|Radke, J - RETIRED ARS|
|Laflen, J - RETIRED ARS|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 13, 2000
Publication Date: N/A
Interpretive Summary: Oat and rye cover crops have the potential to reduce erosion following soybean in Iowa, but cover crop growth between soybean harvest and corn planting is limited. Overseeding oat and rye cover crops into soybean in August establishes the cover crops before soybean leaf drop and results in more growth in the fall. An oat cover crop will winterkill in the northern Corn Belt, but rye regrows in the spring. This research showed that overseeding oat and rye cover crops into soybean in August can reduce erosion in the spring, especially on sites where overland water flow occurs. Additionally, in management systems or in years when the soybean crop does not produce adequate residue to cover the soil, the oat and rye cover crops will supplement residue cover and anchor existing residues. Thus, oat and rye cover crops can improve soil conservation between soybean harvest and corn planting in the upper Midwest. These findings will be of use to action agencies and farmers alike.
Technical Abstract: Oat and rye cover crops have the potential to reduce erosion following soybean in Iowa. Oat and rye cover crops were overseeded into no-till soybeans in August of 1995, 1996, and 1997 on a sloping site. Infiltration, runoff, and erosion were measured in April of 1996, 1997, and 1998 using an oscillating sprinkler-head rainfall simulator that applied water at approximately 125 mm hr**-1. Rill erosion was measured by making flow additions to the upslope end of plots. All measurements were made concurrently on tracked and untracked interrows. Cover crops had no effect on erosion or infiltration in 1996. In 1997, both oat and rye cover crops reduced interrill erosion, but in 1998 only rye increased infiltration and reduced interrill erosion and runoff. Untracked interrows had less interrill erosion and runoff, and more infiltration than tracked interrows. In 1997 and 1998, both oat and rye cover crops reduced rill erosion resulting from overland water flow. Wheel traffic had no measurable effect on rill erosion. Thus, oat and rye cover crops can improve soil conservation between soybean harvest and corn planting in the upper Midwest.