Management Techniques for Perennial Cover Crops.

Increasing continuous vegetative cover in the upper Midwest is critical to mitigating the environmental consequences of conventional agricultural practices. Cover crops provide an effective, plant based solution to nutrient losses in the corn-soybean crop rotation, specifically with perennial species that provide year-round soil protection. The objective of this study was to maximize cash crop yield while maintaining perennial cover crop establishment. The study took place across three locations in Minnesota using either tillage or chemical suppression treatments of perennial cover crops in both corn and soybean. Perennial covers used in this study were as follows: chewings fescue (Festuca rubra), hard fescue (Festuca brevipila), kura clover (Trifolium ambiguum), a legume mix consisting of clover species + birdsfoot trefoil (Lotus corniculatus), and crown vetch (Securigera varia). Cash crop seed beds were prepared using either rotary-zone tillage strips or herbicide killed strips in perennial species. Perennial cover crops were suppressed using low rates of glufosinate (1.66 kg ha^-1). Our early season biomass results and our growth staging data support our qualitative hypothesis: the greater perennial cover biomass, particularly in the fescue species, the more adverse impacts on the yield of cash crop. Strategic placement of perennial cover crops may be applied to challenging watersheds or highly erodible land to both protect the soil and nutrients and to provide an economic incentive to growers.