Hairy Vetch Green Manure; Influence of Termination Method on Earthworm Populations.

Agriculture is a major source of soil degradation worldwide. In order ensure the long-term viability of food production soil health is going to need to be maintained and improved. This research examines the use of hairy vetch (Vicia villosa Roth) as a green manure (GMr) in Atlantic Canada and Southern Manitoba to improve soil health under various termination practices. Data presented here will be from the Atlantic Canada location only. In Truro, NS, a fully-phased four-year organic grain crop rotation (hairy vetch-wheat-fall rye-soybean) with varying levels of GMr tillage intensity was established in 2013. Three levels of GMr termination are being employed; fall tillage (tilled in the fall and spring), spring tillage (rolled in fall, tilled in spring), and no-till (crop-rolled only). Soil is being sampled throughout the growing season in the vetch, wheat, and fall rye phases of the rotation to determine the effects on soil health. In fall 2013 hairy vetch GMr biomass averaged 5.4 t/ha with the most productive plot producing over 10 t/ha. The average biomass of mulch remaining in spring 2014 was 4.90 t/ha, showing good overwinter persistence of GMr biomass on the soil surface. Earthworm abundance was sampled in June, 2014. No-till plots had 91.0 earthworms m^-2 while fall and spring till treatemtns produced 15.3 m^-2 and 7.0 m^-2, respectively. The no-till wheat plots were also cooler and had greater soil moisture levels during the spring, conditions which are favourable to earthworms. The differences in earthworm abundance are likely caused by decreased soil disturbance in no-till GMr system combined with the favourable soil environment created by the mulch it generates.