Vialykh, E. A., Ilarionov, S. A., Abdelrahman, H. M. and Vialykh, I. A. 2014. Changes in amino acids content of humic acids sequentially extracted from peat and sod-Podzolic soil. Can. J. Soil Sci. 94: 575-583. Amino acids (AA) and peptides are thought to be part of humic acids (HA), but debate whether they are an integral part of the HA is still going. Humic acids sequentially extracted from peat and sod-podzolic soil were analyzed for their AA content, elemental composition and by Fourier transform infrared spectroscopy. Extracted HA were hydrolyzed in 6 M HCl for 16 h for AA release, which was detected by a capillary electrophoresis system. Alanine, arginine, sum of aspartic acid and asparagine, sum of cysteic acid and cysteine, sum of glutamic acid and glutamine, glycine, histidine, leucine and isoleucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, valine were identified. The total content of hydrolyzable AA in sod-Podzol HA increased by 6.2-8.2% with increasing the extraction cycles while an inverse tendency was observed for AA released from peat HA. Moreover, individual AA expressed as percentages of total AA were constant values with coefficients of variation lower than 20% for the studied HA.

Jobin, P., Caron, J. and Rochefort, L. 2014. Developing new potting mixes with Sphagnum fibers. Can. J. Soil Sci. 94: 585-593. Researchers are developing techniques to mass produce Sphagnum fibers (SF) on a sustainable basis since this material has properties that could benefit the growing-media industry. The objective of this study was to incorporate SF into peat-based substrates to enhance the value of brown Sphagnum peat and/or replace perlite in blond peat mixes. Nine substrates were prepared by mixing brown Sphagnum peat (BrSP) or sieved brown Sphagnum peat (sBrSP) with 0, 15 and 30% of SF and substituting 0, 50 and 100% of the perlite in a 70% blond Sphagnum peat (BSP) and 30% perlite mix with SF. The growth of Pelargonium was unaffected by the addition of SF, with the exception of above-ground biomass which was 15% lower in the BrSP substrate containing 15% SF. In the case of Petunia, above-ground biomass increased with a 30% SF addition to sBrSP, and below-ground biomass increased with a 30% SF addition to BrSP and sBrSP. Adding SF to peat increased water retention and hydraulic conductivity, but either reduced or had no impact on air-filled porosity. Removing fine particles from BrSP and adding 30% SF provided promising results, although the effect varied with plant species. Moreover, it is clear that SF can be used as a substitute for perlite in BSP mixes.

Gillis, J. D., Price, G. W. and Stratton, G. W. 2014. Detection and degradation of organic contaminants in an agricultural soil amended with alkaline-treated biosolids. Can. J. Soil Sci. 94: 595-604. The agricultural use of wastewater biosolids is a common practice in many countries, but concerns exist regarding the presence of organic wastewater contaminants that remain in the land-applied biosolids. The objective of this study was to determine if contaminants present in biosolids are detectable in soil following land application. A suite of organic contaminants were monitored by gas chromatograph with mass spectrometer in agricultural soil samples from a site amended with increasing rates of alkaline-treated biosolids. Triclosan, a common antimicrobial agent, was detected at levels greater than the reporting limit in an environment-controlled incubation study and validated through in situ field samples from soils receiving the same alkaline-treated biosolid. A rapid decrease in triclosan concentration was observed during the first few weeks of the incubation study, with concentrations decreasing from 92±26 to 20±2 ng g^-1 (average 78% decrease) after 4 mo. The field results indicate that triclosan in fall-applied may persist overwinter. However, a rapid decrease in triclosan concentration during the spring and summer months led to levels lower than predicted following the spring application, and levels below our reporting limit (up to 85% decrease) by the end of the study. Removal is posited to be through aerobic microbial degradation.

Olatuyi, S. O. and Leskiw, L. A. 2014. Long-term changes in soil salinity as influenced by subsoil thickness in a reclaimed coal mine in east-central Alberta. Can. J. Soil Sci. 94: 605-620. Elevated salinity and sodicity are major challenges to reclamation of surface-mined coal sites in the Alberta Plains region. Research plots were established in 1981 at the Battle River Coal Mine near Forestburg, AB, to determine an optimum depth of subsoil replacement over sodic mine spoil required to sustain agricultural capability. Subsoil thickness was varied at 0, 25, 65, 135, 165 and 335 cm, overlain with 15 cm topsoil. The plots were monitored annually from 1982 to 1986 and were seeded to forage from 1987. Plots were resampled in 2013 to examine long-term changes in soil quality by comparing the results with the historical means for the 1980s. Key soil parameters measured are pH, electrical conductivity (EC), total dissolved salts (TDS), sodium adsorption ratio (SAR) and soluble Na. The soil quality of the root zone (0-40 cm) improved over time in all treatments as EC, TDS, SAR and concentration of Na decreased significantly between the 1980s and 2013. Amounts of EC and soluble Na consistently increased with depth, suggesting salt accumulation was predominantly by downward leaching, but with contribution by upward migration of Na from the underlying spoil. Relative to the native soils in 2013, the root zone quality ratings for EC and SAR in the topsoil/spoil treatment were better than in the shallow-bedrock Solonetzic soil. Ratings for the 25-cm subsoil treatment were also comparable with the local Chernozemic soil, but better than the fine till Solonetzic soil. This study demonstrates that a minimum of 25 cm subsoil and 15 cm topsoil are required for mitigating salinity and sodicity in these reconstructed soils. The resampling in 2013 demonstrates that long-term monitoring is essential to obtain a better understanding of reclamation outcomes.

Pugliese, S., Jones, T., Preston, M. D., Hazlett, P., Tran, H. and Basiliko, N. 2014. Wood ash as a forest soil amendment: The role of boiler and soil type on soil property response. Can. J. Soil Sci. 94: 621-634. Wood ash is produced in large quantities in Canada as a by-product of the pulp and paper, sawmill, and bioenergy industries and it is anticipated that its disposal in landfills will not be a viable option. An alternative option may be to use it to amend forest soils. Wood ash is a complex mixture and its composition depends on several variables, including the combustion parameters of the boiler in which it is generated. We present an analysis of the amendment of two Canadian forest soils (a Brunisol from the Great Lakes-St. Lawrence and a Luvisol from the Carolinian forest regions of Ontario) with six different wood ashes collected from different biomass boilers through short-term controlled incubations. We show that following an 8-wk incubation period, amendment of the soils with wood ash led to small to moderate increases in soil pH, but had little effect on soil microbial activity and biomass. The concentration of important base cations such as calcium, magnesium and potassium as well as phosphorus generally increased in both soil types following amendment with different ash. This practice can return nutrients lost from forest ecosystems during harvesting; however, effects were found to be boiler-specific. Lastly, we show that four ash types led to small increases in cadmium in either soil; the concentration of all other measured heavy metals was not significantly increased following amendment, and in certain cases decreased, particularly with lead. The only potentially negative aspect encountered was elevated sodium, particularly with ash from one boiler, but unacceptable Na-absorptivity ratios were not exceeded. These results demonstrate that with proper characterization and selection of wood ash type and application rates, amendment of Canadian forest soils with wood ash may benefit forest ecosystems and is unlikely to disrupt the chemical and biological processes in soil environments.