关键词: 防护林, 土壤水分, 动态变化, 节水型农业

Abstract: In the arid and semi-arid areas of the west part of Northeastern China.one of the key factors to agriculture and animal husbandry is about water. The regularity of soil moisture dymamics in this area could be characterized by a dry spring in May and June, a water-sufficient period from Jul. to Sept. (no significant difference between soil layers), and a water-retaining Period from Oct. to Feb. of the next year.The establishment of shelterbelts decreased transpiration and consequently increased soil moisture; but the effect varied with it's distance from the belt, and there exist evidently an optimal Zone and a minimum Zone in Soil moisture content. On this basis, the agricultural planting patterns could be regulated to utilize soil water more efficiently, which provided one approach to watersaving agriculture.It reached the conclusion that the type of shelterbelts, height of trees, composition of tree species, and distances between two belts were all important factors affecting soil moisture distribution in the shelter net, which provided scientific basis to the optimization of shceltfrbelt system.

Key words: Shelterbelt, Soil moisture, Dynamics, Water-saving agriculture