Assessing temporal trends of soil erosion in the Pearl River Basin using the RUSLE model

Healthy soil is the key foundation of the world’s agriculture and an essential resource to ensure the world’s food security. Soil erosion is one of the important forms of soil degradation and a major threat to sustainable terrestrial ecosystem, leading to a series of inevitable consequences such as reduced soil productivity, deteriorated water quality, low food yield, lost reservoir capacity, and even flood hazards. Therefore, controlling soil erosion has been one of the most important tasks of ecosystem management. In our study, we utilized a continuous Landsat satellite image dataset to map soil erosion dynamics (1990-2020) based on RUSLE model across the Pearl River Basin. Based on the results, We also analyzed the spatiotemporal dynamics in soil erosion in the Pearl River Basin from 1990 to 2020, and derived the causes of the changes, to provide a reliable result for soil erosion management and water and soil conservation in the Pearl River Basin. The study results indicated that: (1) The multi-year area-specific soil erosion average in the Pearl River Basin is approximately 538.95 t/(km2·a) with an annual soil loss of approximately 353 million tons; (2) The overall soil erosion displayed a decreasing trend over the  past 30 years with an annual decreasing rate of -13.44(±1.53) t/(km2·a). (3) soil erosion, dominated by low- and moderate-level erosion, primarily happened in the tributary basin of Xijiang River, especially in the areas with slopes > 15°, low vegetation coverage, or poorly managed forests; (4) NDVI and land cover were the dominant factors regulating soil erosion dynamics, versus the insignificant role of precipitation played in the erosion procedure. The study results are valuable for soil erosion management and water conservation in the Pearl River Basin.