The Effect of Physical Crust Development and Disturbance on Erodibility and Dust Emission in Laboratory Conditions

Soil surface crusting, especially the physical type, is an important feature of dust source areas in Khuzestan province, which can have a significant impact on soil protection against wind erosion. But in most wind erosion studies, it has not been considered. The aim of this study was to investigate the effect of physical crust disturbance caused by livestock traffic on soil crusted erodibility and dust emission. For this purpose, three dominant soils with the characteristic of surface crust formation were selected from the areas and transferred to the laboratory. The soils were placed into wind tunnel trays and subjected to a simulated rainfall to form a physical crust on their surfaces. After the soils dried and the physical crust formed, the trays were exposed to different trampling by livestock's hoof including 1, 2 and 5 crossings. The trays were then transferred to a wind tunnel laboratory and threshold friction velocity (TFV), erosion rate and PM10 emission flux were measured. The results showed that erosion and dust diffusion in the control treatment (without livestock traffic) was zero in all three soil types and with increasing the number of livestock traffic from one to five times TFV decreased by 25 to 49%, and the amount soil erosion and dust emission increased between 54-317% and 80-545%, respectively. The physical crust of sandy soil was more sensitive to livestock traffic than clay loam and silt loam. The findings of this study show that the formation of physical crust in this area is a desirable and valuable feature for inhibiting erosion and dust, which acts as a natural stabilizer and protecting them can have a huge impact on dust control.