International Journal of Bioresource Science

Field experiments were conducted at Agricultural Farm of the Institute of Agriculture, Visva-Bharati, Sriniketan, West Bengal, India during wet season (kharif) of 2005 and 2006, respectively to study the efficacy of imazosulfuron on weed growth and productivity of transplanted rice. The soil of the experimental field was clay loam in texture with acidic soil reaction, low in organic carbon and available N and medium in available P₂O₅ and K₂O respectively. Echinochloa colona, Cyperus iria, Hydrolea zeylanica and Monochoria vaginalis were the predominant weeds. Application of imazosulfuron at 50 g/ha at 5 days after transplanting (DAT) recorded significantly lower number and dry weight of total weeds at 45 DAT, higher plant height, leaf area index and dry matter production, higher number of panicles (345 m²), grains per panicle (72) and grain yield (3.9 t/ha) of rice which were at par with weed free and hand weeding twice. The maximum seed yield of 4.4 t/ha was obtained in weed free plots and it was statistically at par with that of hand weeding twice (4.2 t/ha) and imazosulfuron at 50 g/ha (3.8 t/ha). Among the three different dosages of imazosulfuron (i.e 15, 30 and 50 g/ha), application of imazosulfuron at 50 g/ha was found most effective registering higher weed control efficiency and lower weed index.