Qinghai Lake Area Soil Moisture Content And Enrichment Characteristics Research

In this article, as the study area we choose the Jiermeng township, Quanji township and Xihai town of Qinghai lake area. This area located in the cold area of Xizang plateau, and has complex topography, harsh natural environment. By field research, sample collection and laboratory analysis, we studied the variation of soil moisture and characteristics of particle size. we reached the following conclusion:(1) The upper soil layer soil moisture is greater than20%above the depth of0.6m on the flat low grass land of Jiermeng township. The soil moisture is lower in the depth between0.8～1.1m, and exists moderate or severe dry layers. The soils moisture of each sampling sites are showed decreasing trend as the increases of the depth. The more dry layers with the increase of depth.(2) The average soil moisture of0.15m,0.2m,0.3m and0.4m thin soil layer of Quanji township are higher than15%. There are no dry layer exist because of the soil layer is not enough deep.(3) There are rich upper soil moisture in Xihai town, the soil gravity water reaches to0.6m, the average soil moisture reaches to20%. There is a serious shortage of soil waters in the lower soil layer, the average soil moisture is7.0%in the depth from1.1m to2.0m, dry layers thickness reaches to1.1m.(4) The main soil particle contents of Qinghai lake area is coarse silt, and has some characteristics with the depth. The particle size and soil moisture is inversely related. There are highest coarse silt contents in the Jiermeng Township, the average content is36.5%, and there are also higher content of fine sand, very fine sand and fine sand. The main soil particle contents of Quanji township is coarse silt, average particle content is41.3%. There are also a higher contents of very fine sand, clay sand and fine sand, but there are lower content of coarse sand and medium sand. The main soil particle contents of Xihai town is coarse sand, average content is31.4%. There are also a higher contents of very fine sand, clay sand and fine sand, but there are lower content of coarse sand and medium sand. The lower parts of soil particle contents is sand.(5) Qinghai Lake area soil moisture vary widely in each section, has high water contents in upper soil layer, and exists more gravity water. This is caused by the low temperature, long period of soil freezing, evaporation, thin upper soil particle size composition and in recent years increased precipitation of Qinghai Lake area. Lower soil layers coarse particle size composition is the main reason of the lower soil moisture contents.(6) The soil’s medium and severe dry layer development of Qinghai lake area means soil water can not get the supply of atmospheric precipitation below0.8m, soil moisture in a negative balance in normal precipitation years. The negative balance of soil moisture means the loss of rain water through evaporation, transpiration consumption and surface runoff, thus has no excess water through the soil to recharge groundwater, this belong to a abnormal water cycle type.