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采用室内模拟降雨研究了不同坡度对土壤坡面产流产沙特征及其养分流失的影响。结果表明:在降雨条件下,初始产流时间随坡度的增加而趋于提前,初始产流时间变化范围为0.63~1.62min,说明坡面产流时间因坡面坡度的增加而缩短。不同坡度条件下径流强度随降雨历时的增加而增加,在降雨历时前20min,径流强度急剧增加,降雨历时20min以后,径流强度增加趋势趋于平稳,径流强度遵循幂函数变化规律;不同坡度条件下入渗强度随降雨历时的增加而降低,在降雨历时前20min,入渗强度急剧降低,降雨历时20min以后,入渗强度降低趋势趋于平稳,坡面入渗强度随时间则呈对数函数变化。不同坡度下径流量均随降雨历时呈“增加—稳定”趋势(单峰曲线,抛物线规律),在整个降雨过程中,径流量随坡度的增加而增加,在0~20min内,径流量随降雨历时的增加陡然上升趋势,20~40min,不同坡度条件下土壤泥沙侵蚀量均达到最大值,40min以后泥沙侵蚀量随降雨历时的增加呈现基本平稳趋势,泥沙侵蚀量中DP,K+,SEP和SEK均随着坡度的增加而增加。不同坡度条件下,泥沙量与侵蚀泥沙中养分的含量均存在不同程度的正相关关系,其中坡面坡度为20°,25°和30°时,侵蚀泥沙养分含量与泥沙流失量间的相关性明显优于其他坡度,说明侵蚀泥沙量的增加会引起泥沙中各种类养分含量的增加效应,而随着坡度的增加,侵蚀泥沙量与侵蚀泥沙中养分的含量并非均显示出更进一步的相关性。
Effects of different slopes on runoff and sediment yield and nutrient loss on soil sloping land were studied by indoor simulated rainfall. The results showed that under the conditions of rainfall, the initial runoff time tended to advance with the increase of slope degree, and the initial runoff time ranged from 0.63 to 1.62 min, indicating that runoff time of runoff slope was shortened due to the increase of slope gradient. Under different slope conditions, the runoff intensity increased with the increase of rainfall duration. The runoff intensity increased sharply in the first 20 min of rainfall duration. After rainfall lasting 20 min, the trend of runoff intensity tended to be steady, and the runoff intensity obeyed the law of power function. Under different slope conditions The infiltration intensity decreased with the increase of rainfall duration. During the first 20 min of rainfall duration, the infiltration intensity decreased sharply. After 20 min of rainfall duration, the infiltration intensity tended to be stable and the infiltration intensity changed logarithmically with time . The runoff at different slopes showed a trend of “increasing-stabilizing” (unimodal curve, parabola law) with rainfall duration. During the whole rainfall, the runoff increased with the increase of slope. Within 0 ~ 20min, the runoff With the increase of rainfall duration, the trend of soil erosion increased sharply. Soil erosion amount reached the maximum under different slope conditions from 20 to 40 minutes. After 40 minutes, the amount of sediment erosion showed a basically steady trend with the increase of rainfall duration. K +, SEP and SEK increased with the increase of slope. Under different slope conditions, there is a positive correlation between the amount of sediment and the nutrient content in the erosion sediment. When the slope of the slope is 20 °, 25 ° and 30 °, the nutrient content of sediment and sediment loss The correlation between them is obviously better than other slopes, which shows that the increase of erosion sediment will cause the increase effect of various nutrients in sediment. With the increase of slope, the content of erosion sediment and the nutrient content of erosion sediment Not all showed further relevance.