Soil-PM loss by wind erosion from agricultural Loess fields in the east Mediterranean

Many soils are subjected to wind erosion and dust emission processes. This may result in a loss of essential system-resources and soil degradation. Agricultural activities change the intrinsic soil properties and the soil aggregation, and thus the soil erodibility to wind and water forces. The research focuses on the aeolian (by wind) loss of Particulate Matter (PM) that is less than 10 μm in diameter – the size fraction of clay, organic matter and nutrients in the soil. Various agriculture Loess soils in a semi-arid climate zone were analyzed for physical, chemical and biological properties. A boundary-layer wind tunnel has been used to study soil erosion and dust emission by simulation and quantification of high-resolution wind processes. Wind erosion experiments were conducted in agriculture fields of rain-fed conventional practices and organic practices alternating with grazing. Clay content, organic matter, and bacterial diversity were shown to be influenced by the practice type. The erosion experiments revealed changes in dust emission and PM fluxes in response to the topsoil properties and the wind velocity.  The dus process indicates loss of soil-PM and specific nutrients. Annual balance of soil-PM was calculated by analyzing the output by dust emission and the input by atmospheric dust deposition as the major source of PM. The results highlight a negative balance of PM in all the soils that are subjected to human-induced topsoil disturbance and decrease in soil aggregation. The results can reduce uncertainties in models of dust emission from agricultural fields, and may provide essential information for developing management strategies of soil conservation.