Effects of Four Herbicides on Four Early Maturing Soybean (Glycine max) Cultivars

Tolerance of two metribuzin-tolerant and two metribuzin-sensitive early maturing soybean cultivars to two rates of acifluorfen, imazethapyr, metribuzin, and thifensulfuron was evaluated under weed-free conditions. Acifluorfen at 1120 g ai ha -1 reduced plant height by 3 cm and thifensulfuron at 18 and 35 g ai ha -1 delayed physiological maturity by 3 d. No herbicide treatment reduced soybean yield when compared with a weed-free check. Soybean yield of the two metribuzin-tolerant and the two metribuzin-sensitive cultivars did not change as metribuzin rate was increased from zero to 280 to 560 g ai ha -1 .