V.T. Mukeshkumar, P. Sudhakar, S. Kandasamy, S. Manimaran and K. Dhanasekaran
Abstract
Direct-seeded rice (DSR) is emerging as a sustainable alternative to transplanted rice owing to its lower water requirement, reduced labour dependency and decreased production costs; however, heavy weed infestation remains a major yield-limiting factor. A field experiment was conducted during samba season (August-December, 2023) with the rice variety TKM 13 at the Experimental Farm of the Department of Agronomy, Annamalai University, to evaluate different weed management strategies in DSR. The study comprised eight treatments involving combinations of pre-emergence, early post-emergence, and post-emergence herbicides integrated with hand weeding, along with a weedy check and hand weeding twice at 15 and 30 DAS, laid out in a randomized block design. Pre-emergence applications included pretilachlor, pyrazosulfuron-ethyl, and their ready-mix followed by hand weeding at 15 DAS, while early post-emergence treatments involved metsulfuron-methyl, bispyribac-sodium, triafamone+ ethoxysulfuron, and metsulfuronmethyl + chlorimuron-ethyl with hand weeding at 30 DAS; 2,4-D was applied as a post-emergence herbicide. Herbicide-based treatments significantly reduced weed infestation, lowering weed biomass by 58-98% at 50 DAS. Among the treatments, triafamone + ethoxysulfuron followed by hand weeding at 30 DAS was most effective, achieving 90.8-96.7% weed control efficiency and producing higher grain yield (3667-5080 kg ha-¹). The study concludes that integration of new-generation herbicides with cultural practices is an effective strategy for improving weed control, and productivity in direct-seeded rice systems.