关键词: 科尔沁沙地, 地下水位, 不同地貌类型, 沙丘-草甸相间地区, 降雨的响应

Abstract: Based on the soil and ecological survey and data of rainfall and groundwater level,this paper comparatively analyzed the response relationship between groundwater level and rainfall in different landform types(including mobile dunes,semi-fixed dunes,fixed dunes,woodland at dune site,high coverage meadow,plough of meadow and low coverage meadow) in the dune-meadow alternate region in Horqin,Inner Mongolia,China,the impact of an identified rainfall on the groundwater levels in different landform types,and impact of different rainfall to the groundwater levels in an identified landform type. The results show as follows:(1) the rainfall events less than 13 mm had no impact on the groundwater level in the mobile and semi-fixed dunes,and the rainfall events less than 4 mm had no effect on the groundwater level in the fixed dune and woodland at dune site;in dune area,the underground water level increased with the increase of the vegetation coverage,and the lag time of the rise of underground water level declined with the increase of the vegetation coverage;(2) after a larger rainfall event,the groundwater level of mobile and semi-fixed dunes had a clear downward trend;however,if the rainfall intensity reached 40 mm·h^-1 in mobile dunes or 22 mm·h^-1 in semi-fixed dunes,the groundwater level might occur mutation;(3) if the previous rainfall was effective rain,and the two rainfalls were within a short interval, the previous rainfall would influence the dry sand bed thickness and soil moisture,then promote the recharge of groundwater with rain,and this kind of promotion was more obvious in dune than in meadow;(4) in meadow area,rainfall intensity greatly influenced the groundwater level which was obviously affected by the seasonal and surface vegetation coverage,and the fluctuation of groundwater level was more significant after rain; (5) because of the shallow depth of the groundwater level in meadow area,capillary water was close to or even extended to the ground;in some small rainfall events,the groundwater level would rise higher than that in some greater rainfall events;(6) plough had a significant negative effect on the recharge and storage of groundwater in the meadow of arid area. Plough and over grazing had an obvious negative effect on the conservation of groundwater after rain in the meadow of arid area,but this article cannot give the quantization result of rational exploitation, which needs supplement and perfection of data. In addition,afforestation and maintenance of high coverage of surface vegetation is conducive to the storage of groundwater and rainfall recharge of groundwater,and giving priority to ecological management in dune-meadow transition zone near the lake and meadow whose groundwater discharge is weak has more advantages to the storage of shallow groundwater.

Key words: Horqin sandy land, groundwater level, different landforms, alternate area of dune and meadow, response of rainfall