AUTHOR=Yang Xueming , Reynolds W. Daniel , Drury Craig F. , Reeb Mary-Anne 

TITLE=Impacts of summer-seeded legume cover crops and termination-tillage method on nitrogen availability to corn in rotation

JOURNAL=Frontiers in Soil Science

VOLUME=2

YEAR=2023

URL=https://www.frontiersin.org/journals/soil-science/articles/10.3389/fsoil.2022.1082940

DOI=10.3389/fsoil.2022.1082940

ISSN=2673-8619

ABSTRACT=<p>Summer-seeding legume cover crops can reduce erosion, mitigate nitrate leaching losses during the non-growing season, and provide bio-accumulated nitrogen (N) to the following crop. Very little information is available, however, on the most effective methods for terminating summer-seeded cover crops, or on the amount of N they can provide to subsequent crops. We therefore evaluated the impacts of selected legume cover crops and cover crop termination-tillage methods on corn (<italic>Zea mays</italic> L.) N credit and grain yield in a soybean (<italic>Glycine max</italic> Merr.) - winter wheat (<italic>Triticum aestivum</italic> L.)/cover crop - corn rotation over 3 consecutive years on a clay loam soil in southwestern Ontario. The cover crops were summer-seeded after wheat harvest, and included hairy vetch (<italic>Vicia villosa</italic> L. Roth), red clover (<italic>Trifolium pratense</italic> L.), white clover plus crimson clover mix (<italic>incarnatum</italic> and <italic>Trifolium alba</italic> L.), and a no cover crop control (CK). The cover crops were nested within termination-tillage method, including moldboard plow-down in fall, and herbicide spray-down in spring under strip-tillage or no-tillage then corn planting. Nitrogen fertilizer to corn was applied <italic>via</italic> side-dress at 200 kg N ha<sup>-1</sup> to the CKs, and at 100 kg N ha<sup>-1</sup> to the cover crops. Averaged over 3 years, above-ground biomass N level followed the pattern: hairy vetch &gt; white clover plus crimson clover mix &gt; red clover for fall plow-down termination. There were no significant differences in cover crop biomass N levels for spring termination. Corn response to cover crop was significantly affected by termination-tillage method and cover crop species, with poor corn stands after no-tillage, red clover and white plus crimson clover. Fall plow-down termination provided a range in N credit of 80-85 kg N ha<sup>-1</sup>, which was significantly greater than the N credit under herbicide spray-down in spring. Under spring strip-tillage and no-tillage, hairy vetch produced significantly greater corn grain yields than red clover and white plus crimson clover mix.</p>