Exploration of New-Generation Herbicide Combination for Direct-Seeded Rice Cultivation in India

Weed management has emerged as the main constraint to the successful adoption of climate-resilient dry direct-seeded rice (DDSR) in India. Entire-crop failure has been reported in many direct-seeded rice cases, which is the main constraint to adopting this climate-resilient technology among Indian farmers. A two-year field experiment was conducted during the rainy seasons of 2023 and 2024 to identify effective herbicide combinations for the control of diverse weed flora in DDSR. The conventionally recommended herbicides such as bispyribac-sodium, pyrazosulfuron-ethyl, etc., and recently introduced herbicides like florpyrauxifen-benzyl, triafamone, etc., which have not been explored extensively in the DDSR production system in India, were evaluated. It was found that weed management practices considerably influenced the weed density, weed biomass, weed control efficiency, and grain yield in DDSR. Among the herbicide combinations evaluated, pendimethalin at 1000 g/ha as pre-emergence followed by florpyrauxifen-benzyl (1.31% w/w) at 15.3 g/ha + penoxsulam (2.1% w/w) at 20 g/ha as post-emergence at 25 days after sowing provided the most effective broad-spectrum weed control by recording the lowest overall weed density and biomass throughout the crop growth period. Whereas pendimethalin followed by bispyribac-sodium + pyrazosulfuron-ethyl was the most effective against Cyperus spp., pendimethalin followed by triafamone + ethoxysulfuron recorded the lowest density and biomass of Cynodon dactylon. Treatment T4 recorded weed control efficiencies of 88.0, 88.6, and 85.0% at 30, 60, and 90 days after sowing, respectively, and produced a grain yield of 4.67 Mg/ha, which was statistically at par with the weed-free treatment (4.80 Mg/ha). The sequential application of pendimethalin followed by florpyrauxifen-benzyl + penoxsulam provided effective broad-spectrum weed control and maintained rice productivity comparable to the weed-free treatment. Therefore, this herbicide combination is recommended for weed management in dry direct-seeded rice (DDSR) in India.