我国干旱地区土地资源丰富，水资源短缺和土壤盐碱化是灌溉农业发展的主要障碍，在灌区开展井渠结合膜下滴灌，可节水控盐，具有重要的实际应用价值。本研究以井渠结合膜下滴灌为背景，研究干旱灌区井渠结合的高效用水机理和水分转化特征，探讨膜下滴灌在局部尺度、田块尺度和区域尺度土壤盐分的运动规律、相互关系和盐分去向，提出长时间土壤和地下水盐分的多尺度嵌套耦合数值模型，根据理论分析和野外实验，探讨表层土壤、浅层地下水和深层地下水之间的水盐交换特征和演变规律，为干旱区井渠结合膜下滴灌的持续发展提供理论支持。

The land resource is abundant in arid region of China, and the main obstacles for irrigating agriculture in this region are the water resource shortage and soil salinity. The mulched drip irrigation under the conjunctive use of groundwater and surface water in arid irrigation district has the advantages of water saving and soil salinity control, and it is shown as a valuable and great potential irrigation method. This work explores the water saving mechanism and water exchange regularities between groundwater and surface water under mulched drip irrigation in arid irrigation district. The salt exchange at local scale, field scale and regional scale will be discussed and the final bearing area will be analysed. A multi-scale numerical model for the long term prediction of soil salinity will be developed. The salt transport between different scales and the salinity evolution patterns will be discussed based on multi-scale modeling and field experiment. This work will provide the theoretical base for the analysis of the sustainability of mulched drip irrigation under conjunctive use of groundwater and surface water in arid region.