turcotte, I. and Quideau, S. A. 2012. Phenolic profiles in natural and reconstructed soils from the oil sands region of Alberta. Can. J. Soil Sci. 92: 153-164. This research was conducted in the Athabasca oil sands reclamation area of northeastern Alberta, where land reclamation entails reconstruction of soil-like profiles using salvaged materials such as peat and mining by-products. Successful reclamation is in part dependent on the quality of the organic capping of these reconstructed soils. This study investigated organic matter composition between reconstructed and natural soils. Soil samples (0-10 cm) were taken from 45 plots to represent a range of reclaimed and undisturbed sites. The botanical origin of soil organic matter was characterised through cupric oxide oxidation, which yields lignin monomers hypothesized to reflect vegetation inputs and extent of decomposition based on time since reclamation. Additional soil organic matter parameters were obtained using acid hydrolysis, physical separation and ramped cross polarisation C-13 nuclear magnetic resonance techniques. Yields of vanillyl phenols, coumaryl phenols, p-hydroxy phenols, summed lignin phenols and total phenolic constituents were significantly higher in natural soils than in reconstructed soils. We suggest that there may be an accelerated decomposition of peat phenols in reconstructed soils, which would leave only those phenols representative of the vascular plant history accumulated in the initial peat profile.

McConkey, T., Bulmer, C. and Sanborn, P. 2012. Effectiveness of five soil reclamation and reforestation techniques on oil and gas well sites in northeastern British Columbia. Can. J. Soil Sci. 92: 165-177. Techniques developed for forestry landing reclamation were applied to five oil and gas well sites in northeastern British Columbia to ameliorate soil and facilitate reforestation. Treatments implemented in fall 2003 and spring 2004 were tillage, wood chip mulch, tillage wood chip mulch, tillage incorporated wood chips, brush mats and a control. Lodgepole pine (Pinus contorta var. latifolia) and white spruce (Picea glauca) seedlings were planted. Soil and vegetation were assessed (bulk density, soil mechanical resistance, water content, air filled porosity, water retention, least limiting water range, nutrient availability, seedling survival and growth) throughout 2004 and 2005 growing seasons. Tillage improved soil physical condition, reducing soil mechanical resistance and bulk density; treatments did not affect soil chemical properties. Treatments did not significantly affect species survival; after 6 yr, spruce height and root collar diameter improved with tillage but treatments did not affect pine. Brush mats led to increased spruce growth. Regression relationships between tree performance and soil condition were significant, but generally did not explain large variability. More elaborate soil physical condition measures were no better than bulk density for predicting seedling performance, but relative bulk density and least limiting water range may be useful for evaluating soil productivity.

Leskiw, L. A., Sedor, R. B., Welsh, C. M. and Zeleke, T. B. 2012. Soil and vegetation recovery after a well blowout and salt water release in northeastern British Columbia. Can. J. Soil Sci. 92: 179-190. The impact of brine release on soil and vegetation due to a gas well blowout in December 1999 near Fort Nelson, British Columbia was evaluated over a 10 year period. The objectives were to study spatial and temporal distribution of soil salinity and vegetation and determine whether reclamation would occur through a natural recovery process. Soil salinity and vegetation diversity indices were measured on six study sites and one control. Average electrical conductivity declined with time from approximately 3.0 dS m^-1 and has remained below 2.0 dS m^-1 since 2002. Cycling of ions between leaf litter and plant tissue resulted in high variability in topsoil electrical conductivity. Sodium adsorption ratio in the leaf litter and A horizons was low (<7), but remained high in B and C horizons (>14) after 2004. From 2002 to 2010 moss cover increased 40%, whereas shrubs decreased 30%. The most impacted plot showed higher diversity than the least impacted plots and the control (Shannon diversity index = 1.49, 1.36, 1.11 for most impacted, least impacted and control, respectively). Soil and vegetation indicated salt-affected plots were recovering naturally. Results from this study could potentially provide guidelines for future remediation and reclamation practices.

