Agronomic Practices to Enhance Nutrient Acquisition, Grain Quality, Resource-Use Efficiency in Direct- Seeded Aerobic Rice in Eastern India

Abstract

Aim: Rice (Oryza sativa L.) is mainly grown in the rainy season in eastern India on rainfed uplands with a low average productivity of 1.0-1.4 t ha-1. Erratic rainfall leading to moisture stress and poor cultivation practices are the key reasons for low yields and rice grain quality in the area. Hence, the current study was designed to investigate the effects of irrigation scheduling, soil adjuvant and sowing methods on yield, grain quality and resource-use efficiency in aerobic rice.
 Methodology: The experiment was conducted in a three-time replicated split-plot design during rainy-season of 2016 on a sandy loam soil in Eastern India. Treatments included 8 combinations of 4-irrigation schedules, viz., irrigation at IW/CPE 0.9, 1.2, 1.5 and no-irrigation (rainfed) and 2-soil adjutants (soil adjuvant applied and no-soil adjuvant) assigned to main-plots, and 2-planting methods (conventional dry seeding at 20 cm row spacing and spot-sowing (dibbling of 4-seeds hill-1 at 20×15 cm interval) assigned to sub-plots.
 Results: Irrigation at IW/CPE 1.5 increased grain yield by 37.3% over rainfed crop, 23% over crop irrigated at IW/CPE 0.9 and 13.5% over IW/CPE 1.2. Grain quality parameters were also best, in crop watered at IW/CPE 1.5. Net return, B: C ratio, net energy output, production efficiency (PE) and monetary efficiency (ME) were significantly greater with irrigation at IW/CPE 1.5 compared to other irrigation schedules. Spot-sowing proved superior to conventional drilling of seeds exhibiting about 7% improvement in grain yield and water-use efficiency (WUE). Effect of soil adjuvant application was not significant.
 Interpretation: This study emphatically demonstrated that aerobic rice should be spot-sown and irrigated at IW/CPE 1.5, for obtaining higher yield with better grain quality. The findings are useful for aerobic rice production in eastern India and adjoining sub-humid regions.