干旱区生态环境知识资源中心

Planting structure influences the economic, social, and ecological benefits of crop farming as well as the use efficiency of water and arable land resources, and so crop planning (CP) benefits for agricultural sustainable development and soil resources utilization. The projection pursuit evaluation (PPE) model is put forward to solve the problem of selecting an optimizing scheme for CP by considering the indices of water-saving and economic, social, and ecological benefits. The real-coding-based accelerating genetic algorithm (RAGA) is introduced to accelerate the calculation process. The model can translate multi-indices into a single index by transforming high-dimensional data to low-dimensional space, which helps evaluate CP optimizing schemes. For example, the model is used to evaluate and select an optimal scheme of CP in the middle reaches of the Heihe mainstream basin in the arid area of northwest China. According to four criteria (high efficiency of resources use, economic rationality, social equity, and ecological security) 19 indices were chosen to evaluate 12 optimizing schemes of four kinds (economic-benefit, food-security, ecological-benefit, and water-saving programs) in 2006, 2020, and 2030. The result shows that, in the 3 years, the water-saving program is always the optimized scheme in an arid region with water deficiency and fragile ecology. The evaluated results match up to the developmental conditions of crop farming in recent years. Moreover, the direction of the optimal projection could reflect the weight and orientation of indices objectively and accurately.