Optimization of Irrigation Scheduling under Different Conditions of Water Supply Using Ant Colony OptimizationAlgorithm

Optimization of agricultural water consumption is very important due to the limitation of water resources and its value in agriculture. Simulation models are a valuable tool for improving management of water consumption in the field because of the quantitative impacts of water on crop performance. In the present study, a model was developed in the MATLAB programming environment 2017 and linked to the ant colony optimization algorithm and the AquaCrop plant growth model. Three different modes of available water volume were considered: A- supplying 100% medium long-term volume of water resources b- supplying 70% medium long-term volume of water resources c- supplying 60% medium long-term volume of water resources. Three different scenarios of depth and irrigation water interval were defined: 1- Depth and similar irrigation interval for autumn and spring crops 2- Depth of different irrigation water and similar interval for autumn and spring crops 3- Depth and different irrigation interval for autumn and spring crops. Scenarios 1, 2 and 3 were implemented for each of the modes A, B and C. For case A, the best schedule of irrigation interval of 8 days and irrigation water depth 25 and 40 mm were obtained for autumn and spring crops, respectively. For case B, irrigation interval of 10 days and irrigation water depths of 24 and 48 mm were obtained for autumn and spring crops. And for case C, the best irrigation schedule was 8 days and depths of 16 and 40 mm for autumn and spring crops were determined. The optimal planting pattern was determined for different scenarios. Maximum area under planting in case of 100% water supply is 23029 hectares and by reducing 40% and 30% water volume, the area under planting will be reduced to 18512 and 17188 hectares, respectively.