土壤结皮对黑土区坡面产流产沙的影响

土壤结皮对坡面产流形成和侵蚀过程有重要的影响。基于室内人工模拟降雨试验，研究了土壤结皮对黑土区坡面产流产沙的影响。结果表明:土壤结皮促使坡面产流提前发生，但对坡面产流量的影响不甚明显；对坡面侵蚀产沙量却有明显的作用。试验条件下，5°坡面有土壤结皮处理的坡面侵蚀产沙量较无土壤结皮处理减少了54%。有土壤结皮处理的10°坡面，在降雨过程中结皮尚未破坏前，其坡面侵蚀产沙量较无土壤结皮处理的对照减少了40%；一旦土壤结皮被破坏，之后的坡面侵蚀产沙量较无土壤结皮处理的对照增加了46%；在整个降雨过程中，10°有土壤结皮处理的坡面侵蚀产沙量较无土壤结皮处理增加了16%。表明土壤结皮对坡面侵蚀的影响与地面坡度有密切关系。

Effects of Soil Crust on Runoff and Sediment on Hillslope in Black Soil Region

Soil surface crust has great impacts on hillslope erosion process. Simulated rainfall experiments were conducted to investigate the effect of soil crust on runoff and sediment yield on hillslope in the black soil region. The experimental design included two kinds of soil surface (crust and non-crust), one rainfall intensity (60 mm/h) and two slope gradients (5° and 10°). Results showed that the runoff occurrence with soil crust treatment was earlier than that of non-crust treatment, but runoff rate was similar for both soil surface treatments. Compared to the non-crust treatment, the sediment yield on 5° slope with crust decreased by 54%; the sediment yield of 10° slope decreased by 40% when the soil crust existed in the process of rainfall because soil crust has the function of restraining sediment generation; but it increased by 46% after the soil crust was broken. The total sediment yield on 10° slope with initial crust increased by 16% compared to that in the non-crust treatment in the duration of the simulated rainfall. Under the experimental conditions, this study results showed that slope gradient was the key factor that soil crust affected soil erosion.