Transplanted rice response to non-chemical weed management in a degraded wetland ecosystem

Rice (Oryza sativa L.) is a staple crop feeding over half of the global population, especially in Asia where it contributes 90% of global production. Weed infestation remains a critical constraint in rice ecosystems, significantly reducing yield. To evaluate the efficacy of non-chemical weed management practices in transplanted rice, a field experiment was conducted at the Wetland Farm of Tamil Nadu Agricultural University, Coimbatore, during rabi 2022 and kharif 2024 seasons. The study assessed growth, physiological traits and yield of rice under 12 weed management strategies arranged in a randomized block design (RBD) with three replications. The treatments included traditional chemical control as a standard treatment for comparison, hand weeding and a range of non-chemical treatments including ITK-based foliar spray (cow urine, lime solution, khadi soap and common salt), dual cropping and incorporation of Azolla, intercropping with dhaincha, rice bran application, rice hull extract, double green manuring, cono-weeding and mycoherbicide applications. The standard chemical control treatment (Butachlor @ 1 kg ha−1 at 3 DAT + Bispyribac sodium @ 25 g ha−1 at 25 DAT – T9) produced the highest grain and straw yield (5427 and 7238 kg−1 ha in rabi 2022 and 5385 and 7189 kg−1 ha in kharif 2024), followed by hand weeding twice (T11). Among the non-chemical treatments, the foliar spray of ITK-based farmers' practice combined with hand weeding (T1) recorded the highest value in growth, physiology and yield followed by dual cropping with Azolla (T5) and cono-weeding (T8). The findings highlights that non-chemical weed management strategies can effectively suppress weeds and sustain rice productivity, offering viable alternatives to herbicide-based approaches.