Abstract: Water security is the foundation of food security,and the coordinated utilization of multiple water sources in farmland with scarce fresh water and saltaffected soils is of great strategic significance for ensuring national food security.This study analyses the current situation and challenges faced by the utilization of multiple water sources in deficient water resources and saline alkali areas.The high ratio of evaporation to precipitation is the main reason for the formation of saline alkali land,and the scarcity of freshwater resources remains the core issue restricting the utilization of saline alkali land and maintaining the ecological environment.There are significant differences in rainfall resources among different types of saline alkali areas in China,with annual precipitation less than 500mm,and other water sources also have certain differences.Based on the research progress of the theory of five water transformation in agricultural ecosystems,this paper focuses on six aspects: efficient use of plants,efficient utilization of rainfall harvesting,efficient irrigation of surface ponds and ditches,efficient utilization of soil moisture retention and water storage,ecological regulation and utilization of groundwater,and collaborative efficient utilization based on crop life water demand information and the characteristics of multiple water sources in farmland.Key technologies and industries for the development of collaborative utilization of multiple water sources in farmland under future climate change are proposed.This study will provide theoretical reference and technical support for the coordinated utilization of multiple water sources in the deficient water and salinealkali areas.

Key words: Multiple Water Resources, Collaborative Utilization, Efficient Water Utilization, Water Resources Deficient, Saline Alkali Areas