Cover Crop Interseeding Effects on Establishment, Weed Control, and Crop Yield.

The benefits of winter cover crops (WCC) are widely documented, but the adoption rate remains low among grain producers. Farmers cite timely cover crop establishment as the greatest obstacle to integrating WCCto their existing cropping systems. Interseeding cover crops into cash crops prior to harvest is one potential solution to overcoming this obstacle. A new machine called the InterSeeder allows for drill seeding cover cropsbetween existing 76-cm rows of cash crops such as corn or soybean. The objective of this research was to evaluate the effects of interseeding cover crops on fall and springaboveground biomass in both on-farm and research farm trials in the Pennsylvania, Maryland, and New York.Effects of interseeded cover crop treatments on weed control and crop yield were also examined. Interseeded cover crops were evaluated on grain corn [Zea mays], silage corn, and soybean [Glycine max] systems usingcrop management practices specific to each farm site. Arandomized complete block design with at least 3 replications was used at each site. Cover crop treatments included 1) annual ryegrass [Lolium multiflorum], 2) daikon radish [Raphanus sativus], 3) hairy vetch [Vicia villosa] + crimson clover [Trifolium incarnatum] + red clover[Trifolium pratense], 4) hairy vetch [Vicia villosa] + crimson clover [Trifolium incarnatum] + red clover [Trifoliumpratense] + annual ryegrass [Lolium multiflorum], and 5)no cover crop control. Interseeded cover crop establishment was variable across sites. Some sites exhibited significant biomass whereas others experiencedcover crop herbivory, unfavorable soil seedbed conditions, and excessive light competition due to crop canopyclosure. Across sites the grass-legume mixture treatment achieved the greatest fall and spring abovegroundbiomass.