Response of soil erosion and sediment sorting to the transport mechanism on a steep rocky slope

Abstract

A deeper understanding of the sediment characteristics associated with rock fragment content can improve our knowledge of the erosional processes and transport mechanisms of sediments on steep rocky slopes. This research used simulated rainfall experiments lasting for 1 h at a rate of 90 mm h−1 and employed 5 × 1 × 0.4 m parallel troughs filled with purple soils with different rock fragment volumetric contents (0, 5, 10, 20, 30 and 40%) on a 15° slope gradient. For each simulated event, runoff and sediment were sampled at 1‐ and 3‐min intervals, respectively, to study, in detail, the temporal changes in the size distributions of the eroded sediments. The results show that sediment concentrations, soil erosion rates and soil loss ratios significantly decreased as rock fragment content increased for rock fragment contents from 0 to 40% in purple soils. During the transportation process, clay particles often formed aggregates and were then transported as larger particles. Silt particles were more likely to be transported as primary particles with a low degree of sediment aggregation. Sand‐sized particles, which constituted a greater proportion of the original soil than the eroded sediments, were formed from other fine particles and transported as aggregates rather than as primary particles. Suspension‐saltation, which mainly transports fine particles of 0.02–0.05 mm and coarse particles larger than 0.5 mm in size, was the most important transport mechanism on steep rocky slopes. The results of this study can help to explain the inherent laws of erosional processes on steep rocky slopes and can provide a foundation for improving physical models of soil erosion. © 2019 John Wiley & Sons, Ltd.

Determining the Shear Strength and Permeability of Soils for Engineering of New Paddy Field Construction in a Hilly Mountainous Region of Southwestern China

“…Most rainstorms occur between May and October, and the amount of precipitation during this period accounts for~80% of the total annual precipitation. The test soils, classified as regosols in the FAO Taxonomy or entisols in the USDA Taxonomy, are formed from purple rocks or weathering products and are mainly distributed in the sichuan basin of southwestern China [22,23]. ).…”

Spatial and temporal characteristics of soil erosion in a typical karst basin in southwest China and its response to the landscape pattern of rock desertification

“…After introducing D factor by linear correction in RUSLE model, it is found that the average soil erosion modulus of karst area in the basin from 2010 to 2020 is much smaller than that of non-karst area (Wei et al, 2011;Li et al, 2019a), and the accuracy and accuracy of soil erosion estimation in the basin are signi cantly improved (Xie, 2016). The relationship between rock exposure and soil erosion is complex, and there are linear (A Cerdà, 2010), exponential (Martínez-Zavala L, 2008, quadratic function (Han et al, 2019), etc. However, at present, there are few studies on the impact of rocky deserti cation on soil erosion (Ma and Zhang, 2018), and most of them are based on indoor simulation tests and lack of eld positioning observation tests.…”

Characteristics of sediment particle size distribution in the Pisha sandstone area of the middle Yellow River under the effects of vegetation and complex erosion

“…The sediment erosion process is accompanied by the selectivity and transportation of soil particles (Han et al, 2019), which depends on the erosion dynamic characteristics, soil properties and underlying surface conditions (Farenhorst & Bryan, 1995; Harvey, 2001; Kocurek, 1998), among which the erosion dynamic characteristics determine the erosion force of the slope surface, while the soil properties and underlying surface conditions affect the erosion and flushability of the soil; the selectivity and transportation process of eroded sediment under different dynamic characteristics of soils with different properties are completely different (Issa et al, 2010; Wang et al, 2014; Warrington et al, 2009; Zhang et al, 2020). Therefore, the particle size distribution of eroded sediments can not only provide basic information about the erosion process, but also lay the foundation for the construction of soil erosion prediction models (Asadi et al, 2011; Meyer et al, 1992; Shi et al, 2012).…”