Investigating the relationship of dust concentration with surface moisture and particle size distribution of soil using a portable wind erosion simulator: A case study of the west regions of Khuzestan province

The potential of soils for wind erosion is related to such agents as the particle size distribution of the surface texture, surface moisture, and wind velocity. The relationship of dust concentration with surface moisture and particle size distribution of soil is investigated in this research using a portable wind erosion simulator. The measurements were done in 10 moisture-apt and 11 wind-erosion-apt regions. Field studies have shown an increase in the threshold friction velocity and a decrease in the produced dust concentration as well as an increase in the moisture of surface soil (0-3 cm) from zero to 3%. Also, the dust concentration falls to almost zero at the moisture of 2.8%. The soil of region 6 had the minimum and the soil of region 2 had the most increase in the threshold velocity. Also, the soil of region 3 in dry conditions had the most dust produced for 161.26 mg m^-3  and the soil of region 2 in the same conditions had the lowest dust emission for 101.23 mg m^-3. So, the variation in the decrease rate of dust concentration is different for different soil regions, but dust concentration drastically decreases toward zero in all the regions at the moisture of 2.2%. Threshold friction velocity as well as surface moisture increases when the surface soil contains more particles with sizes of less than 100 microns. Also, soil potential for erosion increases in dry conditions when more particles with sizes of less than 75 microns are available in the soil surface texture.