Optimal land allocation and irrigation scheduling to maximize the economic utility

Attaining sustainable agriculture requires water consumption management. A water allocation optimization model was developed for the Moghan irrigation network (northwest of Iran) based on the AquaCrop plug-in model. The genetic algorithm was applied to optimize water allocation for five main crops, including wheat, first-cultivation maize, second-cultivation maize, soybeans, and alfalfa. The heuristic economic utility (EU) function was used as the objective function to optimize water allocation. In this function, drained water salinity was applied as a penalty factor to the total benefit, and soil salinity deterioration due to irrigation was also considered as a factor in each crop’s benefit. The results showed that the optimal allocated water depth was 17% less than the normal water consumption. Moreover, the application of soil water salinity coefficients did not affect the ratio of EU to EB (economic benefits) for wheat and alfalfa. However, first-cultivation maize, second-cultivation maize, and soybeans cultivation led to a reduction in EU within the study area. A combination of the crops cultivation led to a change in river water quality and an 8.2% reduction in the ratio of EU to EB function.