Low-cost inputs for enhancing yield, economics and water productivity of transplanted rice under shallow lowland

Producing robust seedlings in the nursery and transplanting them at the optimal age significantly enhances transplanted rice yield and profitability. Seed priming with appropriate bio-control agents followed by sowing at optimum density in the nursery produces healthy and vigorous seedlings. A field experiment was conducted for two years 2020 and 2021 to evaluate the bio-control agents, seeding density and optimum age of seedlings to achieve the potential yield of transplanted rice under shallow low land. The study employs split-split plot design with three factors: Main plots (seed treatments; S1, pseudomonas @ 10 g/kg of seed; S2, trichoderma @ 10 g/kg of seed and S3, no seed treatment), subplots (seeding density; D1, 40 g/m2, D2, 50 g/m2 and D3, 60 g/m2) and sub-sub plots (age of seedlings at transplanting; A1, 42 days and A2, 21 days). Seed treatment with Trichoderma (NRRI formulation) resulted in the production of seedlings having higher length: biomass ratio (55.0) and an increase in the grain, straw yield and gross return by 14.0, 12.3 and 14.1%, respectively, over the control. Transplanting of young seedlings (21 days) resulted in significantly higher average gross return of `123.7 × 103/ha, B: C ratio (2.09) and economic water productivity (`15.09/m3). The use of 21-day-old seedlings reduced the cost of production of transplanted rice by 10.5% as compared to 42-day-old seedlings. Hence, it is recommended to treat rice seeds with Trichoderma @ 10 g/kg of seed, maintain a low seeding density (40–50 g/m2) at the nursery and transplant 21 old days seedlings for realising yield potential of transplanted rice under shallow lowland.