|Chen, Senyu - UNIVERSITY OF MINNESOTA|
|Wyse, Donald - UNIVERSITY OF MINNESOTA|
|Johnson, Gregg - UNIVERSITY OF MINNESOTA|
|Porter, Paul - UNIVERSITY OF MINNESOTA|
|Miller, Daniel - UNIVERSITY OF MINNESOTA|
|Betts, Kevin - UNIVERSITY OF MINNESOTA|
|Klossner, Lee - UNIVERSITY OF MINNESOTA|
|Haar, Milton - UNIVERSITY OF MINNESOTA|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 22, 2006
Publication Date: July 25, 2006
Citation: Chen, S., Wyse, D.L., Johnson, G.A., Porter, P.M., Stetina, S.R., Miller, D.R., Betts, K.J., Klossner, L.D., Haar, M.J. 2006. Effect of cover crops alfalfa, red clover, and perennial ryegrass on soybean cyst nematode population and soybean and corn yields in minnesota. Crop Science. 46:1890-1897. Interpretive Summary: Over the past three decades, soybean cyst nematode (SCN) has become the major pest problem on soybean in the North Central region of the United States. The nematode can reproduce rapidly in a single soybean season and can survive well in the absence of host plants, so two or more years of growing a crop that the nematode cannot use as food are often needed to suppress the population enough to avoid economic loss. Growers in this region typically plant soybean and corn in alternating years, so modifying this cropping system to include cover crops that do not support SCN growth and reproduction may help reduce damage by the nematode. Red clover and alfalfa interseeded with soybean reduced the number of SCN eggs slightly as compared to plots without cover crops, though this reduction was attributed in part to reduced soybean growth because of competition between the crop plant and the cover crop. Perennial ryegrass did not affect SCN populations in most cases. Because competition with the cover crops was a factor that contributed to lower crop growth and yield, planting these cover crops at the same time soybean is planted is not recommended. Later planting dates may be more appropriate for beneficial use of these cover crops in the soybean-corn rotation system in Minnesota.
Technical Abstract: An experiment was carried out to evaluate alfalfa, red clover, and perennial ryegrass as cover crops for their effects on soybean cyst nematode (SCN) and soybean and corn yields in Waseca, Lamberton, and Rosemount, Minnesota. The cover crops were interseeded in soybean at 0 or 2 weeks after planting soybean in 2002 and killed with herbicide prior to planting corn in 2003. As expected, SCN-susceptible soybean supported higher SCN egg population density than SCN-resistant soybean. Red clover and alfalfa reduced the SCN population density, probably due to reduced soybean growth, but the effect was minimum and inconsistent. While perennial ryegrass did not affect SCN egg population density in most cases, higher egg population densities in the perennial ryegrass treatment compared with the control were observed at Waseca. SCN-resistant soybean produced higher yield than susceptible soybean at all sites. The cover crops, especially those planted the same time with soybean, reduced soybean yield in some cases but not all. No difference in corn yield was observed at Waseca. At Lamberton, alfalfa and red clover planted at the same time as soybean and perennial ryegrass planted 2 weeks after planting soybean reduced corn yield in 2003. At Rosemount , reduction of corn yield was observed with red clover interseeded in SCN-susceptible soybean and with all three cover crops interseeded in SCN-resistant soybean at the same time. The results suggest that a later planting date may be more appropriate for beneficial use of these cover crops in the soybean/corn rotation system in Minnesota.