Soil Moisture Dynamic Under Different Land Uses In The Typical Karst Peak-cluster Depression Area, Northwest Guangxi Autonomous Region

The Typical Karst Peak-cluster Depression Area of Northwest Guangxi Autonomous Region is an Area that is droughty, absent soil and agricultural Eco-environment deterioration. Precipitation is only source of plant using water, plant absorb precipitation mainly through redistribution of precipitation' time and space in soil. The unique hydrology of the Typical Karst Peak-cluster Depression Area determine the much more depending of plant growth on the modulation and redistribution of water by the soil in this area, so, this paper is just about the studies on the dynamics of soil water under different land uses and its main related factors in the whole growth season.On the basis of the research of the fixed location about the Typical Karst Peak-cluster Depression Area of Northwest Guangxi Autonomous Region, applying the hydrology of Karst, Soil Physics, Ecology and Agricultural Systematic Engineering, the Dynamic rules of the soil water of all kinds of vegetation types in the whole growth season was revealed, and the circulation of soil water, the balance of soil water were evaluated and analyzed. The results are as follows:1. The space-time characteristics of the Soil water in The Typical Karst Peak-cluster Depression Area of Northwest Guangxi Autonomous Region: In whole growth season (may- September), Losses of moisture in soil were in May and September and storages of moisture in soil were in June, July and August in all kinds of vegetation types; Except Guancong, on the sloping field, the soil water content fluctuate drastically in layers of 0-10cm and 10-20cm; In the depression, with the increasing depth of the soil, the soil is divided into activing layer, activing layer correspondingly, steadily layer.2. The soil water change in all kinds of vegetation types is consistent with seasonal rule of Precipitation. The soil water is affected remarkably by air temperature, air humidity and sun radiation. The soil trait, the vegetation types, and the mode of land uses also affect the soil moisture.3. The circulation of soil water of all kinds of vegetation types is affected by the amount of rainfall in those years. The difference of the soil water among all kinds of vegetation types is due to the difference of location and vegetation growth.