An integrated strategy for improving water use efficiency by understanding physiological mechanisms of crops responding to water deficit: Present and prospect

Water use efficiency (WUE), defined as the ratio of plant carbon gain to water use in various spatio-temporal scales, is a complex indicator of physiological, agronomic, and engineering processes, as well as management practices. Improving WUE at different scales is an important pathway to combat the global water shortage and ensure food supply, which requires both understanding the physiological mechanisms of crop responding and adapting to water deficit, and innovating field water management technologies. We reviewed advances and perspectives in the research field related to improving WUE at different scales and discussed the key obstacles and possible solutions in practice. A water-saving, quality-improving, high-efficient water use strategy was proposed and an integrative management approach making use of diverse advanced WUE improving technologies was constructed. Both the water use strategy and integrative approach were developed based on physiological mechanisms of crop responding to water deficit, crop life water requirements, precision irrigation water management according to real-time monitoring of crop responses to water deficit, as well as crop water-yield-quality models. The review was expected to provide a reference for researchers in the water management communities and boost sustainable development of water-saving agriculture in water shortage areas. •Appropriate water deficit at right time could improve crop yield, quality, and water use efficiency (WUE).•Physiological mechanisms of crop responses to water deficit provide a foundation for improving field WUE.•Accurate monitoring and diagnosis of crop water deficit are necessary to implement efficient water management practices.•An irrigation strategy for regulating yield and quality is introduced based on the quantitative models.•An integrative approach for water-saving, quality-improving, and high-efficient water use has been developed.