粤北石漠化地区坡地入渗产流规律试验研究

Experimental Study on Process of Rainfall-Infiltration-Runoff Generation on Rocky Desertification Slope in North of Guangdong Province

在粤北山区石漠化地区的裸地、草坡地和耕地等3种类型土地的坡面上,采用0.3,0.48,0.72,1.08mm/min4种降雨强度进行了36场人工降雨模拟试验。结果表明:在岩溶发育的石漠化地区,受基岩的非均质性因素影响,出流过程均呈现出具有一定波动性质的较为曲折的峰谷相间的特点;初期波动性较大,后渐趋稳定;达到稳定的坡面径流量与雨强之间具有十分明显的线性正相关关系。3种土地利用类型的坡面径流量的增幅随雨强增大而显著增加;增幅最为明显的是裸地。其入渗率虽也随雨强的增加而增加,却在增幅上明显小于前者,其中,裸地的增幅最小,基本上能保持稳定。在土壤前期含水量影响较小的情况下,产流时间均随着雨强的增大而迅速缩短,表现为十分明显的幂函数关系,3种土地利用类型均需达到一定降雨量后才能产流。

Simulated rain is a valid tool to examine soil erosion on sloping land.Experiments under 36 events of simulated rainfall with intensities of 0.3 mm/min,0.48 mm/min,0.72 mm/min and 1.08 mm/min and different duration were carried out on three different types of lands（bare land,grassland and farmland） in typical rocky desertification land slope in northern Guangdong Province.Results show that the runoff processes in different lands have features with the fluctuating nature of the valley and peak due to rock heterogeneity factors.The fluctuation range of initial runoff curve was large.There is a very clear linear relationship between reaching stable surface runoff intensity between the rainfall intensity.Land surface runoff intensites on three kinds of land use types increase with the rise of rainfall intensity.The largest and significant increment of runoff occurs on bare land.Although the infiltration rate also increases with the rise of rainfall intensity,the increment is significantly less than that of runoff;the least increment is observed on bare land,however,the infiltaration basically remains stable.Under the case of less initial soil moisture,the time of flow production rapidly shortens with increase of the rainfall intensity;there is an obvious power function relation between initial soil moisture and rainfall intensity.Surface runoff on three types of land produces when the rainfall amount meets a certain level.