Determining the optimal cropping patterns of farmlands using irrigation planning model (IPM)

Due to limitation of available water and soil resources in Iran, the challenge of optimizing the utilization of these resources has become more significant. In this study it was attempted to maximize the project benefit, estimating crop water requirements at different growth stages, and optimizing the cropping pattern and irrigation management. In order to achieve these objectives mathematical model was solved with simple genetic algorithm (GA) and linear programming (LP) methods. The proposed model was applied to an irrigation project with 7000 ha of farmland irrigated by the main canal network of Doroodzan dam (Fars province). Comparing the optimal cropping pattern proposed by this model (IPM) with those practiced by the farmers showed that the model had a good consistency with farmers’ decisions for cultivating different crops. The results of this model also indicated that optimal planting pattern (in the 1st and 2nd growing season) was the same for GA and LP models. To find the best response from GA in this study the number of generations of 800, population size of 100, probability of crossover of 0.6, and probability of mutation of 0.02 was considered.