Assessing the Influence of Environmental Factors on Spatial Soil Erosion Risk based on the Certainty Coefficient Method

Abstract

Soil erosion is a very serious ecological problem and remains a highly contentious issue in Nanling National Nature Reserve, China. This paper assessed the spatial relationships between soil erosion risk and the environmental factors affecting soil erosion. Such research is significant for monitoring future land use/cover changes, including agricultural expansion and deterioration of forest resources. First, the soil erosion spatial distribution map was obtained by interpreting consecutive Landsat 8 satellite images, of which the interpreted result was validated via the intensive fieldwork. Then, from the perspective of topography, land cover, soil and rainfall, environmental factors that may influence the soil erosion risk were selected to quantitative test the relationships between soil erosion risk and the environmental factors using a certainty coefficient method. The results indicate that soil erosion is highly correlated to specific slope categories, elevation zones, distance to rivers, land use/cover type, stratum lithology, soil types and annual 24h maximum rainfall. The occurrence probability of soil erosion is high in the area where the slope is larger than 40°. A remarkable variation in soil erosion loss displays in areas above 1300 m of elevation, and areas below 500 m. The probability of soil erosion is the highest in the area within 100 meters of distance to rivers. Cultivated land, grassland and artificial surface land covers have the strongest soil erosion. The probability of soil erosion in the Cambrian and Carboniferous strata is the highest among the lithology categories. The red soil and scrubby-meadow soil have the strongest soil erosion. Soil erosion in the area of annual maximum 24h rainfall between 110 mm and 120 mm is stronger than other area. The reported results provided viable information essential to control soil erosion, reduce soil loss, and achieve sustainable ecological development.

Test of the RUSLE and Key Influencing Factors Using GIS and Probability Methods: A Case Study in Nanling National Nature Reserve, South China

“…e calculated certainty coefficient CF value ranges from − 1 to 1. When the CF value is close to 1, the certainty of soil erosion is great and soil erosion is likely to occur [28]. Conversely, when the CF value is close to -1, the certainty of soil erosion is low and soil erosion is less likely to occur.…”

“…us, the following six categories of 10 variables which closely related to local soil erosion are selected: geology (lithology), topography (LSfactor, elevation, slope type, and aspect), soil (K-factor), climate (R-factor and 10-min maximum wind speed), vegetation (C-factor), and anthropogenic activity (distance to the drainage network). Here, a probability method was developed as follows [28]:…”

“…Sachs and Sarah [27] highlighted that soil erosion was strongly influenced by soil type, slope rate, and vegetation type and coverage. Wang et al [28] quantitatively tested the relationship between overall soil erosion and environment factors in the Nanling National Nature Reserve, China, and found that the soil erosion is mainly distributed in a specific range of environmental factors, such as 500-1300 m elevation, red and scrubby-meadow soil, and >40 slope. However, they did not further discuss the relationship between different types of soil erosion (rill erosion, sheet erosion, gully erosion, and human-induced erosion) and environmental factors.…”

“…Location of the study area: (a) inset map showing the location of Guangdong Province in China, (b) inset map showing the location of the study area in Guangdong Province, and (c) map of the study area with stream order and four major sections.Figure 1is reproduced from Wang et al[28] (under the Creative Commons Attribution License/public domain).…”