Studies On Soil Water Content Dynamic Varying Of Typic Castanozem In Leymus Chinensis Steppe In Inner Mongolia

Soil water is one of the most important ecosystem factors. It has an important influence to the ecosystem. Systematic study on the dynamic feature and rule of variation of soil water is helpful for the establishment of measuring method and predication model, especially under the ground of global climate change including the temperature of atmosphere increasing and precipitation increasing.This is a study on the variation and trend of soil content based on the data of Baiyinxile region in Leymus chinensis steppe and the data of observation on the castanozem of the semi-arid region for 10 years. Based on this, this study has analyzed the temporal nature, the temporal feature of yearly variation and the monthly feature of temporal variation of moisture in Typical Castanozem. The following is the main result.1. The differentiation of soil water content between enclosure and non- enclosure increased by years. And that the soil water content in enclosure is higher than that of non- enclosure, in the end it tends to stability. Transformation of soil water content in the layer of 0-30cm is quickly, and under the layer of 30cm is slightly, but under the layer of 70cm is hardly. Transformation feature of soil water content of vertical profile is greatly with the depth accretion. The soil water content in the depth of 0-30cm is higher and is different with months and years, then under the depth of 30cm decrease obviously.2. The soil content dynamic of surface can be divided into three stages: dry and stable stage (May); content varying stage (June to middle of August) and dry stage. The soil content decreases slowly to a lowest point at the middle of June, then increase to most until the middle of August. After the end of August, the soil content decrease to level of middle of June. But soil m content increases with the plant coverage increase.3. Grazing can greatly decrease the soil content in the 0~20cm layer especially the more moist season of spring and rainy season. Long-term over grazing will cause the soil tending toward arid situation.