Increasing water scarcity has posed a major constraint to sustain foodproduction in many parts of the world. To study the situation at theregional level, we took Iran as an example and analyzed how an intra-country"virtual water trade strategy" (VWTS) may help improve cereal productionas well as alleviate the water scarcity problem. This strategy calls, inpart, for the adjustment of the structure of cropping pattern (ASCP) andinterregional food trade where crop yield and crop water productivity aswell as local economic and social conditions are taken into account. Weconstructed a systematic framework to assess ASCP at the provincial levelunder various driving forces and constraints. A mixed-integer,multi-objective, linear optimization model was developed and solved bylinear programming. Data from 1990–2004 were used to account for yearlyfluctuations of water availability and food production. Five scenarios weredesigned aimed at maximizing the national cereal production while meetingcertain levels of wheat self-sufficiency under various water and landconstraints in individual provinces. The results show that under thebaseline scenario, which assumes a continuation of the existing water useand food policy at the national level, some ASCP scenarios could producemore wheat with less water. Based on different scenarios in ASCP, wecalculated that 31% to 100% of the total wheat shortage in the deficitprovinces could be supplied by the wheat surplus provinces. As a result,wheat deficit provinces would receive 3.5 billion m3 to 5.5 billion m3 of virtual water by importing wheat from surplus provinces.
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