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Title: OATS OVERSEEDED INTO SOYBEAN AS A FALL COVER CROP

Author
item JOHNSON, TIMOTHY - IOWA STATE UNIVERSITY
item Kaspar, Thomas
item Kohler, Keith

Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/14/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Fields that have been planted to soybean are often susceptible to erosion after harvest because of inadequate residue cover. Cover crops have been used in the East and South to address this problem, but have rarely been used in the upper Midwest because of the cold and short growing season following soybean harvest. One way to overcome this problem is to overseed an oat cover crop into soybeans before harvest. Oats grow well in cool weather, the seed is inexpensive, and will germinate and survive under a soybean canopy. The possibility exists, however, that an oat cover crop could reduce yields of both the soybean and the following corn crops. A study was conducted from 1991 to 1995 to examine the effect of an oat cover crop on corn and soybean yields. Overseeding oats into soybean reduced soybean yield in one of five years and had no effect on corn yield. Another objective of this study was to develop a method of predicting the potential for oat cover crop growth at a given location. Producers need some estimate of cover crop growth to determine whether it is worth doing at their location. We surmised that growing degree days, precipitation, and soybean yield were factors that affected the amount of cover crop growth in the fall. Using these three factors we were able to get good agreement between predicted and actual values. In the future, we hope to use this equation to prepare maps of the upper Midwest showing potential oat cover crop growth based on climate normals.