High-resolution soil erodibility map of Brazil

Highlights: • High-resolution soil erodibility map of Brazil was calculated. • USLE nomograph algebraic solution and EPIC model were used to calculate K-factor. • K-factor measurements from experimental plots were used in validation process. • USLE nomograph leads to a more precise estimation of K-factor in Brazil. • The highest erodibility values occur in Western Amazon. Large-scale soil erosion modeling has a crucial role in the understanding and planning of soil and water conservation strategies. The lack of spatial data on soil characteristics required to compute the soil erodibility (K-factor) has been one of the greatest obstacles in Brazil. The K-factor is a complex property that expresses the susceptibility of soil to erode according to its inherent characteristics. This factor is a key input parameter for the most widely applied soil erosion models: the Universal Soil Loss Equation (USLE) and the Revised USLE (RUSLE). Here, we computed a high-resolution (250 m cell size) spatially explicit soil erodibility map across Brazil. To compute the K-factor, we applied the equations originally proposed in the USLE nomograph and EPIC, using the following soil properties, organic matter content, soil texture, soil structure, and permeability. To qualitatively evaluate our new K-factor map, its values were compared against standard K-factor values obtained from experimental plots across Brazil. We found that the USLE nomograph leads to a more precise estimation of the K-factor in Brazil than EPIC. The K-factor estimates by the USLE nomograph range from 0.0002 to 0.0636 t ha h ha⁻¹ MJ⁻¹ mm⁻¹, with a mean value of 0.0181 t ha h ha⁻¹ MJ⁻¹ mm⁻¹. Our findings pave the way for a better understanding of soil erosion across multiple scales and thereby contributing to better land-use planning and management in Brazil. The dataset is freely available at doi:https://doi.org/10.5281/zenodo.4279869