فهرست مطالب a. arabi-yazdi

South Khorasan province، with an average annual rainfall of 180 to 200 mm، Average annual production of over 490 thousand tons of agricultural products، overdraft more than 138 million cubic from groundwater، takes place so of 24 Prairie Independent State، 13 Plains Forbidden، 2 Plains critical prohibited، 3 Plains proposed ban. In this study، the average virtual water crops in South Khorasan Province was about 1312 cubic meters per ton of product and agricultural water use efficiency is 0. 62 kgm3. As a result، rice imported about 7. 76 million cubic meters of water in virtual form due to agricultural product trade in 2008 to 2012. During this period، the largest volume of virtual water export was tomato sauce، potato and apple which declined from 24. 5 to 17. 2 million cubic meters. In 2012، the net water requirement in potential condition for food security of 662،534 populations was about 723 million cubic meters. To achieve food security، requires about 448 thousand tons of food supplies، taking into account the actual conditions and efficiencies of 35%; we need about 2065 million cubic meters of water to form a virtual. The water footprint of province was 1142 million cubic meters or 1723. 7 cubic meters per capita per year.

Demand and supply of water in Iran is unbalanced. This situation has caused a great challenge in water resources management. In order to overcome this problem, the role of international trade of virtual water has been ignored. Virtual water trade is one of the key solutions for water scarcity. Each country should adapt virtual water trade based upon its socio-cultural, economical, and climatic condition of the country. However, before any action is implemented, there is a need to evaluate ecological water footprint (EWF) of the country. EWF is the amount of water which is needed for the population and consumptive use and remediation of all pollution related to this consumption. In this study EWF of Iran has been calculated for the year 2007. The results showed that EWF in Iran is 104 billion cubic meter (bcm) of water in agricultural section. In 2007, Iran has imported 12 bcm of water due to virtual water trade. In this computation, irrigation efficiency has not been included. Considering the amount of 60% for irrigation efficiency virtual water trade in the above mentioned year was 20 bcm. Without this trade, the country had to spend 112 bcm of water for producing all required food in the country which was out of reach.