Effect of planting methods, irrigation regimes and soil adjuvant on yield attributes, yield, nutrient uptake and economics in aerobic rice (Oryza sativa) in eastern India

A field experiment was carried out in the rice (Oryza sativa L.) dominated area of eastern plateau and hill region of India during kharif 2016 to study the effect of irrigation schedules, planting methods and soil adjuvant on yield attributes, water-use efficiency (WUE), economics and nutrient uptake in aerobic rice. The experiment was laidout in a three-time replicated split-plot design, keeping combinations of 4-irrigation schedules, viz., irrigation at 0.9, 1.2, 1.5 IW: CPE (irrigation water requirement: cumulative pan evaporation) ratio and no-irrigation (rainfed), and 2-soil adjuvants (soil adjuvant applied and no-soil adjuvant) in the main-plots and 2-planting methods-conventional dry seeding at 20 cm row spacing and spot-sowing (dibbling of 4-seeds per hill at 20 × 15 cm), in the sub-plots. Irrigation at 1.5 IW: CPE ratio recorded greater magnitude of all yield attributes like panicles/m2, field grains/panicle and 1, 000-grain weight and enhanced grain yield by 37.3% over rainfed crop, 23% over crop irrigated at IW: CPE ratio 0.9 and 13.5% over IW: CPE ratio 1.2. This irrigation schedule also resulted in the highest net return. However, WUE (water use efficiency) was highest with irrigation at IW: CPE 1.2. Spot-planting significantly improved yield attributes, yield, WUE, net return and nutrient uptake over conventional planting. The increase in grain yield and net returns due to spot-planting was more than 7%.