APPLICATIONS OF THE REVISED UNIVERSAL SOIL LOSS EQUATION (RUSLE) AT NATIONAL AND SUBNATIONAL SCALES: A GLOBAL ASSESSMENT AND A PRACTICAL CASE STUDY IN BRAZIL

Soil is a vital and non-renewable resource fundamental to ecosystem functioning, food security, and landscape stability. Water erosion represents one of the main threats to its conservation. Over the history of Soil Science, several models have been developed to estimate soil loss by erosion, among which the Revised Universal Soil Loss Equation (RUSLE) is one of the most widely applied. The model integrates five factors related to rainfall erosivity, topography, soil properties, land cover, and conservation practices, and advances in remote sensing and Geographic Information Systems (GIS) have enabled its application over large spatial extents. Within this framework, this work combines a systematic review of large-scale RUSLE applications with an empirical spatial assessment of soil erosion in Brazil. The systematic review synthesized studies applying RUSLE at national and subnational scales, resulting in a final dataset of 59 studies. The results indicate a high heterogeneity in soil loss estimates worldwide, ranging from less than 1 Mg ha⁻¹ yr⁻¹ to more than 200 Mg ha⁻¹ yr⁻¹. Rainfall erosivity (R factor) and the length–slope factor (LS) were identified as the main drivers of soil erosion, while land cover (C factor) also plays a relevant role. Additionally, RUSLE was applied to the Northeast and Southeast macroregions of Brazil using open-access data from satellite imagery, meteorological stations, and national sources. Spatial analyses at state and municipal levels show that most areas fall within low erosion classes; however, the Southeast concentrates a higher proportion of areas with elevated soil loss, associated with steeper terrain and urbanized regions, whereas low erosion rates in the Northeast are linked to flatter landscapes, greater vegetation cover, or lower rainfall.