雨强和坡度对裸地径流颗粒物及磷素流失的影响

采用人工模拟降雨的方法，研究了不同雨强（0~100mm/h）和坡度（0°~10°）条件下，北方砂壤土裸地降雨径流中颗粒物（SS）、总磷（TP）、颗粒态磷（PP）的流失量及径流污染物之间的相关关系，并分析了雨强和坡度对污染物流失量的影响.研究结果表明，雨强和坡度越大，SS和TP流失量越大；径流中SS与TP、TP与PP的单位面积流失量呈显著线性相关关系（R²>0.946）；在实验条件范围内，雨强对颗粒物及磷素流失量的影响比坡度更显著；径流中颗粒物及磷素单位面积流失量与雨强、坡度及场降雨径流总量之间均有明显的线性关系，相关系数大于0.911，由于0°裸地和有坡度裸地的下渗及产流情况差异较大，在模拟雨强和坡度对颗粒物及磷素流失量影响时需分别考虑.结果可为我国北方砂壤土裸地径流中颗粒物及磷素单位面积流失量的估算提供计算方法和科学依据.

Influence of rainfall intensity and slope gradient on suspended substance and phosphorus losses in runoff

Artificial simulated rainfall experiments were conducted in this study to investigate the effects of rainfall intensity (30~100mm/h) and slope gradient (0~10°) on suspended substance (SS), total phosphorus (TP) and particulate phosphorus (PP) losses in runoff from bare land in north China. The relationships between SS, TP and PP losses were also studied. The results showed that SS and TP losses increased greatly with the increase of rainfall intensity and slope gradient. There was a significant linear relationship between SS and TP losses, as well as TP and PP losses (R²> 0.946). Rainfall intensity had more intensive influence on SS and P losses than slope gradient in the range of our experimental conditions. There were clear linear relationships between SS, P losses and the rainfall intensity, slope gradient and the total amount of runoff (R²> 0.911). The linear equations of SS, P losses from bare land with and without an incline should be separately simulated because the rainwater infiltration and the runoff generation pathway on 0degree and other slopes were distinctly different. The results provided a calculation method for estimating SS and P losses in runoff from sandy loam soil in north China.