Rainfall and inflow effects on soil erosion for hillslopes dominated by sheet erosion or rill erosion in the Chinese Mollisol region
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Erosion agents and patterns profoundly affect hillslope soil loss characteristics. However, few attempts have been made to analyze the effects of rainfall and inflow on soil erosion for hillslopes dominated by sheet erosion or rill erosion in the Chinese Mollisol region. The objective of this study was to discuss the erosive agent (rainfall or inflow), hillslope erosion pattern (sheet erosion or rill erosion) and slope gradient effects on runoff and soil losses. Two soil pans (2.0 m long, 0.5 m wide and 0.5 m deep) with 5° and 10° slopes were subjected to rainfall (0 and 70 mm h–1) and inflow (0 and 70 mm h–1) experiments. Three experimental combinations of rainfall intensity (RI) and inflow rate (IR) were tested using the same water supply of 70 mm by controlling the run time. A flat soil surface and a soil bed with a straight initial rill were prepared manually, and represented hillslopes dominated by sheet erosion and rill erosion, respectively. The results showed that soil losses had greater differences among treatments than total runoff. Soil losses decreased in the order of RI70+IR70 > RI70+IR0 > RI0+IR70. Additionally, soil losses for hillslopes dominated by rill erosion were 1.7–2.2 times greater at 5° and 2.5–6.9 times greater at 10° than those for hillslopes dominated by sheet erosion. The loss of <0.25 mm soil particles and aggregates varying from 47.72%–99.60% of the total soil loss played a dominant role in the sediment. Compared with sheet erosion hillslopes, rill erosion hillslopes selectively transported more microaggregates under a relatively stable rill development stage, but rills transported increasingly more macroaggregates under an active rill development stage. In conclusion, eliminating raindrop impact on relatively gentle hillslopes and preventing rill development on relatively steep hillslopes would be useful measures to decrease soil erosion and soil degradation in the Mollisol region of northeastern China.
KeywordsRunoff Soil loss Slope gradient Rill erosion Mollisol region
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This study was funded by the National Natural Science Foundation of China (Grant Nos. 41601281, 41701313); and the National Key R&D Program of China (Grant No. 2016YFE0202900).
- Ghadiri H, Payne D (1981) Raindrop impact stress. Journal of Soil Science 32: 41–49. https://doi.org/10.1111/j.1365-2389.1981.tb01684.x CrossRefGoogle Scholar
- Liu ZS, Zhang L, Yang ZD, et al. (2014) Derivation of a New Generation of Stormwater Intensity Formula for Changchun. China Water & Wastewater 30(9): 147–150. (In Chinese, with English Abstract)Google Scholar
- Ou Y, Rousseau AN, Wang LX, Yan BX (2017) Spatio–temporal patterns of soil organic carbon and pH in relation to environmental factors–A case study of the Black Soil Region of Northeastern China. Agriculture, Ecosystems and Environment 245: 22–31. https://doi.org/10.1016/j.agee.2017.05.003 CrossRefGoogle Scholar
- Tayfur G, Kavvas ML (1994) Spatially averaged conservation equations for interacting rill–interrill area overland flows. Journal of Hydraulic Engineering 120: 1426–1448. https://doi.org/10.1061/(ASCE)0733-9429(1994)120:12(1426) CrossRefGoogle Scholar
- Yang QS, Zheng FL, Wen LL, et al. (2011) Effects of mulch cover on hillslope soil erosion and nutrient loss in black soil region of northeast China. Bulletin of Soil and Water Conservation 31(2): 1–5. (in Chinese, with English Abstract) https://doi.org/10.13961/j.cnki.stbctb.2011.02.028 Google Scholar