基于复杂种植结构多情景分析的灌区多目标多水源优化配置

为改善多水源灌区农业用水供需矛盾,通过合理调整种植结构,优化灌区水资源配置,该研究以河北省邯郸市漳滏河灌区为研究对象,将农业灌溉缺水量最小和农作物经济效益最大作为目标函数,兼顾灌区生态安全约束,构建了基于种植结构优化的多目标多水源优化配置模型,针对作物熟制、作物种类、种植制度以及灌溉方式设置了8种不同的种植结构优化情景,通过自主改进的基于精英策略并协遗传算法（NSGAⅡ-S）对模型求解,获得不同情景下的水资源优化配置方案。结果表明：应用模型进行水资源配置后,各情景配水总量均有所减少,其中水库配水量高于其他水源的配水量,水库水、引黄水和引江水均达到用水总量控制目标,民有分区的各计算单元间的配水量变化明显,总配水量高于滏阳河分区;适当压减主要依靠抽取地下水灌溉的冬小麦的播种面积,变灌溉农业为旱作雨养农业,可以极大地减少地下水用量,增加灌区经济效益;最佳的种植结构优化方案为CS₄（削减冬小麦的种植面积,种植苜蓿,灌溉方式采取管灌或喷灌）,该方案冬小麦播种面积压减17.10%,地下水开采量减少了16.42%,灌区的经济效益增加了26.41%,在保证配水总量最小的同时,具有更高的经济效益。该研究所构建的多目标多水源优化配置模型和作物配水结果可为类似地区的水资源配置提供参考。

Multi-objective and multi-source irrigation area based on multi-scenario analysis of complex planting structure

Under the combined influence of global climate change and economic and social development, the contradiction between supply and demand of water resources has become increasingly prominent, and agricultural water use is facing serious challenges. Reasonable adjustment of planting structure and optimal allocation of agricultural water resources are the key ways to ensure regional agricultural water demand. In order to improve the contradiction between supply and demand of agricultural water in irrigation areas and scientifically optimize the allocation of water resources in irrigation areas, this study took the Zhangfu River irrigation area in Handan City, Hebei Province as the research object, the minimum water shortage of agricultural irrigation and the maximum economic benefits of crops as the objective functions, and took into account the ecological security constraints of the irrigation area. A multi-objective and multi-water source optimal allocation model based on planting structure optimization was constructed. Eight different planting structure optimization scenarios were set for cropping system, crop type, planting system and irrigation method. The model was solved by the self-improved elite strategy and co-genetic algorithm (NSGAⅡ-S) to obtain the optimal allocation of water resources under different scenarios. The results showed that after the application of the model to optimize the planting structure, the reservoir water and the river water can be supplied to the downstream units of the private partition. The groundwater exploitation of each calculation unit was significantly reduced, and the water distribution between the calculation units of the private partition was obvious. The total water distribution was higher than that of the Fuyang River partition. The proportion of reservoir water distribution and groundwater water distribution in different scenarios was relatively stable and was used in each month. The water distribution of the Yellow River was mainly concentrated in the summer of the peak period of water use, and the use of reservoir water and river water was more in winter. Appropriate reduction mainly depended on the planting area of winter wheat irrigated by groundwater extraction. Changing irrigated agriculture to rain-fed agriculture greatly reduced the amount of groundwater and increased the economic benefits of irrigation areas. The best planting structure optimization scheme was CS₄. In this scheme, the planting area of winter wheat was reduced by 17.10%, the groundwater exploitation was reduced by 16.42%, and the economic benefit of the irrigation area was increased by 26.41%. While ensuring the minimum total water distribution, it had higher economic benefits. The multi-objective and multi-water source optimal allocation model of the irrigation area constructed in this study comprehensively considered the agricultural irrigation water consumption and economic benefits of the irrigation area, clarified the water supply relationship of each sub-unit, and explored the planting structure of the irrigation area and the optimal allocation of water resources under the goal of groundwater exploitation. The new model gave full play to the rational allocation of water resources in the irrigation area and provided a decision-making basis for the planning and management of water resources in the irrigation area. The research results are helpful to give full play to the water source advantages of the irrigation area, provide an example for the optimal allocation of water resources in similar areas, and provide theoretical basis for ensuring food security and sustainable development of agricultural economy.