Seeding Technique and Date Effect on Cover Crop Establishment. The highboy seeding technique allows for an early seeding date that resulted in additional cover crop growth when compared to the drilled treatment that followed corn and soybean harvest. When comparing biomass of cover crop mixtures, the cereal rye and oats in the cover crop mixes made up the majority of the growth recorded. Corn and soybean yields tended to be unaffected by the cover crops.