Effect of irrigation scheduling and water stress management on yield, nutrient uptake and profitability of wet-direct seeded rice (Oryza sativa L.) under puddled conditions

A field study was carried out at V.O.C Agricultural College and Research Institute, Killikulam, during the early Kar season of 2021-2022 to assess how different irrigation schedules and water stress management strategies influence profitability and nutrient uptake in direct-seeded rice (Oryza sativa L.) under puddled conditions. The experiment followed a split-plot design with three replications, where the main plots consisted of four irrigation treatments: Alternate wetting and drying (AWD), Irrigation based on the IW/CPE ratio, Water depletion of 15 cm using a field water tube (FWT) and Continuous flooding (Control). The subplots included four water stress management practices: Seed treatment with 1 % Pink pigmented facultative methylotrophs (PPFM) and 1 % foliar spray at critical growth stages, foliar application of paclobutrazol (50 ppm) at critical growth stages, seed treatment with arbuscular mycorrhizal (AM) fungi and soil application at 100 g m-2 and control. The findings revealed that continuous flooding combined with 1 % PPFM application resulted in the highest grain yield (7.6 t ha-1), straw yield (8.3 t ha-1), nitrogen uptake (110.3 kg ha-1), potassium uptake (125.7 kg ha-1), net profitability (₹87950 ha-1) and a benefit-cost ratio of 3.07, which was statistically comparable to the AWD method with 1 % PPFM application. These results suggest that AWD with 1 % PPFM application at critical stages is a viable alternative to continuous flooding for efficient water usage and managing water stress in direct-seeded rice.