Competition of Elytrigia repens and Apera spica-venti in winter wheat and possibilities of weed management using sulfosulfuron applications

In three-year field experiments competition between winter wheat and two we ed species, Elytrigia repens and Apera spica-venti, in relation to competit ion ability of the crop was examined. Crop yield was reduced to a greater e xtent by competition with Elytrigia repens than with Apera spica-venti. The rectangular hyperbola can be used to describe the response of winter wheat yield to Elytrigia repens density. In opposite, the data for Apera spica-v enti density - yield relationship were fitted to linear model. The dose res ponse relationships for Elytrigia repens depend strongly on competition abi lity of the crop. This effect on dose-response curves for Apera spica-venti was not investigated. The way for adjusting the herbicide dose using yield and dose-response relationships is presented.