Determination and evaluation of agricultural water productivity of some major crops in different regions of Iran (Regions: Kerman, Hamedan, Moghan, Golestan, Khuzestan) sector.

Agriculture plays an important role in the economy of Iran. It accounts for 18% of the Gross Domestic Product (GDP), 25% of employment, supply of more than 85% of food requirements, 25% of non-oil exports, and 90% of raw materials used in the Industries. The country is situated in one of the most arid regions of the world. The average annual precipitation is 250 mm (less than one-third of the world average precipitation). Moreover to aridity, distribution of rainfall in Iran is very irregular and non-equitable and the country faces with drought hazards periodically. Despite large reliance of the country on agriculture, especially irrigated agriculture, water resources required for the agricultural production is very limited. Therefore, availability of fresh water resources is the most limiting factor and vital Currently more than 93% of water consumption (84 BCM) is used for irrigation of 8.1 million hectare irrigated agriculture. As agriculture in general and irrigated agriculture in specific is the greatest consumer of water in the countryandrsquos economical sectors, obviously the major losses of water occur in Yet we know that, with the growing demand for water for industry and municipalities, combined with environmental concerns, there will be less water for agriculture in the country in future, therefore agricultural water productivity have to be increased. Based on the latest agricultural static, the country produced 67 million tons agricultural products from 84 BCM of water consumed. Therefore, currently the countryandrsquos average WP is almost 0.8 Kg/ m3 which seems quite low in comparison to the worldandrsquos value. However, in order to have reliable data on specific WP of some major crops in different regions of the country and under different farmer management and for the purpose of planning of agricultural production from limited water resources, some field studies were conducted in five regions in the country namely Kerman, Hamedan, Moghan, Golestan, and Khuzestan. In field trials, the gross volume of water applied to field by the farmer and total crop production was measured in each irrigation event and following harvesting respectively. Then the crop WP in Kg/m3 was determined for Based on results, the WP for the Wheat, Sugarbeet (sugar), Sugarcane, Potato, Silage Corn, Cotton, Alfalfa, Barley, and Chickpea was 0.11-1.87, 0.22-1.70, 0.25-0.44, 1.00-5.70, 4.34-9.11, 0.48-0.92, 1.34-1.63, 0.56, and 0.18 Kg/m3 respectively. Iranandrsquos population is estimated to reach 89 million by year 2020. However, the total agricultural production is expected to be 172 million tons, including 160 million tons from irrigated agriculture, while the total water supply for agriculture will be about 100 BCM. Possibility of increasing in water resources in country is very limited (21% after 20 years) while agricultural production from irrigated farming has to be increased significantly in year 2020. This implies that present water use efficiencies (0.8 Kg/m3 in overall) have to be at least doubled by year 2020. However, increase in WP may produce more food from agricultural crops but may not guarantee water saving and a reduction on intensive pressure on fresh water resources consumption in the country.