Climate and land use changes explain variation in the A horizon and soil thickness in the United States

Understanding spatio-temporal changes in soil thickness and their natural and anthropogenic driving factors are essential for earth system modeling and natural resource conservation. This study compiled long-term (1950–2018), large-scale (conterminous United States) topsoil (A horizon) and solum thickness data to quantify their spatial and temporal variations. Climate was found associated with the spatial distribution of soil thickness, and land use and erosion associated with its temporal variation. Severe A horizon loss primarily occurred in Mollisols of the Central Great Plains, Alfisols on steep slopes, and soils under cropping. These findings enhanced our understanding of soil formation and biogeochemical cycles during the Anthropocene and identified regions for conservation practices.

Yakun Zhang, Alfred E. Hartemink, Tom Vanwalleghem, Benito Roberto Bonfatti, Steven Moen