Integrating Reduced Rates of Postemergence Herbicides and Cultivation for Broadleaf Weed Control in Soybeans (Glycine max)

The interaction of reduced rates of bentazon, chlorimuron, imazaquin, and imazethapyr with cultivation for broadleaf weed control in soybeans was investigated in field experiments conducted at three sites in Missouri in 1987 and 1988. Single reduced-rate herbicide applications provided soybean yields equal to full rates although visual weed control was slightly lower. Sequential applications of all four herbicides at reduced rates provided weed control and soybean yields equal to full-rate applications. The number of velvetleaf plants m−2 and seeds plant−1 were not influenced by herbicide, herbicide rate, or application timing. Cultivation improved weed control and soybean yield and decreased late-season weed populations and seed production.