A Multi-Objective Programming Model for Irrigation Water and Planting Structure Optimization Based on Pareto Set

A nonlinear multi-objective programming model was established for irrigation water and planting structure allocation considering the characteristics of the interaction and the mutual influence between water and land resources in agricultural systems. With the goal of maximum net irrigation benefit and maximum water efficiency in the irrigation area, the proposed model is established based on the secondary crop water production function in the entire growth period. This model optimizes the allocation of monthly surface water and ground water for each crop as well as the irrigation area planting structure. This study used genetic algorithm to solve the Pareto optimal set of this complex nonlinear multi-objective programming to solve the problem involving loss of result information caused by the traditional solution method. The model was applied to the Yingke irrigation district in the Heihe River Basin;194 groups of non-inferior water and land resources allocation schemes were obtained. Results show that the Pareto optimal set can clearly reflect the game process among targets as well as between land and water resources; moreover, it can fully demonstrate that the process of importance to the crops will change as the target tends to change. The model considers not only the relationship between surface water and groundwater resources but also between water resources and land resources; it also examines the net benefits of irrigation and water use efficiency. These results can provide valuable information that can help in forming decisions pertaining to a wide range of practical applications. © 2019, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.