Iverson, M. A., Holmes, E. P. and Bomke, A. A. 2012. Development and use of rapid reconnaissance soil inventories for reclamation of urban brownfields: A Vancouver, British Columbia case study. Can. J. Soil Sci. 92: 191-201. As a result of suburban growth and abandonment and relocation of industrial facilities, vacant lots are becoming common in most urban centers in North America. These neglected, derelict, and often contaminated brownfields are receiving attention as a public liability since they are not productive and detract from the environmental quality of urban centres. Soils at these urban sites have been negatively impacted by anthropogenic activities. A prerequisite to effective reclamation is knowledge about the soil conditions on these sites. Most urban areas do not have soil survey or soil inventory information. Soil physical factors such as compaction are common problems at sites and are difficult and expensive to modify. A soil inventory provides the initial information for remediation and reclamation strategies that incorporate inherent soil properties. A soil inventory was conducted in Vancouver, British Columbia, by interpreting and extrapolating surficial geologic and regional soil survey information. The resulting soil inventory is presented as a series of topographical cross sections through the city, and displays information to stakeholders by reference to cultural features including street addresses. The soil inventory is compiled into soil management groups for general descriptions of the soil units and for initial recommendation for reclamation strategies.

Hargreaves, J., Lock, A., Beckett, P., Spiers, G. A., Tisch, B, Lanteigne, L., Posadowski, T. and Soenens, M. 2012. Suitability of an organic residual cover on tailings for bioenergy crop production: A preliminary assessment. Can. J. Soil Sci. 92: 203-211. To test the potential for production of bioenergy crops, such as canola and corn, an organic cover was constructed over acid-producing mine tailings containing nickel and copper, belonging to Vale in Sudbury, Ontario, Canada. The 1 m deep cover was of organic residuals (biosolids) obtained from a regional paper mill. Corn and canola crops were successfully grown using agricultural techniques. Crop yields from each of 2 yr from the tailings site were greater than those obtained at an agricultural site in the region. Root, shoot and grain analyses indicated low potential for bioaccumulation of potentially hazardous metals from the organic residual cover or the underlying tailings. Over the short term, there was no evidence of metal movement into the biosolids cover or uptake by the crops from the underlying tailing deposits. Importantly, canola seeds and corn kernels, the feedstocks for biodiesel and ethanol biofuels production, did not accumulate environmentally sensitive metals. This preliminary study demonstrates that the placement of an organic residuals cover on mine tailings to support growth of bioenergy crops is a potential novel reclamation strategy for the mining and smelting industry, or for industrial brownfields in general.

Lilles, E. B., Purdy, B. G., Macdonald, S. E. and Chang, S. X. 2012. Growth of aspen and white spruce on naturally saline sites in northern Alberta: Implications for development of boreal forest vegetation on reclaimed saline soils. Can. J. Soil Sci. 92: 213-227. We examined height and basal area growth over time for trembling aspen and white spruce in plots along a salinity gradient at six naturally saline sites in northern Alberta, as a benchmark for forest productivity on reclaimed saline sites. We measured root distributions and analyzed foliage for ions, nutrients and carbon and nitrogen stable isotope ratios. Both species grew on soil conditions previously considered unsuitable for forest vegetation [pH>8.5; electrical conductivity>10 dS m^-1, sodium adsorption ratio>13 at depth (50-100 cm)] yet there was little evidence of nutritional toxicities or deficiencies. Aspen basal area growth decreased 50% as salinity increased, but aspen was commercially productive (site index=22) on soils with electrical conductivity of 7.8 dS m^-1 at 50-100 cm depth. Growth of white spruce seemed to be unaffected by salinity level differences, but 78% of white spruce site indexes were less than 13 and would be considered non-productive. Both species showed growth declines over time, compared with non-saline reference growth curves, and rooted primarily in the forest floor and top 20 cm of soil. This suggests that rooting limitations may constrain longer-term productivity of forests established on sites with salinity at depth.

Holmes, E. P., Wilson, J., Schreier, H. and Lavkulich, L. M. 2012. Processes affecting surface and chemical properties of chrysotile: Implications for reclamation of asbestos in the natural environment. Can. J. Soil Sci. 92: 229-242. A landslide at the headwaters of the Sumas River in southwestern British Columbia, is a seasonal and episodic source of chrysotile asbestos to the floodplain soil. Fresh alluvial deposits of fibres have potential for aeolian movement, posing a health risk to the Sumas watershed population. To understand the effects aquatic and pedogenic processes have on the fibres, asbestos materials from the river and floodplain were subjected to organic acid treatments in the laboratory. Changes were monitored by X-ray diffraction, scanning electron microscopy and elemental analysis. Fibre surfaces modified by organic acid treatments were similar to those affected by natural processes in that they showed a high loss of elements from the brucite layer compared with the silica tetrahedral layer, and the surfaces became smoother due to the loss of a rough amorphous coating. To initiate sustainable reclamation practices, changes in fibre surfaces by natural processes need to be considered and enhanced by incorporation of organic amendments that produce complexing soil acids. Reclamation activities should focus on recently deposited sediment along the floodplain. Non-polluting organic material, such as peat, compost and sawdust could be applied to increase reaction potential and kinetics of the reaction of chrysotile with naturally occurring acids.

