Weed and Nitrogen Management in Wheat under Mid-Hill Conditions of Himachal Pradesh¹

In field experiments conducted during Rabi 1981–82 and 1982–83 it was observed that isoproiuron at 1.25 kg/ha as post-emergence at 2–3 leaf stage of weeds gave better control of weeds as compared to methabenzthiazuron at all the levels in both the seasons. Even the application of isoprotui on at 0.75 kg/ha resulted in effective control of weeds identical to that of methabenzthiazuron at 1.75 kg/ha. The losses of N, P and K were highest in weedy plots, w ereas, weed free and isoproturon ai 1.25 kg/ha being on par with each other recorded significantly lowest nutrient depletion by weeds and higher grain yield than rest of the treatments. Higher net returns were also obtained with isoproiuron 1.25 kg/ha and weed free treatments, while no weeding resulted in a net loss of Rs. 566/ha. Herbicide treated plots when supplied with 100 kg N/ha gave significantly higher net returns over 50 kg N/ha, however, no such differences were observed in weed free and weedy plots.