An assessment of erosivity distribution and its influence on the effectiveness of land use conversion for reducing soil erosion in Jiangxi, China

Rainfall and land use conversion are important factors influencing soil erosion. Differing from the stationary land use type, land use conversion is a process of dynamic change usually spanning several decades. Soil erosion modeling using historic land use data offers an opportunity to study the impacts of actual land use conversion on soil erosion. However, rainfall has been taken into account only in a few studies because its spatio-temporal distribution often varies greatly over a long period of time. In this article, the erosivity index was used to quantify the erosive force of rainfall. Based on entropy theory, erosivity distribution of study area during the 1988 to 2013 period was analyzed. Two extreme zones, Zone I and Zone II, with highest and lowest annual erosivity, respectively, were identified. The intensity of soil erosion among land use types are: farmland > orchard > grass/open forest > shrub > forest. Zone I has severer soil erosion than Zone II. The effectiveness of land use conversion for reducing soil erosion varies between different erosivity zones. Farmland–forest conversion is considered as the first choice to reduce soil erosion when land use conversion is implemented. The conversions of farmland–grassland and farmland–open forest can be used as important supplements to conversion of farmland–forest in low erosivity zone of the study area, although they do not perform well under higher erosivity situation.