中文摘要：

探讨我国干旱半干旱地区大气降水在土壤剖面中的时空分布特征将为西鄂尔多斯荒漠退化生态系统恢复和维持提供科学依据．本研究利用氘同位素技术研究了内蒙古西鄂尔多斯荒漠的大气降水、土壤水、地下水中的氘同位素值（8D），运用二元线性混合模型计算降水对各层土壤水的贡献率，并结合土壤含水量分析了不同降水条件下土壤剖面各层土壤水8D的时空分布特征．结果表明：雨后9d内，小雨（0-10mm）影响0～10cm土壤含水量和土壤水8D值，对表层土壤（0～10cm）的贡献率在30．3％～87．9％；中雨（10～20mm）影响0～40em土壤含水量和土壤水6D值，对0～40cm土壤水的贡献率为28．2％～80．8％；大雨（20～30mm）和特大暴雨（〉30mm）影响0～100cm土壤含水量和土壤水6D值．降水对100～150em深层土壤水8D值影响不显著．西鄂尔多斯荒漠土壤水8D介于大气降水6D与地下水8D之间，表明西鄂尔多斯荒漠土壤水主要来源于大气降水与地下水．在同一降水强度下，表层土壤水（0-10cm）受降水的直接影响显著，随着土壤深度的增加，土壤水6D变化幅度降低，100～150cm深层土壤水8D基本趋于稳定．降水强度越大，对土壤水8D影响的时间越长，影响的土壤深度也越深．

英文摘要：

Understanding the soil-profile temporal and spatial distribution of rainwater in arid and semiarid regions provides a scientific basis for the restoration and maintenance of degraded desert ecosystems in the West Ordos Desert of Inner Mongolia, China. In this study, the deuterium isotope （δD） value of rainwater, soil water, and groundwater were examined in the West Ordos Desert. The contribution of precipitation to soil water in each layer of the soil profile was calculated with two-end linear mixed model. In addition, the temporal and spatial distribution of δD of soil water in the soil profile was analyzed under different-intensity precipitation. The results showed that small rainfall events （0-10 mm） affected the soil moisture and the δD value of soil water in surface soil （0- 10 cm）. About 30.3% to 87.9% of rainwater was kept in surface soil for nine days following the rainfall event. Medium rainfall events （10-20 mm） influenced the soil moisture and the δD value of soil water at soil depth of 0-40 cm. About 28.2% to 80.8% of rainwater was kept in soil layer of 0-40 cm for nine days following the medium rainfall event. Large （20-30 mm） and extremely large （〉30 mm） rainfall events considerably influenced the soil moisture and δD value of soil water in each of the soil layers, except for the 100-150 cm layer. The δD value of soil water was between those δD values of rainwater and groundwater, which suggested that precipitation and groundwater were the sources of soil water in the West Ordos Desert. Under the same intensity rainfall, the δD value of surface soil water （0-10 cm） was directly affected by D of rainwater. With increasing soil depth, the variation of soil water δD decreased, and the soil water of 100-150 cm kept stable. With increasing intensity of precipitation, the influence of precipitation on soil water ~D lasted for a lon- ger duration and occurred at a deeper soil depth.