RUSLE predicts soil loss due to water erosion as a function of climate erosivity (influenced by amount and intensity of rainfall), topography, soil erodibility, and vegetation cover/management (Renard et al., 1997).
Studies on the variation of water erosion with reference to rainfall, soil properties, topography, land use and vegetation cover will help further the understanding of erosion phenomena. Soil and topography have a strong influence on water erosion, but they are relatively stable.
Therefore, scientists attribute increased soil erosion mainly to rainstorms, inappropriate land use and degraded vegetation (Alatorre et al., 2012; Mohammad and Adam, 2010).
However, due to their interactions, the relationships among precipitation, vegetation and erosion are uncertain and complex (Xu, 2005). Vegetation mitigates soil erosion by its canopy, roots, and litter components, and the effect on soil erosion is influenced by the composition, structure, and growth pattern of the plant community providing the cover (Bakker et al., 2005; Gyssels et al., 2005).
Thus, a positive or negative correlation between precipitation and erosivity mainly depends on the land use and vegetation cover conditions. Soil erosion in the hilly and gully regions on the Loess Plateau showed an evident erosion-resistance due to increase in the vegetation cover (Sun et al., 2013).
Plant cover and land uses are considered the most important influences and, to some extent, exceed the influence of rainfall intensity and slope gradient (Kosmas et al., 1997;
Thornes, 1990). Often, a loss of vegetation cover leads to increasing runoff and erosion (Al-Seikh, 2006; Singer and Le Bissonnais, 1998).