Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 1998
Publication Date: N/A
Technical Abstract: Corn-soybean rotations in the Midwest are susceptible to erosion following soybean harvest because soybeans don't leave enough residue to adequately protect the soil and because their residue decomposes quickly. Oat and rye cover crops overseeded into soybean in August have the potential to increase surface residue cover following soybean harvest and to anchor and stabilize residues. Oat and rye cover crops were overseeded into no-till soybean (76-cm rows) in August of 1995, 1996, and 1997 on sloping plots. Wheel traffic was controlled on the plots and measurements were made concurrently in tracked and untracked interrows. Infiltration, runoff, sediment load, and time to first runoff were measured in late April using an oscillating sprinkler-head rainfall simulator that applied water at approximately 125 mm/hr. Rill erosion was measured by making flow additions to the top of the plots at the end of the rainfall simulation. Residue cover, bulk density, and initial soil water content were also measured. Wheel traffic had a greater impact than cover crops on interrill erosion, sediment load, infiltration, runoff, and time to first runoff. Untracked interrows had less sediment and runoff, more infiltration, and a greater time to first runoff than tracked interrows. In 1997, oat and rye cover crops reduced interrill erosion and in 1998 rye reduced interrill erosion and runoff rate. Thus, oat and rye cover crops seem to be a useful tool for reducing erosion where soybean residue cover is below acceptable levels and where overland water flow occurs.