Effect of different weed control treatments on weed growth and rice yield in uplands

摘要

A field experiment conducted during wet season of 1997 and 1998 at Palampur revealed that, when the herbicides cyhalofopbutyl, butachlor and 2,4-DEE were used alone, application of cyhalofopbutyl at 90 g a.i. ha~(-1) and 2,4-DEE at 1.0 kg a.i. ha~(-1)20 days after sowing (DAS) was more effective in controlling grassy weeds and sedges/broad-leaf weeds, respectively. The sequential application of cyhalofopbutyl at 90 g a.i. ha~(-1) (20 DAS) followed by 2,4-DEE atl.0kg a.i. ha~(-1) (30 DAS) was as effective as the farmer's practice (an interculture operation with desi plough in standing water followed by two hand weedings) and superior to their tank mix application in controlling the total weed flora. The farmer's practice resulted in the highest grain yield of rice (cv. HPU 2216), whereas application of cyhalofopbutyl at 75 g a.i. ha~(-1) (20 DAS) followed by butachlor at 1.0 kg a.i. ha~(-1) + 2,4-DEE at 1.0 kg a.i. ha~(-1) (30 DAS) was at par with it in both the years. Tank mix application of 2,4-DEE with cyhalofopbutyl and butachlor proved to be antagonistic for the control of grassy weeds and thereby caused significant reduction in the grain yield.