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Desertification vulnerability in Varamin Plain, Central of Iran
Ammar Rafiei Emam, Farhad Fakhri
Faculty of natural resources, university of Tehran, Karaj P.O.Box 31585-4314, Tehran, Iran.
E-mail: rafiei99@yahoo.com
Ali naghi Rafiei Emam, Amir Ahmadian
Faculty of economic, university of Tehran,Tehran, Iran.
Tel : +98 911 2499262, Fax: +98 21 8966760
Email: ali_rafie@yahoo.com
Introduction
Desertification is a world-wide phenomenon which causes the earth's ecosystems to deteriorate. It affects about two-thirds of the countries of the world, and one-third of the earth's surface, on which one billion people live, namely, one-fifth of the world
Population.
Desertification, as defined is the degradation of the land in arid, semi-arid and sub-humid dry areas caused by climatic changes and human activities. A reduction in the natural potential of the land and depletion in surface and ground water resources accompany it.
The vulnerability of land to desertification is mainly due to Overgrazing and woodcutting, over cultivation practices, and improper water management leading to salinization is the cause of the deterioration of irrigated lands. In addition to vegetation deterioration, erosion, and salinization, desertification effects can be seen in loss of soil fertility, soil compaction, and soil crusting. Urbanization, mining, and recreation are having adverse effects on the land of the same kind as is seen on range, dry farming, and irrigated lands.
As a matter of fact, Desertification is a land degradation problem of major importance in the arid regions of the world. Deterioration in soil and plant cover has adversely affected nearly 50 percent of the land areas as the results of human mismanagement of cultivated and range lands.
Material and Methods
Land degradation involves as complex set of processes of factors, which interact in space and time leading to a decrease in land productivity. Thus, it is necessary to identify the various indicators, which will provide the relevant information to define the desertification prone areas. To this aim, the MEDALUS (Mediterranean Desertification And Land Use: European Commission, 1999) methodology was modified and adopted, and the risk of desertification was evaluated on a regional level by defined the ESA (Environmental Sensitive Area) Index.
ESAs method takes into consideration three broad systems of indicators:
- Ground Water Indicators (Water Table, Cl,
Ec, Sar)
- Land use indicator
- Soil quality indicators (Ec , Sar, Organic Mater ,Texture )
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