Water productivity and profitability of hybrid rice as influenced by irrigation and nitrogen management under system of rice intensification

Abstract

An experiment was conducted during rainy season of 2014 and 2015 at Varanasi to standardize water saving and economical nitrogen management options for hybrid rice (cv. PHB 71) under system of rice intensification (SRI). The experiment was laid-out in split-plot design with 3 irrigation schedules (irrigation at 2-day after disappearance of ponded water (DADPW), 5 DADPW and 8 DADPW) in main plots and 5 nitrogen management options (100% recommended dose of nitrogen i.e. RDN 150 kg N ha−1), 100% RDN + S. aculeata as co-culture, 75% RDN + S. aculeata as co-culture, 100% RDN + BGA and 75% RDN + BGA in sub-plots with 3 replications. The irrigation application with 5±2 cm at 2 DADPW resulted in higher plant height (126 cm), leaf-area index (LAI) (5.1), dry matter accumulation (DMA) (71.8 g hill−1), effective tillers m−2 (257), grains panicle−1 (187), 1000-grain weight (24.7 g), grain yield (6.67 t ha−1) of rice over 8 DADPW but remained statistically at par with 5 DADPW. Among nitrogen management options, application of 100% RDN + BGA (12 kg powder ha−1) resulted in increase in plant height (129 cm), LAI (5.22), DMA (71.4 g hill−1), effective tillers m−2 (262), grains panicle−1 (190), 1000-grain weight, (24.8g), grain yield (6.78 t ha−1), straw yield (8.69 t ha−1), B-C ratio (2.08). The highest water productivity (5.07 kg lit−1 ha−1) and B-C ratio (1.99) of rice was recorded when irrigated at 8 DADPW and 5 DADPW, respectively.