Occurrence and erosion susceptibility of German Pelosols and international equivalents

Background: Pelosols are the Soil of the Year 2022 in Germany, Austria and Switzerland. They represent soils with a high clay content (≥45%) in the diagnostic P horizon. Pelosols are nutrient-rich, have a strong capacity for swelling and shrinking, have a challenging water balance with a high portion of nonplant available water and are affected by high traction. Such special characteristics make them challenging soils under agricultural management. Aims: The occurrence, land use management and soil erosion risk of Pelosols in Germany were investigated and compared to their clay-rich soil counterparts on a global scale. Methods: We intersected soil maps of the German and international digital soil mapping with soil erosion data. Results: A high percentage (63%) of Pelosols in Germany are under agricultural use, from which two-thirds are arable farming. Simultaneously, Pelosols have a high risk for soil erosion by water and are the fourth most endangered soil type compared to all soil types in Germany. The average soil erosion loss of Pelosols used for agricultural practices assessed by the Revised Universal Soil Loss Equation (RUSLE) is 2.24 t ha−1 y−1 compared to an average erosion loss of all agriculturally used soils in Germany of 1.65 t ha−1 y−1. From an international perspective, Pelosols in Germany are mostly mapped as haplic Cambisols or haplic Luvisols, as they do not necessarily meet the diagnostic properties of the clay-rich Vertisol soil type. Most Vertisols are classified as Pelosols, but Pelosols do not necessarily fulfil the diagnostic criteria of Vertisols. Vertisols on a global scale have an even higher soil erosion risk than Pelosols in Germany (3.5 t ha−1 y−1). Conclusions: Pelosols and Vertisols, despite their high percentages for agricultural use, have a high soil erosion risk compared to other soil types and thus need special care under agricultural use and adapted protective land use management.