Influence of irrigation regime and nitrogen management on productivity, nitrogen uptake and water use by rice (Oryza sativa)

Abstract

A field experiment was conducted on deep sandy clay-loam soil (Typic Haplustepts) at New Delhi, during 2002 and 2003 to investigate the effect of irrigation regimes, viz. continuous submergence, 1-day drainage, and 3-day drainage, and integrated nutrient management, viz. the control, 75% N of recommended fertilizer dose (RFD), 100% N of RFD, 150% of RFD, 75% N of RFD out of which 25% N substituted by farmyard manure (FYM), 100% N of RFD out of which 25% N substituted by FYM, 150% N of RFD of which 25% substituted by FYM and 75% N of RFD + biofertilizer, on the productivity of rice (cv. 'Pusa Sugandh 3'). Continuous water submergence increased the maximum plant height, number of tillers, leaf-area index (LAI), dry-matter accumulation, number of panicles, grainslpanicle, panicle length, 1,000-grain weight, and the grain and straw yields, which were statistically superior to 3-day drainage but on a par with those of 1 -day drainage. Continuous water submergence resulted in 9.6- 17.4% higher grain yield than 3-day drainage and 2.7-4.6% higher than I-day drainage. Irrigation and water re- quirement of rice were higher with continuous submergence, whereas irrigation, use efficiency and field water-use efficiency were higher with 3-day drainage. Among the nitrogen treatments, application of 150% N of RFD (25% substituted by FYM) induced the highest growth and yield attributes over other treatments and outyielded 75% N of RFD by giving 21.7%, 75% N of RFD (25% substituted by FYM) by 17.1%, and 75% N of RFD + biofertilizer by 14.1% and 40.4% more grain yield than the control in the first year and 19.8%, 19.9% 12.7% and 42.0% in record year. Highest N uptake was recorded with 150% of N of RFD (25% N substituted by FYM) in biomass. Agronomic- nitrogen efficiency was maximum with I-day drainage and 100 kg Nlha applied through fertilizer. Irrigation-use effi- ciency and field water-use efficiency were higher with 150%fl of RFD (25% N of RFD substituted by FYM). It was concluded that under less availability of water, irrigation may be applied on the basis of 1 -day drainage with 150% N of RFD (25% substituted by FYM).