Bio-efficacy of carfentrazone-ethyl against broad-leaved weeds and its effect on direct-seeded rice productivity and nutrient uptake

AbstractFarmers are preferring direct-seeded rice (DSR) than traditional transplanted rice cultivation practices due to water scarcity and agricultural labors shortage. However, weeds are a major challenge in DSR production systems. A field experiment was conducted at the Research farm of Bidhan Chandra Krishi Vishwavidyalaya, West Bengal, India ((22°97' N, 88°44' E, and 9.75 m above MSL) during Kharif seasons of 2022 and 2023 to evaluate the efficacy of varying doses of carfentrazone-ethyl in comparison with oxyfluorfen and hand weeding on diversified weed flora and assess their effect on growth, nutrient uptake and yield of direct-seeded rice for identifying a suitable herbicide and its optimum dose for sustainable direct-seeded rice production. There were seven treatments, viz. four doses of carfentrazone-ethyl 40% DF (carfentrazone-ethyl) 15, 20, 25 and 30 g/ha; oxyfluorfen 23.5% EC (oxyfluorfen) 240 g/ha; hand weeding twice at 20 and 40 days after seeding (DAS) and weedy check. A randomized complete block design replicated thrice was used. Among the tested herbicides, carfentrazone-ethyl 30 g/ha effectively reduced the total weed density by 55.08% and 53.83% at 30 and 45 days after seeding (DAS), respectively and biomass of broad-leaved weeds and annual sedges by 81.22% and 77.31% at 30 and 45 DAS, respectively, compared to control. The carfentrazone-ethyl 30 g/ha recorded highest rice grain yield too and may be considered as the best treatment for managing weeds, particularly when the broad-leaved weeds and sedges are predominant, in direct-seeded rice.