decision support system for economic value of irrigation water with reducing the food gap in agro-ecological zones

introduction: water scarcity has become a global issue due to its direct relationship with food security. for this reason, the need for the long-term sustainable use of water necessitates the application of effective strategies. in this regard, strategic programs are utilized in water resource management and agricultural policies in order to increase self-sufficiency, to reduce the food gap, to decrease the cultivation of water based products, to maximize the economic value of water and to guarantee efficient allocation of resources among different activities in most parts of the world. the main objective of this study is to develop a decision support system to achieve the above-mentioned policies and strategies in the ten agricultural and ecological zones in the country according to the amount of virtual water for crop production. data and methods: the decision support system seeks to introduce an optimum pattern and to investigate the current status of water resources and determine the food gap and virtual economic value by means of a linear programming model. it intends also to determine the return on investment of crop production in each region. our goal of this research is to maximize the value of virtual water with respect to land and availability of surface water and groundwater constraints. we also consider socio-economic constraints to ensure minimum and maximum area under cultivation in every region. in order to achieve accurate results, the social value of goods and inputs has been used in the model. in determining the social value of all goods and tradable inputs, prices of the border with a shadow exchange rate are used. given the importance of addressing the amount of water used to produce goods, the virtual water content of products on maximizing the economic value of water is used in this study. due to climatic conditions and consequently the performance of production in different regions, we use water requirement to crop yield ratio for every region for calculation of the virtual water content of a product. in this study, water valuation was based on value added inputs, while social values were used as criteria in its calculation. the data are gathered from the database of the ministry of agriculture, ministry of energy and the relevant agencies in the region. we used the 32.5 edition of gams software to estimate the proposed model. results: the results show the amount of water used by farmers to grow major crops in different regions in 1392, was 19 billion cubic meters. central zagros with 3.8 billion cubic meters and the central dry zone with 1.2 billion cubic meters have respectively the largest and smallest water consumption. the results also showed the greatest change and lowest change in economic value of irrigation water related to wet wheat and wet cotton respectively. the regional view, the greatest and the lowest value of water refers respectively to the south zagros region and the region of khuzestan. research results show that the pattern of demand reduces the food gap through increased cultivation of some strategic products. in order to reduce the food gap, one of the most important strategies is the increased cultivation of the wheat crop. conclusion: this study provided a cultivating pattern in order to meet two important goals: cutting water consumption and reducing the food gap by increasing the cultivation of strategic crops such as wheat. in fact, by implementing appropriate logistic policies, the government and politicians can achieve the aforementioned objectives by diversifying the current cultivation pattern in the desired region in compliance with environmental, economic and food security and health security considerations. the economic value of irrigation water and reduction of the area under cultivation is also a consequence of the proposed program. instead of providing constant value in all regions of a country, providing an optimal cultivation pattern while considering the exact value of virtual water is a better policy. the proposed cropping pattern reduces food gap and the area of water-based production cultivation and reduces water consumption, which can be used for producing strategic crops. the proposed cropping pattern increases the economic value of water by 20%. indeed, it suggests that acreage crops such as wheat, pulses, and oil seeds are increased and rice and sugar beet cultivation is decreased. the main objective of the proposed cropping patterns to reduce the food gap and increase the welfare of consumers.