Vol18 No.5: 1295-1306
【Title】Characteristics of soil erosion and sediment size distribution for different land uses in the Chinese Mollisol region
【Author】SHEN Hai-ou1;. FENG Jun1; WANG Dong-li2; LI Hong-li1; WANG Yu1*
【Addresses】1 College of Resources and Environment, Jilin Agricultural University, Changchun 130118, China; 2 College of Environmental Science and Engineering, Liaoning Technical University, Fuxin 123000, China
【Corresponding author】WANG Yu
【Citation】Shen HO, Feng J, Wang DL, et al. (2021) Characteristics of soil erosion and sediment size distribution for different land uses in the Chinese Mollisol region. Journal of Mountain Science 18(5). https://doi.org/10.1007/s11629-020-6553-x
【Abstract】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 runoff plots (20 m long and 5 m wide) were subjected to inflow scour experiments (1 L min–1m–2, lasting 40 min). The results showed that the total runoff varied from 2.62 to 6.40 Lm–2and from 8.36 to 20.39 Lm–2on 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–1on the fallow hillslopes and 1.5-3.0 g L–1on 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.
【Keywords】Field plot; Runoff; Sediment size; Simulation; Soil loss