Determination of Soil Wind Erodibility in Eastern Urmia Lake and its Relationship with Soil Physicochemical Properties

In recent years, vast areas of Urmia Lake have dried up and that's why, saline sediments appeared on the surface of the earth, which are very susceptible to erosion. This study was conducted to investigation of wind erosion and its relationship with soil physicochemical properties in eastern land of Urmia Lake. In this research, 96 soil samples were collected from an area of 414000 hectares at a depth of 5 cm based on stratified random sampling method. To measure the wind erodibility, the samples were exposed to 5 different wind velocities (9.5, 11, 12.5, 14.1 and 15 m s-1 at the height of 20 cm) in wind tunnel and finally, its relationship with soil physicochemical properties was investigated. Based on results, soil wind erodibility varied within the range of 76.69-9.98, and with a mean of 10.21 and a coefficient of variation of 94.5% have a relatively high variation in studied area. Wind erosion is significantly affected by soil physical properties, including mean weight diameter, the percent of the size classes 2-4.75, 1.7-2 and 0.1-0.25 mm of soil secondary particles (P<0.001). Based on the results, the erodible fraction (secondary particles smaller than 0.85 mm) had the most appropriate relationship with soil wind erodibility (R2= 0.75, P<0.001) and by increasing it, the soil wind erodibility increased exponentially. Considering the less costly and time-consuming in measuring erodible fraction and also less costly and time-consuming compared with measurement of soil wind erodibility in the field and wind tunnel, this index can be used as a part of soil factor in wind erosion prediction models such as WEQ and RWEQ in the studied area.