基金项目:国家自然科学基金项目(51209064); the Asia Facility for China Project "Partnership for research and education in water and ecosystem interactions" (10025990)； 中央高校基本科研业务费专项资金(2010B01014)
Soil and vegetation are two interdependent and important components of SPAC (Soil-Plant-Atemosphere Continium) system. The soil moisture is one of determinants affecting vegetation stability in the sandy land. Through measuring the soil moisture content of the root growth region around Salix psammophila which is the main vegetation in the semi-arid and semi-desert area, the change of soil moisture content in horizontal and vertical directions and the relations of soil moisture content and environmental factors such as sunshine, rainfall and landscape slope position were analyzed. The results show that rain fall increases soil moisture content near the land surface; soil moisture content at 65cm depth is relatively lower; the growth of root reduces the soil water content underneath the plant; interaction exists between soil water content and vegetation root system.