Crop establishment method and irrigation schedule effect on water productivity, quality, economics and energetics of aerobic direct-seeded rice (Oryza sativa L.)

Rice is cultivated through transplanting of seedling in submerged field which is a cumbersome, labour intensive and water-guzzling practice. A field experiment was conducted to study the effect of crop establishment methods and irrigation schedules on water productivity, economics and energetics of aerobic direct-seeded rice at Punjab Agricultural University, Ludhiana, India, during Kharif 2012-2013. The experiment was laid out in split plot design, keeping combinations of two tillage system (no-tillage and conventional tillage) and two methods of sowing (uni-directional and bi-directional) in main plots and four irrigation schedule [(30, 45, 60 and 75 mm CPE (cumulative pan evaporation)] in sub plots. Aerobic direct-seeded rice sown after conventional tillage gave significantly higher grain yield than no-till with 15.4 % higher water expense efficiency. The energy gain and net monetary returns were 13.2 and 21.2 % higher in conventional sown crop than no-till, respectively. Bi-directional sowing resulted in 26.5 % higher grain yield than uni-directional with no effect on quality traits of grains. The net energy gain and net monetary returns were 26.5 thousands MJ/ha and 125.3 $/ha higher from bi-directional sown crop than uni-directional sown crop. Crop irrigated at 30 mm CPE schedule resulted in significantly higher grain yield than that irrigated at 45, 60 and 75 mm CPE. The energy gain, energy use efficiency and net returns were also maximum at 30 CPE schedule than at 45, 60 or 75 CPE. However, brown, milled and head rice recoveries were statistically at par between irrigation scheduling at 30 and 45 mm CPE but significantly better than 60 and 75 mm CPE. Bi-directional sowing with conventional tillage and irrigation at 30 CPE is an energy efficient and economical viable technique for direct-seeded rice.