地表糙度对径流和产沙影响的室内试验研究

该文通过室内人工模拟降雨的方法，分析了连续降雨过程条件下，不同糙度地表的径流量和产沙量的变化。研究结果表明：人工锄耕的地表，延缓径流的作用较为明显，但这一作用仅发生在降雨初期；随着降雨的进行，不同糙度地表的径流变化规律基本一致，先增加，随后趋于稳定的趋势，但径流总量没有明显变化。同样，人工锄耕的地表，延缓地表的产沙作用强于糙度小的地表，产沙率15°坡面要高于5°坡面，随着降雨的进行，在雨强1.0 mm/min条件下，这一变化更为明显，最终产沙总量变化不大。地表糙度对侵蚀的影响，不仅与降雨持续时间相关，同时与坡度密切相关，并初步证实黄土区地表糙度对侵蚀的影响存在着一定的临界条件。这为揭示地表糙度的本质特征提供了一定的理论依据，同时也可服务于黄土高原坡耕地水土流失的治理和退耕还林(草)工程的实施。

Effects of soil surface roughness on runoff and sediment discharges with laboratory experiments

Based on artificial rainfall simulation experiments, the variation of runoff and sediment were obtained under the condition of the different soil surface roughnesses and the continuous rainfall. Results show that runoff is delayed for the case of the different soil surface roughnesses with the rainfall. The function is relatively obvious to the soil surface with artificial hoe. However, it appears only to the initial rainfall stages. The variation laws of runoff are the same with the rainfall. The runoff increases at the early stages and becomes stabilization gradually. The total runoff amounts do not change notably for the sum of the five rainfall applications. The amounts of sediment at the 15° slope surface are greater than those at the 5° slope surface. The variation is more obviously during the condition of the rainfall density of 1.0 mm/min. The total amounts of sediment do not change obviously with the rainfall. From the above, effects of soil surface roughness on soil erosion have the relationship not only with rainfall duration but also with slope gradient, and the critical conditions to soil surface roughness effect on erosion are approved preliminarily in Loess Plateau. The results would provide theory basis for revealing the nature of roughness, and at the same time, it would serve for harnessing soil and water loess and reclaiming forest and grass from farmland in Loess Plateau.