Management of Complex Weed Flora in Peas with Herbicide Mixtures under Lahaul Valley Conditions of Himachal Pradesh

Field experiment was conducted for two consecutive summer seasons (1999 and 2000) at Kukumseri on sandy loam soil to evaluate promising herbicide combinations for weed control in pea. Alachlor at 1.0 kg+pendimethalin at 0.9 kg ha−1 and alachlor at 1.0 kg+ isoproturon at 1.0 kg ha−1 were statistically similar to alachlorat 1.5 kg ha−1, pendimethalin at 1.2 kg ha−1 and hand weeding twice in reducing density and dry weight of weeds. These were significantly suprior in reducing weed density and weight as compared to other treatments. Alachlor at 1.0 kg+pendimethalin at 0.9 kg ha−1 recorded the highest weed control efficiency of 87.5%. Pendimethalia 1.2 kg ha−1 gave highest grain yield which was significantly higher than pendimethalin at 0.9 kg+isoproturon 0.75 kg ha−1, pendimethalinat 0.6 kg+isoproturon at 1.0 kg ha−1, pendimethalinat 0.6 kg+isoproturon at 0.75 kg ha−1 and alachlor at 0.75+isoproturon at 0.75 kg ha−1. Alachlor at 1.50 kg ha−1 recorded highest marginal benefit cost ratio (MBCR). The combinations of alachlor at 0.75–1.00 with isoproturon at 0.75, 1.00 kg ha−1 were superior to other herbicide treatments in increasing MBCR.