通过对青海湖南侧江西沟草地土壤含水量的测定,研究了土壤水分含量、运移和土壤干层水分恢复等问题.2009年该区降水较多,导致2010年7月草地土壤重力水分布深度达到了0.7m左右,但仍有干层存在.经过18个月的水分入渗,在2010年11月土壤干层基本消失,干层恢复的年降水量要大于400mm.该区土壤水分比黄土高原运移缓慢,干层恢复较为缓慢,土壤水分恢复的深度小,水分聚集在土壤的上部,这些特点是该区冻结期较长和蒸发作用较弱造成的.江西沟土壤干层的发育表明该区正常年大气降水一般不能通过土壤入渗补给地下水,属于异常水分循环类型.该区土壤干层的存在指示在降水正常年土壤水分具有负平衡的特点,在年降水量大于400mm的条件下具有正平衡的特点.%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 ram. 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.
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