Characteristics of soil erosion and sediment size distribution for different land uses in the Chinese Mollisol region

• 作者: SHEN Hai-ou FENG Jun WANG Dong-li LI Hong-li WANG Yu
• 来源期刊: 山地科学学报（英文版）
• 年，卷（期）: 2021,（5）
• 页码范围: 1295-1306
• 页数: 12页
• 语种: 英文

摘要

Soil erosion is currently a major contributor to the degradation of global soil resources.The characteristics of sediment size distribution affect soil erosion processes.However,few studies have quantitatively explored soil erosion processes and sediment size distributions on natural hillslopes for different land uses,especially in the Chinese Mollisol region.The objective of this study was to investigate the impacts of land uses (corn,fallow,buffer strip and bare hillslopes) under 5° and 10° slope gradients on total runoff,runoff rates,soil losses,sediment concentration processes,and sediment size distributions.Natural runoffplots (20 m long and 5 m wide) were subjected to inflow scour experiments (1 L min-1 m-2,lasting 40 min).The results showed that the total runoff varied from 2.62 to 6.40 L m-2 and from 8.36 to 20.39 L m-2 on hillslopes at 5° and 10°,respectively.The changes in runoff rates versus run time exhibited gradual increasing trends at 5°,but exhibited initial rapidly increasing trends and then relatively stable trends at 10°.Fallow hillslopes produced the lowest soil losses,which were 45.34％-45.92％,2.74％-6.72％ and 1.68％-3.44％ for the corn,buffer strip and bare hillslopes,respectively.Most sediment concentrations were very small and stabilized between 0.5-2.0 g L-1 on the fallow hillslopes and 1.5-3.0 g L-1 on the corn hillslopes at 5°,but the changing trends in sediment concentration versus run time for the four land uses generally decreased at 10°.Furthermore,it was demonstrated that the proportion of sediment ＜0.25 mm was the largest in comparison with the other sediment size fractions,and ＜0.25 mm soil particles and aggregates played a dominant role in soil aggregate loss under different land uses.Thus,protecting these precious soil particles and aggregates by applying proper soil conservation measures especially for the relatively gentle hillslopes was particularly important.Additionally,the fallow hillslope with greater soil and water conservation capacities was very suitable for the Mollisol hillslopes.