科尔沁沙地沙丘-草甸区土壤水、地下水对降雨的响应

Response of soil moisture and groundwater to rainfall in Horqin sandy land with sand-meadow land features

依据野外观测数据,研究了科尔沁沙地沙丘、草甸两种地貌类型区土壤含水率以及地下水位对降雨的响应规律。结果表明:(1)沙丘表层0-20cm的土壤含水率在降雨开始后20min就基本能够达到最大值,此后开始减小,水分不断向下运移,最大可引起次表层(20-60cm)土壤水分发生一定变化,但不会引起剖面更深层位土壤含水率的变化;2009年丰水期沙丘地下水位变动趋势为总体抬升,但受到降雨及其他因素影响产生一定波动,但影响幅度较小;(2)就草甸地而言,即使是很小的降雨量也会引起草甸地较深层位土壤含水率的变化,雨后草甸地土壤剖面受降雨影响最大的层位是20-40cm,而同时段40-80cm处的土壤含水率波动较小。草甸地地下水位波动大于沙丘,较小的降水也会引起草甸地地下水位的迅速上升,上升持续时间短,而后立即转入下降,属陡涨陡落型。研究成果对沙地的生态保护具有一定的指导作用。

Based on the field observed data,the influences of rainfall on soil moisture of different profiles and groundwater on the sandy dune and meadow land in Horqin sandy land were analyzed.The results indicated that：（1）The 0-20cm top soil moisture of sandy dunes was saturated after 20min-rainfall,and it tended to reduce and infiltrated downward,which can influence the 20-60cm soil moisture content,but had little inpact on deeper soil profile.The water table of sandy dunes presented rising trend in wet period of 2009,and had weak fluctuations as affected by other factors.（2） For meadow land,the deeper soil moisture can be changed by a little rainfall,and rainfall had the largest influence on the profile located at 20 to 40cm,however had little impact on the 40 to 80cm profile.The water table in meadow land fluctuated noticeably than sandy dune,which can be lifted by little rainfall,and the duration is short,then immediately transferred to decline trend.The study can be used to environment protection in sandy dunes of interest.