The presence of surface crust is an obvious phenomenon seems indicative of soil
degradation ( Stoops, 1984 ). The desert crusts in Iran are mainly situated in the salt
lakes of the playas. Goudharzi ( 1970 ) showed that playa are the site of chloride,
sulfate, nitrate and borate. Some studies showed the predominance of salt crust and salt
flat zone in the Iranian playas. All the Iranian playas with different surface
characteristics exist in areas where the annual evaporation is considerably greater than
annual precipitation. With evaporation of water from the flooded playa, salt
concentration increases until crystals of salts begin to be precipitated at its saturation
point. The following types of crusts have been recognized in the Iranian deserts: