Qinghai And Hubei, Side Gangcha County Soil Water Environment

The Qinghai Lake Basin is one of the ecological and environmental vulnerable regions in China. There are many severe ecological and environmental issues with the tendency of climate change in this area, such as the increase of number of populations and live stocks, the acreage for Qinghai Lake declined, the deteriorated grassland, the land desertification, the decrease of biological diversities and so on. This will affect local ecological security and economy and society's sustainable development. The Qinghai Lake is also an obvious calefacient region in the world. It is necessary to pay great attention to ecological and environmental influence due to global wanning. Furthermore, human activity is gradually serious, so the problem of ecology and environment will face great challenges.The paper use data of soil moisture content of grassland in the years of 2009 and 2010 in north of the Qinghai Lake and the record of temperature and precipitation at the Qinghai Lake Basin in recently 50 years from change of soil moisture content under the tendency of global warming point of view. The characteristics of soil moisture content, the exist of dried soil layer and its recovery conditions, the feature of soil water movement, soil water movement and vegetation suitable for development are studied., Which will give great scientific basement to construction of ecology and environment in the Qinghai Lake Basin. Mainly conclusions are as follows:(1)The bulk water have already moved to the place lm below the surface of soil profile after rainy season nine month in much precipitation year in 2010. The average soil moisture 0.7～lm below the surface is 5.7% more than that in August,2009, and that in 0.7～1.3m is 11.4%,0～1.3m is 9.7% in Shaliu Revier Town. The average soil moisture 0.7～1m below the surface is 3% more than that in August,2009, and that 1.1～1.3m is 7.8%,0.7～1.3m is 5.8%,0-1.3m is 4.9% in Jier Meng Rural Area.(2)It is very common that dried soil layer developed in north Qinghai Lake. The beginning growth depth of dried soil layer is 0.7～0.8m in Shaliu Revier Town, and that is 0.9～1.1m in Jier Meng Rural Area. The range of variation of soil moisture content is from5% to 11% in the depth form the beginning of the exist of dried soil layer 0.4m above the bottom of soil profile, which the mild dried soil layer and moderate dried soil layer developed. The particle size is become remarkable rough at 0.4m approach to the bottom of the soil profile. Which the moderate dried soil layer developed. (3)It is very common that dried soil layer developed below 0.7m in north of the Qinghai Lake during the precipitation normal years, and the pay is greater than income, we call that phenomenon is negative balance. Also soil moisture content in each layer is recovered in certain extent, but dried soil layer in Jier Meng Rural Area more common than that in Shaliu Revier Town, which relative much to local climatic conditons.(4)It is very common that dried soil layer developed in north of the Qinghai Lake on the conditions of less than 400mm annual precipitation. Dried soil layer will recover under the conditions of 420mm annual precipitation, so the recovery of dried soil layer will need the annual precipitation about 420mm.(5)Soil particle size in the northth of the Qinghai Lake is silty soils, soil porosity varied between 50% and 55%, and soil thickness varied between 0.8m and 1.6m. It's so thin and the adjustment ability of soil reservoir is poor, and that will easily result in dried soil layer.(6)The tendency of annual and seasonal temperature is increase in the Qinghai Lake Basin, especially in past several years. The coefficient of variation of spring, autumn and winter are all big. However, the coefficient of variation of annual and summer precipitation are small, but the decrease trend of summer precipitation is obvious in recent 20years. There will also have dried soil layer in next 8～10a in north of the Qinghai Lake. Grassland is rare in water, which has something to do with successive rare in water in soil in recent years.(7)Soil moisture content have great difference from head piece to underpart of soil profile in north of the Qinghai Lake. Soil water movement is very slow, and there are some bulk water lingers at the top of soil.It is better to develop grass seed consuming less water in plains near lake, and not to plant shrubs or trees.