Abstract:
To explore the soil water holding capacity of Sabina przewalskii forest land is of great significance to the study of soil water movement,solute transport and physiological water use of forest and grass vegetation in Alpine mountainous areas. In this study,the soil of 0~60 cm in the Sabina przewalskii field is taken as the research object. The centrifugal method is used to obtain the soil moisture content of different soil depths under the specified rotation speed. Four empirical models,Gardner,van Genuchten,Broods Corey and Fredlund Xing,are used to fit the measured water content and soil matrix potential,and the fitted soil water characteristic curve is obtained. The results show that:(1) van Genuchten and Fredlund Xing models have the highest fitting accuracy and the difference is small. Therefore,both of them can be used as the optimal fitting models for Sabina przewalskii forestland,but the physical significance of the parameters of Fredlund Xing model is clearer.(2) The soil water holding capacity of Sabina przewalskii forestland is different in different soil depths,and the difference is more significant with the decrease in soil moisture content. Among them,40~50 cm soil layer can still release more water under high suction(>0.1 MPa),maintain high water content,and have relatively strong water holding capacity. However,0~10 cm soil layer releases less water,has low water content and relatively weak water holding capacity. In addition,the soil water holding capacity of 30~60 cm soil layer is better than that of 0~30 cm soil layer,so 30~60 cm soil layer is the main water conservation layer of Sabina przewalskii forestland.