ALBERT

Description: Open-pit mining activities in the oil sands region of Alberta, Canada, create disturbed lands that, by law, must be reclaimed to a land capability equivalent to that existed before the disturbance. Re-establishment of forest cover will be affected by the production and turnover rate of fine roots. However, the relationship between fine root dynamics and tree growth has not been studied in reclaimed oil sands sites. Fine root properties (root length density, mean surface area, total root biomass, and rates of root production, turnover, and decomposition) were assessed from May to October 2011 and 2012 using sequential coring and ingrowth core methods in lodgepole pine ( Pinus contorta Dougl.) and white spruce ( Picea glauca (Moench.) Voss) stands. The pine and spruce stands were planted on peat mineral soil mix placed over tailings sand and overburden substrates, respectively, in reclaimed oil sands sites in Alberta. We selected stands that form a productivity gradient (low, medium, and high productivities) of each tree species based on differences in tree height and diameter at breast height (DBH) increments. In lodgepole pine stands, fine root length density and fine root production, and turnover rates were in the order of high 〉 medium 〉 low productivity sites and were positively correlated with tree height and DBH and negatively correlated with soil salinity ( P  〈   0.05). In white spruce stands, fine root surface area was the only parameter that increased along the productivity gradient and was negatively correlated with soil compaction. In conclusion, fine root dynamics along the stand productivity gradients were closely linked to stand productivity and were affected by limiting soil properties related to the specific substrate used for reconstructing the reclaimed soil. Understanding the impact of soil properties on fine root dynamics and overall stand productivity will help improve land reclamation outcomes. Fine root properties were assessed for 2 years in lodgepole pine and white spruce stands planted on peat-mineral soil mix in reclaimed oil sand sites in Alberta, Canada. The study sites formed a stand productivity gradient of each tree species. Fine root dynamics of lodgepole pine was affected by salinity, while that of spruce by soil compaction along their respective stand productivity gradient. Understanding the impact of soil properties on fine root dynamics and overall stand productivity will help to improve the success of land reclamation.

Description: Environmental Science & Technology DOI: 10.1021/es300858k

Description: 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.

Description: 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.

Description: 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.

Description: 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.