Soil water distribution and water restoration in dried soil layer at Jiangxigou in southern Qinghai Lake

Through measuring the soil moisture content of the grassland at Jiangxigou in the southern of Qinghai Lake,the problems of the soil moisture content,water cycle and so on are studied in this paper.In 2009,it is a wet year in the region,but dried soil layer occurred still in the year.The gravity water distribution depth in grass soil reached 0.7 m in the wet year.When eighteen months passed,dried soil layer disappeared.The annual precipitation of recovery of dried soil layer is over 400 mm.The water move of this region is slower than that of loess plateau,and water recovery in dried soil layer was so slow that soil water assembles in the upper layers.The depth of water recovery is small.The reason above is that freezing period is long and evaporation process is weak.In the region,development of dried soil layer in the region indicates that soil moisture cannot recharge groundwater through the infiltration,which belongs to the type of abnormal water cycle.The existence of dried soil layer in the region shows that soil water input is less than output,that is,soil water balance is the negative.There is the character of positive equilibrium unless the annual precipitation is more than 400 mm.