Efficacy of integrated weed management (IWM) practices on the weed dynamics, production and productivity of direct-seeded rice

This study assessed the efficacy of Integrated Weed Management (IWM) practices on weed dynamics, crop resistance, weed persistence and the production and productivity of direct-seeded rice during the Kharif seasons of 2021 and 2022 at the Agronomical Research Farm, BAU, Ranchi, on sandy loam soil. Twelve IWM treatments, incorporating varying herbicidal doses and inter-culture practices, were evaluated. The weed composition was predominantly grassy (37.59 %), sedge (41.24 %) and broad-leaved (21.16 %) species. The highest weed density and dry weight at 60 days after sowing (DAS) were recorded in the weedy check. Weed Management Efficacy was quantified using indices such as Weed Control Index (WCI), Weed Persistence Index (WPI) and Crop Resistance Index (CRI). The most effective treatments included three hand weedings and the combination of Pretilachlor (1.00 kg a.i./ha, pre-emergence) followed by Bispyribac Sodium (0.025 kg a.i./ha, post-emergence at 20 DAS). Both treatments resulted in significantly higher grain (41.70 q/ha) and straw yield (61.30 q/ha) compared to the weedy check. Economic analysis revealed that Pretilachlor + Bispyribac Sodium provided the highest net return (Rs. 67,064 per ha) and benefit-cost ratio (B: C ratio), followed by three hand weedings (Rs. 58,741 perha). The results indicated that IWM practices, particularly herbicide combinations, significantly improved weed control, crop resistance, yield and economic returns in direct-seeded rice systems.