Broadcast Seeding Rates for Cereal Rye, Hairy Vetch and Forage Collard Cover Crops.

In corn-soybean systems, planting cover crops into standing main crops in early fall allows for longer fall growth and leads to higher cover crop biomass production in the spring than planting cover crops after main crop harvest. Currently, cover crop seeding into standing corn and soybeans can only be accomplished by broadcasting seeds on the ground, either by airplane or with a cover crop interseeder. Because broadcasting often results in lower emergence, recommended seeding rates may need to be adjusted. In this study, three species of cover crops (grass, legume and brassica) were broadcast planted at three seeding rates into corn or soybean stands in mid-September at two locations in Nebraska. Cereal rye seeding rates were 60, 90 and 120 lb acre^-1, hairy vetch seeding rates were 40, 60 and 80 lb acre^-1 and forage collard seeding rates were 10, 15 and 20 lb acre^-1. Cover crops were terminated in early May, just before main crop planting. In the fall of the first year of this three year study, cover crop emergence was less than 8% for each species by seeding rate combination. Overall plant counts were highest for collards. However, collards winterkilled, vetch biomass was low, and rye biomass was high. Results from this study will provide information on broadcast seeding rates for cover crops in the prevalent cropping systems in Nebraska.