Change pathway and intersection of rainfall, soil, and land use influencing water-related soil erosion
Erqi Xu, Hongqi Zhang
Abstract
Soil erosion causes fertility loss and land degradation, threatening food security and environmental quality. Understanding the spatial relationship and joint impact of factors on the water-related soil erosion can help combat erosion. Change pathway and intersection of trigger factors, key metrics for determining the soil erosion aggravation or improvement, remain unclear and limited in the quantification in previous researches. To solve this problem, this study performed a spatially statistical exploration by using multiple models. Taking the Yili region as the case-study area, the field soil survey, remote sensing inversion and modified Revised Universal Soil Loss Equation were used to estimate the soil erosion in 1990 and 2015. Then, a spatial analysis model was used to quantify the relative importance of multiple indicators and mutual interactions in the soil erosion. The spatial distribution of soil erosion was shown to be basically related to topography with the largest importance in Yili region. Importance of land use, rainfall, and soil changes along with the rugged topography influencing the soil erosion evolution decreased successively. The largest interacted impact was found in the topography with a non-linear enhancement with vegetation factor. The decrease in soil erosion cannot be explained by the increase in rainfall erosivity, but it is likely to the result of land-use changes, reflected in the improvement of the vegetation cover and management factor and erosion control practice factor within the sloping areas. Examining the spatial consistency and intersection of triggering factors, it implied that reasonably reclaiming the desert grassland with the soil improvement and biomass accumulation would mitigate the soil erosion in the Yili region. Our study demonstrated that quantifying the importance for the different pathways of changing factors and their intersection would provide a better understanding and new insight into the soil erosion process.