Efficacy of Herbicides against Weeds in Transplanted Wet Season Rice (Oryza Sativa L.)

Comparative efficacy of different herbicides against weeds in transplanted kharif rice was studied at Agricultural Farm of Institute of Agriculture, Visva Bharati,Sriniketan, West Bengal. The experiment was laid out in a randomized block design with 9 treatments and 3 replications. The results revealed that the major weed flora associated with the transplanted rice during kharif season was mainly comprised of Echinochloa colona, Cyperus iria L., Sphenoclea zeylanica Gaertn. and Ludwigia parvifloraRoxb. Bispyribac sodium @30 g a.i ha 1 applied at 25 days after transplanting was most effective to check all types of weed population and their growth. This treatment also gave the maximum grain yield (5549 kg ha -1 ) and straw yield (5991 kgha -1 ) of rice resulting in lowest weed index (5.61 %) among chemical herbicide treated plots. The highest grain and straw yield value as observed with application of bispyribac sodium @ 30 g a.i ha -1 was statistically at par with that of bispyribac sodium @ 25 g a.i ha -1 at 25 DAT. Therefore, bispyribac sodium @ 25 g a.i ha -1 applied at 25 days after transplanting may be recommended for weed management in transplanted kharif rice.