The effect of 120-day winds on the safety of Sistan region

Sistan and Balouchestan climate is located in the dry and wild land (Khosravi، 2004:163-187). This climate moves the moist particles in the atmosphere because it is dry، since no other humid weather is being replaced، the relative humidity increases and causes the weather to be dried. In such circumstances increase in vaporization of the weather which cause the soil to have more moisture and prone to wind erosion. Wind erosion destroys the nutritive particles of the soil which are less than 2  such as humus، clay and the soil salts. The wind erosion may move these particles to the remote areas in form of dust storms) Ranjbar et al. 2005:79. The recent studies show that 14 provinces of the country are affected by erosion winds; Sistan and Balouchestan province which is 229174 Hectare becomes the first in this category (Iran Manesh، 2007:26). In Sistan، desert is located in this region besides the important and populated cities such as Zabul، Zehak، Dust Mohammad، Hirmand and Adimi (census of Sistan and Balouchestan province 2006:42). This region is 15195 km2 and its cultivate lands are 140 Hectare which Hirmand river passes among them، they included 67. 2% of farms (Akbari Moghaddam and Ee’tesam، 1991:18). The morphologic and climatic features show the dominance of wild lands over this region One of the important factors that influence the creation of dust in the region، is the drought phenomenon. It has affected the regional development. Drought is one of the main factors of erosion. Inevitably the main factor of erosion in this region is dust and sand storms due to the 120 day winds of Sistan. Wind erosion reduces soil fertility، on the other hand destroys and bury the farm lands، buildings، industrial and infrastructure institutions out of lands (Negaresh: 2009:83-73)، Which ultimately will have a significant impact on regional security in Sistan.