Assessment and Measurement of Wind Erosion

Abstract

Wind erosion has become an important soil degradation process on arable land, caused by land use techniques that leave a disturbed, temporarily bare surface or insufficient soil cover material at the surface. Soils that have been formed by aeolian processes over centuries are endangered to be destroyed by the same processes within a very short time. Wind erosion is not only a soil-removing process but also a very effective sorting process. Coarse particles remain in the field, whereas the finest and most valuable parts of the soil are lost, such as particles of the silt and clay fractions and the soil organic matter. This chapter introduces advanced methods to assess wind erosion and to quantify the corresponding soil losses. Evaluation schemes generally consider two categories to determine the extent of wind erosion: the erosivity of the climate and the erodibility of the soil, divided into few classes and linked in simple matrices to derive the wind erosion risk in a comparative way. The German standard DIN 19706 “Soil quality—Determination of the soil exposure risk from wind erosion” was a basis for a Geographic Information System (GIS) risk map of all agricultural fields in Germany. The quantification of wind erosion is based on the measurements of the horizontal fluxes that can be used further to derive soil losses/dust emissions or the deposition of the transported particles. Sufficient depositions can be measured in their thickness and extent to calculate the relocated volume or mass. The comparison of the grain size distribution and the organic carbon content of the original soil, the redistributed material, and the depositions enable the losses of fine particles and organic matter to be calculated. Models of wind erosion have been calibrated to specific conditions of the soil surface and plant cover and refined by wind tunnel experiments. The Fallout-Radionuclide method is suited to identify wind erosion and dust deposition pattern at larger spatial and temporal scales. Finally, remote-sensing and GIS procedures are used to present areas for wind erosion and dust deposition for large landscape units. The methods presented here have been shown to be proven in important agricultural regions around the globe. Conclusions include recommendations for the installation of wind erosion monitoring plots.