资源环境科技发展态势分析平台

Two field trials were established to evaluate the use of alkaline-treated biosolids (ATB) to offset current or predicted Ca deficits in Nova Scotia forest soils under juvenile white spruce (Picea glauca) plantations. At the rates applied (7.5 and 15 t ha(-1) wet weight), ATB treatments led to significant increases in total and available Ca within the forest floor and surface mineral soil, significant increases in forest floor pH, significant or near significant decreases in exchangeable forest floor Al3+ concentrations, and negligible leaching of metals (Cu, Cd, Pb, Zn) for the 2-year duration of study. Near-surface PO43--P availability was also slightly enhanced after an initial delay period. However, despite relatively high K concentrations in the ATB product used, there were no significant increases in forest floor K concentrations, suggesting a relatively rapid release and movement of K+ to deeper soil layers compared to Ca2+. There were also no significant increases in forest floor Mg concentrations, or in total and available N. Results suggest that ATB could be a good source of Ca in Ca-limited sites, but nutrient imbalances may be a problem on sites where K and Mg depletion has also occurred or where N is also limiting.