华北山区坡地土壤水分动态实验研究

An experimental study of the dynamic regime of soil water in mountainous slopes in northern China

在北京市怀柔区汤河口镇东台沟坡地径流实验小区上进行人工模拟降雨实验,探索降雨过程中体积土壤含水量和土壤水基质势的动态变化。结果表明:在降雨强度和前期土壤含水量较为稳定以及蒸发微弱等条件下,不同场次降雨过程中土壤水分动态变化时间与降雨强度之间呈现明显的幂函数关系;同一场次降雨过程中,坡地内不同部位不同土壤层次的土壤水分动态变化时间与土壤层次和土层部位相联系。降雨过程中体积土壤含水量和土壤水基质势的动态变化可划分为5个阶段。得出的坡地土壤水特征曲线表明了坡地砂质土壤在含水量较大时土壤吸力较小、含水量减小时土壤吸力迅速增大的水力特性。

In the investigation of the dynamic changes in volumetric soil water content and soil water matrix potential during rainfall processes, artificial rainfall experiments were conducted in sloping fields at Dongtaigou near Tanghekou town in the Huairou district in Beijing. The results indicate that under the conditions of steady rainfall intensity, pre-rainfall soil water content and weak evaporation, obvious exponential function correlativity exists between the time of dynamic changes in soil water content and the rainfall intensity; while during the same precipitation process, interrelationship exists between the time of dynamic changes in soil water and the soil layer and position. Dynamic change process of volumetric soil water content and soil water matrix potential can be divided into five stages. Soil water retention curve indicates that the soil hydraulic characteristics of smaller suction are at higher soil water content, while sharply increasing suction is at decreasing soil water content for sandy soil hydraulic characteristics in the sloping fields.