Soil Moisture Characteristics of Different Vegetations in Hilly Region of Loess Plateau in Northwest Shanxi

Various vegetations play important roles in regulating hydrological cycles of terrestrial ecosystems. Four types of vegetation namely Populus simonii forest,Caragana korshinskii forest,grass land and abandoned land in Pianguan county of Shanxi province were chosen as the study sites to measure the soil moisture content in 0 ~ 600cm soil layer respectively,with the objectives to understand the soil moisture content conditions,vertical distributions and variations of different vegetation types in northwest Shanxi. The results were as follows:( 1) In the 0 ~ 600 cm soil layer,the average content of soil moisture of the four vegetations is significantly different( p 0. 05),showed the results of Populus simonii forest grass land abandoned land Caragana korshinskii forest;( 2) In the 0 ~ 600 cm soil layer,the soil moisture content decreases gradually and then goes stable as the soil depth increases. Significant differences of soil moisture content are shown in both the same vegetation type in different depths of soil and different vegetation types in the same depth of soil;( 3) Soil profiles can be divided into four parts based on the actual situation of research plots: variable layers( 0 ~ 100 cm),active layers( 100 ~ 200 cm),sub-active layers( 200 ~ 300 cm),and relatively stable layers( 300 ~ 600 cm). Therefore,selection of appropriate plant species and adoption of vegetation configuration modes which combine tree-grass modes and tree-shrub-grass modes according to the characteristics of changes of soil moisture in this region are of great significance to guide vegetation construction in this region.