Methods for quantifying wind erosion in steppe regions

Abstract

Wind erosion has become an important soil degradation process in the steppe regions around the world caused predominantly by overgrazing and by transforming steppe into arable land. Soils, formed by aeolian processes over centuries, are now at risk of being destroyed by the same processes within a short space of time. The main problem with wind erosion is how it is perceived. Although heavy sand and dust storms occasionally attract attention, erosive processes usually go unnoticed. Annual average soil losses up to 40 t ha-1 are possible without any visible sign of erosion or deposition. The following chapter introduces common methods for assessing wind erosion and for quantifying the soil losses involved. Consideration of the special characteristics of steppe regions is discussed to enable methods to be applied successfully. Quantification of wind erosion is based on measurements of horizontal fluxes, which can additionally be used to derive soil losses/dust emissions or the deposition of transported particles. The thickness and extent of depositions can be measured to calculate the relocated volume or mass. Losses of fine particles and organic matter can be derived by comparing the grain size distribution and organic matter content of the original soil and depositions. The fallout radionuclide method (FRN, especially137Cs) is suitable for identifying wind erosion and dust deposition patterns at larger spatial and temporal scales. Remote sensing and GIS procedures are finally used to present wind erosion and dust deposition areas for large landscape units.