Water use efficiency and water productivity of aerobic rice under drip irrigation and fertigation system by using daily soil water balance

Rice (Oryza sativa L.) is the staple food crop for more than half of the world's population and influences the livelihoods and economics of several billion people.Asia's food security mostly depends on irrigated lowland rice cultivation practices, which produce three-quarters of all the harvested (Pimentel et al., 2004;Bouman et al., 2005).Lowland irrigated rice requires a lot of water for puddling, transplanting and irrigation.Further, significant water losses occur through seepage, percolation and evaporation.It is estimated that it consumes 3000 to 5000 liters of water to produce one kilogram of rice.In India, the annual per capita availability of water may be reduced to 1340 cubic meters in 2025 and 1140 cubic meters in 2030 (Suhag, 2016).India is already water water-stressed country and is moving towards turning into water scarcity.The declining water availability and increasing cost of water endangers the traditional system of puddled transplanted rice cultivation (Maraseni et al., 2018).This shortage of water is forcing the farmers to adopt water-saving and cost-effective rice cultivation techniques.Addressing these issues requires an integrated approach to soilwater-plant-nutrient management at the plant rooting zone.The introduction of drip irrigation in aerobic rice is one of the watersaving methods of growing rice by direct seeding in unpuddled conditions without standing water and irrigating similarly to other upland cereal crops.The water use studies on aerobic rice cultivation through the daily soil moisture balance method are very precise in applying the irrigation schedule to maintain the field capacity of the crop.