Arocena, J. M., van Mourik, J. M. and Faz Cano, A. 2012. Granular soil structure indicates reclamation of degraded to productive soils: A case study in southeast Spain. Can. J. Soil Sci. 92: 243-251. Accelerated conversion of degraded landscapes in mining areas to productive ecosystems requires stimulation of soil formation. The evolution in microstructure and changes to chemical properties in metal mine wastes 5 yr after amendments with pig manure, sewage sludge and marble waste is reported. Mine wastes had <1% organic carbon, <0.05% total nitrogen, pH~2.0, electrical conductivity up to 20 dS m^-1 and high concentrations of metals such as 22000 mg zinc kg^-1 and 7000 mg lead kg^-1. After 5 yr, one time amendment increased total carbon (g kg^-1) from 1.4 (control) to 5.6 (marble waste sewage sludge) to 8.3 (marble waste pig manure). Soil pH in amended plots was 6.0 compared with 2.8 in controls. Micromorphological characteristics clearly showed that primary and secondary calcite serve as active sorption sites for organic matter. These calcitic zones were areas conducive to root growth. Soil microstructure in amended mine wastes was dominantly granular, resulting from activities of soil organisms such as fungi and enchytraeds. Results suggest organic matter can be effectively enriched in mine waste deposits through simultaneous additions of pig manure, sewage sludge and calcite. Soil amendments promoting formation of granular structure can accelerate establishment of productive landscapes in degraded mine sites.

Abedin, J., Beckett, P. and Spiers, G. 2012. An evaluation of extractants for assessment of metal phytoavailability to guide reclamation practices in acidic soilscapes in northern regions. Can. J. Soil Sci. 92: 253-268. Although soil organic matter and nutrient bioavailability in metal-impacted soilscapes of Sudbury, Ontario, are potentially limiting full ecological recovery, total metal content was used as the critical driver for a 2008 ecological risk assessment. The current greenhouse study evaluated chemical extractants to predict bioavailability of nutrients and contaminant metals to indigenous grasses (Deschampsia). Single extraction methods (0.01 M strontium nitrate, water, 0.01 M calcium chloride, 0.1 M sodium nitrate, 1.0 M ammonium nitrate, 0.1 M lithium nitrate, 1.0 M magnesium chloride, 0.11 M acetic acid, 1.0 M ammonium acetate, 0.05 M ammonium-EDTA, pore water) were examined to assess availability of potentially phytotoxic metals and nutrients in smelter-impacted soils. Extraction procedures to predict phytoavailability were either soil concentration or plant tissue concentration and element dependent. Total and extractable metal concentrations were more correlated for regional contaminant metals (e.g., copper, lead, arsenic, selenium) released by the smelting industry than non-contaminant ones (e.g., iron, calcium, potassium, boron, zinc, molybdenum). The lack of relationship between total and extractable concentrations for most non-contaminant metals suggests total concentration is not a good indicator of phytoavailability for nutrient elements. Stronger correlations between shoot tissue and extractable concentrations were observed for less aggressive extractants (pore water, water, lithium nitrate) reflecting their suitability in predicting phytoavailability over most aggressive ones (except ammonium nitrate).

Leskiw, L. A., Welsh, C. M. and Zeleke, T. B. 2012. Effect of subsoiling and injection of pelletized organic matter on soil quality and productivity. Can. J. Soil Sci. 92: 269-276. Subsoil compaction is a widespread problem in most reclamation and other industrial operations. The objective of our research was to evaluate effectiveness of coupling deep subsoiling with injection of 20 Mg ha^-1 organic matter pellets. Research was conducted at seven sites on a pipeline right-of-way in central Alberta. Treatments were subsoiling, subsoiling with pellets and a compacted right-of-way (control), established in spring and fall 2009. Treatment effects on soil physical properties and nutrient status were assessed in fall 2009 for spring-established sites and on all sites in fall 2010. Density and height of canola plants were determined in late summer 2010. Relative to the control, subsoiling with pellet treatments had lower bulk density in the 20- to 40-cm depth interval (up to 40%) in 2010, particularly in clay-loam soils. This treatment often had higher available phosphorus and total organic carbon in 2010, and total nitrogen in spring treated sites in 2009. Relative to the control, subsoiling with pellets had 46% higher canola plant density in clay loam soils of fall-treated sites. Subsoiling with pellets is recommended on heavy-textured, compacted soils to alleviate compaction and increase plant productivity.