Sole and combined application of herbicides on composite weed flora of transplanted rice

Field experiments were conducted during Kharif (wet) seasons of 2014 and 2015 at Agricultural Farm, Institute of Agriculture, Visva-Bharati, Sriniketan, West Bengal, with rice variety ‘MTU-7029’ to study the effect of sole and combined application of different herbicides on growth of composite weed flora and productivity of wet season transplanted rice. Eleven treatments were assigned in a randomized block design with three replications. Echinochloa colona and Paspalum distichium among the grasses; Cyperus iria, among the sedges and Ludwigia parviflora among the broad-leaved weeds were predominant throughout the cropping period. Azimsulfuron at 35 + 2, 4-D at 500 g/ha at 25 DAT effectively controlled the complex weed flora recorded at 50 DAT which was statistically at par with pretilachlor at 750 g + pyrazosulfuron-ethyl at 25 g/ha at 3 DAT. Weed competition reduced the grain yield of rice to the tune of 33–35%. Lower values of weed density, total weed dry weight and higher values of weed control efficiency and yield of rice were registered with combined application of azimsulfuron at 35 g + 2, 4-D at 500 g/ha at 25 DAT and it was followed by pretilachlor at 750 g + pyrazosulfuron-ethyl at 25 g/ha at 3 DAT. These treatments could be recommended for managing complex weed flora and obtaining higher yield of transplanted Kharif (wet) rice in the lateritic belt of West Bengal, India.