Abstract
Rainfall events coupled with shallow and gravelly sloping farmland have led to serious soil erosion and associated problems in the Three Gorges reservoir. Previous studies have shown that the use of vegetation is an effective way to control soil erosion. Therefore, an artificial, simulated rainfall experiment study is conducted to determine the effect of rainfall intensity and vegetation cover on runoff volume, sediment load, and runoff hydraulics characteristics. The experiment consists of seven vegetation treatments subjected to three rainfall intensities on a soil that contains rock fragments on a slope of 30°. The results indicate that the runoff volume and sediment load of the bare plot were greater than those of vegetation-covered plots under three different rainfall intensities. When Cynodon dactylon and Indigofera amblyantha were applied together, the plot displayed the best performance for soil loss control, with a reduction of 87.88%–99.11%. According to a redundancy analysis, the change in rainfall intensity had the least impact on the Reynolds number and the runoff volume of the herb-shrub mixed plot in this study. These findings suggest that the effect of combining Cynodon dactylon and Indigofera amblyantha and increasing the vegetation coverage is an effective solution for soil and water loss conservation. The application of this method can alleviate environmental stress on the Three Gorges reservoir.
Highlights
Soil erosion is a major environmental problem worldwide, especially the water erosion caused by rainfall [1]
Studies regarding runoff and sediment yield effects, hydraulic characteristics, and the relationship between them are conducive to quantitative research on the mechanism of slope soil erosion under various vegetation covers. erefore, in this study, soil containing rock fragments slope is used as the subject of study, and research on the effect of seven levels of vegetation coverage and three levels of rainfall intensities on the erosion characteristics of soil slopes that contain rock fragments are examined. e objective of this study is to evaluate the impact on soil and water loss resulting from different rainfall intensities and vegetation treatments and apply this information to improve vegetation restoration models that aim to protect water and soil loss
Under the same rainfall intensity and vegetation type, the runoff volume decreased with increasing vegetation coverage. e variation in the runoff volume with increasing duration of rainfall showed an unsteady increase in runoff volume followed by a steady condition. en, the runoff volume remained nearly constant with small variations until the end of each rainfall event, though the steady points of each plot were different and occurred at different times. e process of sediment loading exhibited greater fluctuations compared with runoff volume, especially in the CK plot. e sediment loads mostly increased with prolonged rainfall duration as a whole, and the sediment loads exhibited different degrees of dependence on vegetation coverage and rainfall intensity
Summary
Soil erosion is a major environmental problem worldwide, especially the water erosion caused by rainfall [1]. E ree Gorges reservoir is located in the lower section of the upper reaches of the Yangtze river, and the total area of this region is approximately 58000 km. E area of soil erosion in the ree Gorges reservoir constitutes 51% of the total region, and the annual average amount of soil erosion is nearly 200 million tons, which is one of the four most serious soil and water erosion regions of the upper Yangtze river [5, 6]. Soil erosion of farmland has accounted for 60% of the total soil erosion in the ree Gorges reservoir region. Rainfall is the main driver of soil loss in sloped farmlands, while the ree Gorges reservoir has an abundance of precipitation and rainstorms. Artificial restoration measures have been used to prohibit the land from farming [9]. us, research that investigates erosion characteristics on sloped farmland is of very practical significance
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