A multi-objective optimization for coordinating water-land resources considering crop suitability and drought effects

This study proposes a spatial multi-objective collaborative optimization method for land and water resources, integrating regional crop suitability and drought effects. The method optimizes the spatial distribution of resources, balancing economic benefits and blue water utilization while mitigating the adverse effects of drought on agricultural production. A multi-scale drought evaluation index (MSEDI) is developed to quantify the relationship between drought and crop yield reduction, and crop suitability evaluation is combined with a cellular automaton model to optimize the spatial distribution of land and water resources. A regional grid-based multi-objective planning model is employed to balance economic benefits and resource utilization efficiency. The application in the Sanjiang Plain shows that approximately 4.5 million 100 m× 100 m grid cells were optimized, leading to an increase in the water productivity of rice, maize, and soybeans by 18.3 %, 16.9 %, and 8.8 %, respectively, effectively coordinating land and water resource utilization with crop yield. Additionally, the irrigation strategy was optimized with a trend of "low in the early stage, high in the mid-stage, and reduced in the late stage," which improved the water use structure, shifting the ratio of surface water and groundwater from 63 % and 37–72 % and 28 %, reducing groundwater over-extraction. In drought years, the model reduced economic risk due to drought-related yield loss by 14 % compared to traditional models, validating its applicability in drought conditions. This provides a scientific basis for sustainable agricultural resource management. • Proposes a grid-scale water and soil optimization method considering drought impacts. • Simultaneous crop suitability and irrigation optimization improves water use efficiency. • Grid-based optimization enhances water productivity and addresses drought risks. • Model considering drought cuts economic loss risk by 14 % vs. traditional models.