Studies on long term uses of herbicides in rice-wheat cropping system

Present study is in progress since 1990-91 at Crop Research Centre of G. B. Pant University of Agriculture and Technology, Pantnagar, U.S.Nagar (Uttaranchal) to study the long term effects of herbicide use in rice-wheat system. Treatments consisted of combinations of butachlor at 1.5 kg ha-1,hand weeding (30 and 60 days after transplanting) and weedy check in rice and each kharif season treatment followed by isoproturon at 1.0 kg ha-1,hand weeding twice (30 and 60 days after sowing) and weedy check in wheat. Experiment was laid out in randomized block design, with nine treatments and three replications. The soil of experimental plot was sandy loam in texture, medium in organic carbon, low in available nitrogen and medium in available phosphorus and potassium with neutral soil reaction. The various studies conducted during Kharif and rabi season of 2003-04 and 2004-05 are presented here.