Estimation of Soil Erosion in the Chaohu Lake Basin through Modified Soil Erodibility Combined with Gravel Content in the RUSLE Model

Abstract

It is generally acknowledged that soil erosion has become one of the greatest global threats to the human-environment system. Although the Revised Universal Soil Loss Equation (RUSLE) has been widely used for soil erosion estimation, the algorithm for calculating soil erodibility factor (K) in this equation remains limited, particularly in the context of China, which features highly diverse soil types. In order to address the problem, a modified algorithm describing the piecewise function of gravel content and relative soil erosion was used for the first time to modify the soil erodibility factor, because it has been proven that gravel content has an important effect on soil erosion. The Chaohu Lake Basin (CLB) in East China was used as an example to assess whether our proposal can improve the accuracy of soil erodibility calculation and soil erosion estimation compared with measured data. Results show that (1) taking gravel content into account helps to improve the calculation of soil erodibility and soil erosion estimation due to its protection to topsoil; (2) the overall soil erosion in the CLB was low (1.78 Mg·ha −1 ·year −1 ) the majority of which was slight erosion (accounting for 85.6%) and no extremely severe erosion; and (3) inappropriate land use such as steep slope reclamation and excessive vegetation destruction are the main reasons for soil erosion of the CLB. Our study will contribute to decision-makers to develop soil and water conservation policies.

A Comparison Study Between Epic and Modified Epic Models in Assessing the Erodibility for Alluvial Soils

“…But the different values of soil erodility for the two models (as shown in Table 3) is due to the presence of different gravel fraction content in each of studied sites (Vaezi et al, 2017). The lowest values of Kr-model for three sites in comparison to KEPIC-model is related to that the Kr model takes into account in their formula the gravel fraction while the KEPIC has not.Therefore, the values of Kr -model (0.00303 Mg h MJ-1mm -1 ) was found to be low in soil at Albusaif site due to presence of high quantity of gravel fraction in this site in comparison to the other two sites.This result is agree with the Sai et al (2019), who pointed out that is the necessity of introducing the separated gravel as a basic function in calculating the soil erodibility by KEPIC model in alluvial soils or in other soils that have a considerable amount of gravel fraction. This behaviour of the two models can be shown clearly through the secular trend of these models in Figure ( 1) which show that the values Kr -model distribution of the three studied sites are somewhat has lowest trend than of the KEPIC model after the introduction of an equivalent separated gravel.…”

Simulation of Land Use Change and Ecosystem Service Value Dynamics under Ecological Constraints in Anhui Province, China

“…The annual average temperature and annual rainfall data were obtained using spatial interpolation analysis combined with meteorological station data. Soil erosion data were calculated using the improved soil loss estimation model [ 60 ]. Traffic location data were obtained using the distance analysis tool in ArcGIS.…”

Spatiotemporal Dynamics of Ecosystem Service Value Determined by Land-Use Changes in the Urbanization of Anhui Province, China

“…Plains and low hills are the main types of terrain in Anhui province, which is characterized by a high altitude in the south and a low altitude in the north. The annual average rainfall in Anhui province is ∼1300 mm, and rainfall is concentrated in summer and autumn, accounting for 40-60% of the total annual precipitation, which leads to frequent droughts and floods [33]. Anhui province is rich in water resources; the Chaohu Lake is one of the five largest freshwater lakes in China.…”

“…At present, a few ecologically fragile areas in Anhui province have been listed as extremely important regions for ecological protection by the Ministry of Ecology and Environment of the People's Republic of China. Nevertheless, ecological environmental protection has become an important goal of regional development [33]. Therefore, a quantitative assessment of the impact of regional land-use change on the ESV is required for the sustainable development of socio-economic and ecological environment.…”