WEED-CONTROL AND ECONOMIC RETURNS WITH POSTEMERGENCE HERBICIDES IN NARROW-ROW SOYBEANS (GLYCINE-MAX)

Field studies were conducted at three sites in 1993 and 1994 to evalua te weed control, crop response, and economic returns to 0.5X and 1X po stemergence rates of chlorimuron, chlorimuron plus quizalofop, bentazo n plus acifluorfen, fluazifop plus fenoxaprop, imazethapyr, and imazet hapyr plus clethodim in no-till narrow-row soybean production. Common lambsquarters, ivyleaf morningglory, and common ragweed were controlle d equally with 0.5X rates applied early postemergence and 1X rates app lied mid-postemergence. Control of giant foxtail, large crabgrass, and common cocklebur was generally greater with 1X rates mid-postemergenc e than with 0.5X rates early postemergence. Soybean yields were equiva lent with 0.5X and 1X rates. Soybean yields and net income were highes t with 1X and 0.5X rates of chlorimuron plus quizalofop and imazethapy r plus clethodim, and metolachlor preemergence (PRE) followed by 0.5X bentazon plus acifluorfen.