Efficacy of metsulfuron methyl for controlling broadleaf weeds in transplanted rice (Oryza sativa) under rainfed shallow lowland.

All the herbicidal treatments were significantly superior to weedy check. There was more than 44% reduction in the grain yield of rice due to competition with weeds in the weedy plots. The highest grain yield (4.96 tonnes/ha) and N-use efficiency (62.0) were obtained in weed-free check. Among the tested herbicides, metsulfuron methyl 8 g/ha applied 10 days after transplanting was found to be the most effective herbicide (weed control efficiency 87.9%) in controlling the pre-dominant weeds, and thereby realizing an increase of 72% yield over weedy check. It was comparable with weed-free check. The N-use efficiency (59.8) was also higher in metsulfuron methyl (8 g/ha), followed by tank-mix application of metsulfuron methyl + chlorimuron ethyl at 4 +6 g/ha (57.9) and chlorimuron ethyl at 8 g/ha (55.8).