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Crop water management involves managing water supply and water demand, the purpose of which is to maximize crop water productivity and water use efficiency by minimizing losses. Around 70% of Indian agriculture is dependent on rain fed agriculture, the productivity of which is much lower than in irrigated systems. In the Mandri river catchment, kharif rice occupies around 92% of total cultivated area with existing rice yield at 2161 kg/ha. The current study aims at increasing rice yield levels by identifying suitable rice water management strategies to increase both yield and water productivity. Around 17 management scenarios were run on Aquacrop under both rain fed and irrigated conditions (Drip irrigation). Gross irrigation requirement obtained from Aquacrop was used as an input into WEAP model to model the reliability of the catchment to provide for the paddy water demands under the different management scenarios under irrigation as well as under increase in irrigated land area. Utilisation of existing supply management from water harvesting structures was also examined. The results showed that water productivity was the highest (0.92 kg/m3) under improved weed and mulch management.(30% decrease in weed cover and 50% mulch cover). Using crop water management techniques, the rice yields increased to 3200 kg/ha; however, the reliability of this management system was only around 97-98% under the different WEAP scenarios when irrigation was applied to maintain soil water at field capacity, under no stress conditions. This management strategy can be adopted only by additional usage of the water stored by water harvesting structures.
Keywords: Crop water management, Water productivity, Direct seeded rice, scenarios, Aquacrop
