野外模拟降雨条件下坡面降雨入渗、产流试验研究

Field Experiment on Hillslope Rainfall Infiltration and Runoff under Simulated Rainfall Conditions

利用野外模拟降雨试验,研究了植被类型、降雨强度、地表结皮、覆盖杂草等对荒草地和裸地降雨入渗、产流的影响。结果表明:裸地因降雨易产生地表结皮,产流时间主要取决于降雨强度,两者的关系可用幂函数描述,达显著水平;荒草地由于植被覆盖度较高,产流时间主要取决于土壤初始含水量,两者的关系可用线性公式描述,达极显著水平;与裸地相比,荒草地能延缓产流,并有效拦蓄径流;裸地形成地表结皮后,产流提前,平均入渗率降低,但坡面覆盖杂草(尤其是坡中下部覆盖杂草)能有效拦蓄径流、延缓产流、增加入渗,并促进土壤水分向深层的运移。

The effects of vegetation type, rainfall intensity, surface crust, and weed cover on rainfall infiltration and runoff on grassland and bare land were studied under simulated rainfall conditions. The results show that surface crust could easily take place on bare land, so its runoff-yielding time primarily depends on rainfall intensity, and their relationship might be described by a power function. However, runoff-yielding time on grassland with a higher cover ratio primarily depends on initial soil water content, and their relationship might be described by a linear function. Compared with bare land, grassland could delay and intercept runoff effectively. After surface curst was formed on bare land, runoff generation would be earlier and the average infiltration rate would be lower. However, bare land covered with weed, especially in the middle and bottom parts of the hillslope, would delay and intercept runoff, increase infiltrated water, and make soil water move deeper. Moreover, evaporation inhibition after rainfall also has the similar effects.