Redistribution of Extractable Nutrients Following Disc Trenching on Luvisols and Brunisols in Saskatchewan

摘要

Disc trenching is an important silvicultural management tool for cre-ating microsites to ensure the survival and growth of newly planted seedlings. Mounded microsites are thought to be a source ofnutrients for seedling roots; however, little is known concerning how nutrients are redistributed in the soil after disc trenching. Theobjective of this study, therefore, was to determine the redistribution of soil horizons and selected soil chemical properties fol-lowing Delta disc trenching. Three sites were selected on both Luvisol and Brunisol soils in northern Saskatchewan. Soil profileswere excavated and samples collected from 15 × 15 cm grids to a 1-m depth. Samples were analyzed for pH and extractable nitrate(NO ), ammonium (NH ), phosphorus (P), potassium (K) and sulfur (S). Disc trenching concentrated extractable N, P and S in the 34berm microsite compared to the trench microsites. The redistribution of extractable NO , NH and P in the berms compared to the 34trench microsites was 20 times greater for Luvisol sites compared to the Brunisol sites, while extractable K and S were similar between both microsites for each soil. Seedlings planted on these mounded microsites therefore should have a large pool of nutri- ents for plant growth; however, further work is needed to determine patterns of nutrient uptake by seedlings in relation to mound- ed and trench microsites.