The study on the effects of desert pavement on wind erodibility (Case study: Yazd- Ardakan plain)

Destruction and manipulation in the desert pavement due to changes in land use is one of the serious problems in arid and hyper-arid regions throughout the world. Desert pavement is one of the important geomorphologic properties, providing natural safety mulch in central plain of Iran. In other words, desert pavement in arid regions plays the role of vegetation in humid area. In recent paper, desert pavement coverage was measured by random sampling in 20×20 (cm×cm) plots in the faces of coarse, medium and fine glacial plains of Yazd-Ardakan. Soil Wind Erodibility (SWE) and Wind Threshold Velocity (WTV) were determined in wind erosion-meter tunnel and in two natural and disturbed conditions. Results showed that the percentage of desert pavement coverage varied in the range of 83.3±5.1 in coarse glacial. SWE and WTV varied at about 19±3.1kg/ha.hr and 9.4±0.4 m/s at a height of 2m, respectively. In medium glacial plain, desert pavement coverage varied in the range of 70±14%. SWE and WTV were determined at about 34±19.9 kg/ha.hr and WTV varied in the range of 8.5±0.8 m/s. Fine glacial plain was bare and without desert pavement coverage. SWE and WTV varied at about 1300.9±1087 kg/ha.hr and 5.2±0.5 m/s, respectively. According to the results, soil erosion resulted in increased potential for wind erodibility at about 25 times greater than natural conditions. Also, with removing desert pavement, WTV decreased by about half. Our results indicate the necessity of attention to the desert pavement as a natural safety factor so that human manipulation and intervention in fragile and sensitive conditions of arid regions will not result in severe and irreversible damage.