Subsurface Drip Irrigation for Wet Season Rice Production Under Climatic Variability in India

Of the global cultivable area, 80% is under rain-fed ecosystem which contributes 60% of total food production. Grain yield of rice, that needs sufficient water for production, is affected by the frequent appearance of extreme events like flood and drought under climate change scenarios. There is a need for development of water saving rice production technology as water availability for future agricultural production is going to be limited. The present investigation was carried out to analyze the rainfall variability at Kharagpur, India and to assess the application of drip irrigation as water saving precise irrigation technology to improve rice yield under climatic variability. Meteorological analysis was carried out on past years' data (1977-2008) using a first order Markov chain for the location ‘Kharagpur'. For assessment of drip irrigation, the rice variety ‘Annada' was cultivated on sandy loam soil during the wet season (June – September) of year 2012 using four nitrogen fertilizer levels (0, 50, 75 and 100 kg/ha) and two drip lateral spacings (40 and 60 cm) in a strip-plot design. Probability of occurrence of dry spell length of 3 and 5 days was found to be p ≥ 0.9 and p ≥ 0.5, respectively during the wet season. Among the drip irrigated rice (DIR) treatments, the 40 cm lateral spacing with 75 kg N/ha application through the irrigation water recorded highest grain yield (4264 kg/ha) and total water productivity (0.48 kg/m3). Grain yield of DIR was higher by 6% and lower by 15% as compared to the grain yield of rain-fed direct seeded rice (RFR) and irrigated puddle transplanted rice (PTR), respectively under similar N application level. Also, the N uptake of the DIR increased by 22 and 38% compared to RFR and PTR, respectively. The drip irrigation was effective in increasing the irrigation water productivity to 8.97 kg/m3 from 2.24 kg/m3 recorded in the PTR.