Effect of Wheat Residue and Tillage onHeterodera glycinesand Yield of Doublecrop Soybean in Kentucky

Abstract

A study (1990 to 1992) was conducted in western Kentucky to determine the effects of wheat (Triticum aestivum «Clark») residue and minimal- (two disking) or no-tillage on soybean cyst nematode (Heterodera glycines) cyst and egg population densities and yield of the H. glycinessusceptible soybean (Glycine max) cultivar Pennyrile. In each year, cyst densities at soybean planting were unaffected by the presence of residue from a prior winter wheat crop; however, harvest population densities were lower in plots with wheat residue compared with those without residue. Across residue treatments, tillage had no effect on harvest densities of cysts in any year. Differences in egg densities, determined only in 1992, were similar to differences detected in cyst densities for both residue and tillage. Minimum-tillage of wheat residue significantly reduced the «residue effect» in 1990 and 1991; however, plots with wheat residue had fewer cysts at harvest than plots without residue in both years regardless of tillage method. Neither residue nor tillage affected soybean yields. Results indicate that producers who have the option to no-till doublecrop soybean following wheat may have an advantage in long-term management of H. glycines