黄土丘陵沟壑区不同植被类型次降雨产流产沙特征

在甘肃省定西市安家沟小流域以径流小区为研究对象，利用径流场在自然降雨条件下监测所得径流泥沙资料，对不同植被类型的次降雨入渗、产流产沙特征进行了对比研究。结果表明：不同植被类型土壤入渗率均随着雨强的增大线性增大，入渗速率与降雨历时呈幂函数关系。油松林的径流系数（15.97%~19.88%）最大，小麦地（10.91%~17.32%）和沙棘林（9.51%~17.47%）次之，冰草地（4.62%~8.30%）和苜蓿地（6.82%~10.66%）的径流系数最小。径流系数（1%~28%）与降雨量之间符合幂函数关系（P<0.05）。径流含沙量平均值排序依次为小麦地（16.49~22.71 g·L^-1）>苜蓿地（12.66~16.91 g·L^-1）>沙棘林（7.04~11.8 g·L^-1）>油松林（6.95~7.78 g·L^-1）>冰草地（5.53~7.71 g·L^-1）。径流含沙量和土壤侵蚀率均与降雨侵蚀力呈正相关关系（P<0.01），可分别采用线性函数和二次函数进行定量描述。研究成果可为黄土丘陵沟壑区水土保持优化配置提供参考。

Characteristics of Slope Runoff and Sediment of Different Vegetation Types under Individual Rainfall Events in Loess Hilly and Gully Region

The runoff plots of Anjiagou watershed were selected as the research object in Dingxi City,Gansu Province,and the characteristics of rainfall infiltration,runoff and sediment of different vegetation types were studied using the observed data of runoff and sediment under natural rainfall conditions. The results showed that:the infiltration rate of soil under different vegetation types increased linearly with the increase of rain intensity,while the relation between the infiltration rate and the rainfall duration was a power function. The runoff coefficient of pine forest (15.97%~19.88%) was the largest,the wheat field (10.91%~17.32%) and sea buckthorn forest (9.51%~17.47%) the second,the wheatgrass meadow (4.62%~8.30%) and the alfalfa land (6.82%~10.66%)were the smallest. In the meanwhile,the relation between runoff coefficient (1%~28%) and rainfall presented a power function (P<0.05). The order of average sediment concentration was as follow:wheat field (16.49~22.71 g·L^-1) > alfalfa land (12.66~16.91 g·L^-1) > sea buckthorn forest (7.04~11.8 g·L^-1) > pine forest (6.95~7.78 g·L^-1) > wheatgrass meadow(5.53~7.71 g·L^-1). There was a positive correlation between sediment concentration and soil erosion rate and rainfall erosivity (P<0.01),which can be quantified separately by linear function and quadratic function. The results can provide references for optimizing configuration of water and soil conservation in Loess hilly and gully region.