Enhancing Water Use Efficiency for Food Security and Sustainable Environment in South Asia

The future of Indian agriculture is at risk due to constantly depleting aquifers and increasing pressure on surface and ground water resources. In this chapter, we have synthesized the information on different water management approaches, irrigation scheduling, and the impact of conservation agriculture (CA) based crop management practices on irrigation water saving and water productivity (WP) in both rainfed and irrigated ecosystems. A single approach for irrigation management will not be capable to achieve the approaching challenge of generating ‘More Crop Per Drop and also contributing to the ‘Jal Shakti’ mission of the Government of India. Integration of irrigation technologies (water-saving methods, irrigation scheduling approaches, etc.) with new resource conservation technologies are essentially required to harness the full potential of available irrigation water for achieving higher WP and profitability in dominant cereal-based systems on a sustainable basis. Improved irrigation management practices (amount and time) and methods (micro-irrigation, surface, sub-surface drip) based on real-time monitoring of crop-soil moisture are required to increase the WP by efficiently managing the water resources. Studies showed that CA-based practices are gaining momentum in India and elsewhere and have helped improving resource use efficiency including WP. Limited studies on water management practices under CA have demonstrated complementarities of coupling these practices for conserving the soil water by reducing evaporation, and improved crop yields, which ultimately increased the WP. In the future, we got to increment logical knowledge of the impacts of agronomic practices on WP over different soil types and agro-climatic situations to enhance WP of cropping system as a whole by using micro-irrigation methods coupled with irrigation automation techniques. With an increase of salt concentration within the water, declining grain yields and weakening soil health have been broadly observed. Similarly, there is a need to plan long-term irrigation expansion policies using poor-quality saline/sodic ground waters to sustain yields and increase the WP.