扰动土与原状土侵蚀产沙规律研究

Processes of Erosion and Sediment Yield for Disturbed and Undisturbed Soils

采用野外模拟降雨试验,对扰动土与原状土的土壤侵蚀规律进行了研究。结果表明,原状土坡面含沙量呈先下降后波动的过程,扰动土径流含沙量在坡度5°,11°时均呈上升—下降后波动的过程。在坡度相同,雨强相近的情况下,扰动土坡面径流含沙量大于原状土。前期原状土产沙量大于扰动土,后期扰动土产沙量大于原状土。扰动土产沙量大于原状土的时间点随着坡度的增加而提前。产沙速率达到稳定后,扰动土产沙速率大于原状土,差距随着坡度的增大而增大。

Erosion processes of disturbed and undisturbed soils were stualea Dy Results showed that sediment concentration for undisturbed soil decreased first and then fluctuated, while sediment concentration for disturbed soil increased first, then decreased and fluctuated at last. At the same slope gradient and rainfall intensity, sediment concentration for disturbed soil was greater than that for un disturbed soil. In early stage, sediment yield for undisturbed soil was greater than that for disturbed soil, whereas in late stage, sediment yield for disturbed soil was greater. The time when sediment yield for undis turbed soil is greater than that for disturbed soil was advanced with increased slope gradient. After a steady state was reached, eroded sediment rate of disturbed soil was greater than that of undisturbed soil and the gap between disturbed and undisturbed soils became larger with increased slope gradient.