Optimization of agricultural soil and water resources under fuzzy and random uncertainties: Synergy and trade-off between equity-based economic benefits, nonpoint pollution and water use efficiency

Population growth and the decreasing amount of available soil and water resources have highlighted the importance of integrated allocation of agricultural soil and water resources (IASW). An uncertainty-based multiobjective optimization model for the simultaneous allocation of agricultural soil and water resources (abbreviated as the UASWEEI model) was developed. The economic objective of the UASWEEI model was characterized by an economic benefits function linked with equity, comprehensively reflecting economic, social and ecological dimensions. The environmental objective was to reduce the discharge of agricultural pollutants from carrier areas and soil with an input-output model. The resource use objective balanced the conflicts be-tween water savings and yield increases through an irrigation water use efficiency function (IWUE). The UAS-WEEI model reflected the management uncertainty in IASWs through intuitionistic fuzzy numbers (IFNs) and quantified the stochastic uncertainty in the water supply through Bayesian networks (BNs) combined with climate change scenarios. A fuzzy mathematical method with an optimistic-pessimistic-mixed view was employed to solve the model. The results indicate that (1) the water use structure was adjusted compared with the status quo, and the water-saving effect was dramatic, with the optimized groundwater volume being 49.05 % smaller than the planned groundwater volume. The optimal IWUE is higher than that under the status quo and planning scenarios. (2) The model increases the equity of IASW while balancing the economic-environmental -resource use efficiency, as shown by the 25 % decrease in the Gini coefficient and the 5 % decrease in the Thiel index value compared with the status quo. The study area transitions from a state of inequitable resource allocation to a state of relative equity. This study helps promote the sustainable development of irrigation areas from the perspective of the allocation of water and soil resources.

Automated summary

An uncertainty-based multiobjective optimization model was developed for the allocation of agricultural soil and water resources. The model achieved good results in terms of economics, environment, and resource utilization, and helped promote the sustainable development of irrigation areas.