Cropland water erosion simulated by RUSLE2 with updated erosivity and, temperature and precipitation normals

The Revised Universal Soil Loss Equation 2 (RUSLE2) model has served as the U.S. Department of Agriculture's primary tool for conservation planning. However, one of its key inputs, climate data, has not been updated since that original release, in 2004. The current study is designed to assess and quantify the impact of those updated input climate databases on soil loss estimates for the contiguous United States (CONUS) using RUSLE2. The analyses were based on the two dominant crops, corn/maize ( Zea mays ) and soybean ( Glycine max ), which constitutes a combined 55 % of the total CONUS agricultural area in 1867 counties. The first analysis assessed how well RUSLE2 soil loss using the new climate data mirrored the standard one for the 1970–2000 period. Nationwide comparisons of RUSLE2 outputs showed strong agreement, and the new technique was deemed better based on lower residual errors. The second analysis addressed the question of how soil loss across the US has changed with any changes in climate over time based on nationwide precipitation records to generate five 30-year climate databases: 1970–2000, 1975–2005, 1980–2010, 1985–2015, and 1990–2020. Results suggest a trend of increasing soil loss over time in the central portion of the eastern CONUS. The third study addressed the question of whether the use of generic managements in the previous studies had a significant impact on the results. This was examined by replacing the generic managements with location-specific ones, as allowed by the vast USDA-NRCS management database. Results showed that trends were magnified or reduced by specific combinations of soil type and management schedule and operations, so that future studies should attempt to use spatially-varying combinations. These findings indicate that updates to climate databases could be utilized to improve soil loss estimates and local conservation planning design. • Long-term evaluation of soil loss at continental scale. • Assessing the impact of climate dynamics to soil loss using the RUSLE2 model. • The need for regular updates in climate input databases for soil erosion estimates. • Enhanced soil loss estimates and site-specific conservation plan design.