Optimization of Virtual Water Consumption with Emphasis on Uncertainty of Rainfall and Crop Price: A Case Study: Sari Gherbaran

Abstract
Objective & In the present study, considering the importance of virtual water consumption management and the need to pay attention to the issue of uncertainty in the agricultural sector, a cropping pattern to optimize virtual water consumption with emphasis on the uncertainty of rainfall and crop prices is presented for farmers in Sari Goharbaran.
 
Materials & In order to achieve the objective, a mathematical programming model under uncertain conditions has been used to minimize virtual water consumption and to achieve the certainty equivalent based on the tail value at risk measure. Some of the required data, such as the belief degree of farmers about different levels of price and rainfall, were collected through interviews with the farmers in the study area in 2018. Finally, groupings were made for the belief degree and scale of the farmers' land.
 
The results indicated that the current cropping pattern is not optimal in terms of virtual water consumption and achieving certain profit. Comparison of the results of optimization of cropping pattern in different belief degree groups also showed that the proposed model in more subjective judgment groups and large scale land group, save more on virtual water consumption than more uncertain judgments and small scale land group.
 
According to the results of this study, farmers in the region do not use water optimally in conditions of uncertainty, and the necessary measures should be taken in this regard.