土壤盐结皮改变表层土壤水力性质，影响土壤水分蒸发，是干旱区水循环中一个重要的影响因素。然而，目前盐结皮土壤水分蒸发机理还尚未探明。本研究从盐晶微结构的角度对盐结皮土壤水分蒸发机理进行研究。（1）开展土柱试验研究盐结皮过程中NaCl盐晶微结构在水平和垂直方向上的变化规律，分析盐晶微结构演变阶段特征；（2）采集自然盐结皮样品，运用体视显微镜和扫描电镜研究自然盐结皮盐晶微结构变化规律，结合盐份组成、土壤粒径、土壤含量、地下水质、地下水位研究自然盐结皮盐晶微结构影响因素；（3）测定自然盐结皮土壤水分蒸发量，结合自然盐结皮盐晶微结构变化规律定量研究盐结皮盐晶微结构对土壤水分蒸发的影响；根据盐晶微结构演变阶段构造阶段函数，增加盐结皮密度，改进盐结皮土壤水分蒸发公式，揭示盐结皮土壤水分蒸发机理。研究结果可为区域水循环模式和陆面模式模拟提供更精确的数值公式和理论依据。

Soil salt crust, changing the hydraulic properties of the surface soil and the soil water evaporation of salt crust, is one of the important factors to influence the water cycle in arid areas. However, the mechanism of soil water evaporation of salt crust is not clear now. This research will study the mechanism of salt-crusted soil water evaporation in the view of the salt crystal microstructure. (1)The horizontal and vertical variation of the sodium chloride crystal microstructure on the soil surface during salt crust will be studied through implementing the experiment of the sandy soil column evaporation, and the characteristics of the salt-crusted evolution of the salt crystal microstructure will be determined. (2)The change of the crystal microstructure of the natural salt crust sampled from the field will be studied using stereoscopic microscopy and scanning electron microscopy(SEM), and the factor, such as salt composition, soil particle size, content of soil, underground water quality,underground water level, that influence the crystal microstructure of the natural salt crust will be researched. (3)The effect of the crystal microstructure of salt crust on the soil water evaporation of the natural salt crust will be studied quantitatively combining with the change rules of the crystal microstructure of the natural salt crust salt.The function of the salt-crusted soil water evaporation will be improved through building the step function of the salt-crusted soil water evaporation according to the evolution stages of the salt crystal microstructure, adding the factor of the salt-crusted density, and the mechanism of the salt crust soil moisture evaporation will be revealed. The results of the study will provide a more accurate numerical equation and theoretical basis for the simulation of regional water cycle and Comprehensive Land Surface Model (CLSM).