Efficacy of Linuron and Fluazifop-p-butyl against Weeds in Soybean (Glycine max)

Field experiment was conducted in 1996 and 1997 to evaluate the efficacy of new herbicides against broadleaf and grassy weeds in soybean. Pre-emergence application of linuron at 1250 g ha−1 provided 85% control of carpetweed, 68% of digera and 75% of barnyard grass. Post-emergence application of fluazifop at 750 to 1000 g ha−1 provided 70 to 90% control of barnyard grass but failed to control any of the broadleaf weed. Sequential application of pre-emergence linuron and post-fluazifop at 750 and 500 g and 1000 and 500 g ha−1 provided better control of all weeds than their single application. intergration of lower rates of preemergence linuron 750 or 1000 g ha−1 with one hand weeding at 40 DAS provided excellent control of all weeds and similar to trifluralin followed by hand weeding. Higher rate of soil applied linuron, and when lower rate was integrated with post-em. fluazifop or one hand weeding produced better yield attributes i. e. branches and pods per plant and consequently higher grain yield of soybean than unweeded control and at par to weed free yield. Post-emergence application of linuron proved phytotoxic to soybean.