پهنه‌بندی شهرستان‌های استان کرمانشاه بر اساس مقدار و ارزش آب مجازی محصولات عمده زراعی

Introduction: Kermanshah Province with one million hectares of arable land play an important role in food security and economy of Kermanshah province. For example, Kermanshah province holds third in wheat yield per hectare; second in chickpea production; third in maize production; third in sugar beet yield per hectare; and seventh in tomato production. However, unsustainable behavior of farmers in one hand and overuse of water consumption have depleted water reserves which in turn has developed “prohibited plains” in the region. For example, several regions such as Mahidasht, Islamabad, and Kangavar are consider as forbidden areas and still extending in size. In addition, with the continued overuse of water resources we will soon experience huge sinkholes across the province. Therefore, there is a need to study the content and value of virtual water in order to zone cultivated areas based on virtual water. This could be an effective way to maintain water resources and prevent environmental crises.
Materials and Methods: This study used quantitative documentary research method. Using secondary data source, we collected data from various sources such as FAO data bank, Agricultural Jihad Organization data source, Meteorological organization, Agricultural Research Center, and Department of Soil and Water Management. This documentary research sought to investigate the content and value of virtual water used in irrigated and rainfed farming across wheat, barley, chickpea, maize, sugar beet, and tomatoes during 2014-2015 using CROPWAT, AGWAT, and EXCEL software. In addition, the share of green and blue virtual water was estimated in the study. Finally, 12 provinces were zoned from classes A to Z based on virtual water content and value of the products. 
Results and Discussion: Results revealed that wheat with 1.96 to 3.68 m3/kg is the most consumable product that about 60 percent of the cultivated areas of wheat are located in areas of the province that are inappropriate in terms of content and value of virtual water. Also, tomato with the value of 0.09 to 0.38 m3/kg had the lowest virtual water content and average value of virtual water. According to the results, the sugar beet product is in desirable condition in terms of virtual water content and had moderate conditions in virtual water value.  Finally, about 80% of maize produced in areas that are not in a desirable position in terms of virtual water content and value.
Results of green and blue virtual water showed that spring products such as sugar beet, tomatoes and maize received their water requirement from surface and groundwater resources. In addition, the largest blue component of wheat was related to Harsin city and the lowest was related to Javanrod city. For irrigated barley, the smallest and the largest share of blue virtual water were related to cities of Qasr Shirin and Sahne respectively.
Conclusion: Overall, the results of this study revealed that irrigated wheat and barley have a poor condition in terms of the content and the value of virtual water. However, since wheat and barley are considered as a strategic products policymaker should take appropriate measures in order to provide sustainable cultivation of wheat and barley. For example, improved farming, plant breeding, changing the growing season according to climatic conditions, developing cultivation in suitable areas, as well as applying appropriate pricing and support policies, including training of beneficiaries, and improving insurance policies could provide appropriate measures if Iran is to be self-sufficient in wheat and barley production.
Results of this study has practical significance for agricultural policymakers in Iran in general and Kermanshah province in particular.  For example, zoning of crop cultivation based on the content and value of virtual water provided in this study can be an effective tool in modelling cropping pattern and sound water management policies. In addition, effective cropping pattern as well as sound water management resources would encourage farmers to engage in climate smart agriculture. Moreover, cultivation zoning based on content and value of virtual water is considered as a climate smart agriculture technique. This in turn would create resilient farming system in the study area. Through resilient farming system, farmers better adapt to climatic condition more effectively.