What is the potential to improve food security by restructuring crops in Northwest China?

Exploring the potential of crop type adjustment to improve regional food security, ecological security and net economic benefits is significant for agricultural water management, green production and sustainable development in drylands. Previous studies on the optimization of crop type were mostly concentrated within the region, without considering the impact of interregional food trade on the adjustment of regional crop type. It is difficult to give full play to the advantages of crop type optimization in improving regional food security. This paper introduces the virtual water trade theory into the optimization model of crop type. By quantifying the water footprint, carbon footprint, crop calories and net economic benefits of food crops in Northwest China and Central Asia. On the basis of fully considering farmers' planting willingness in Northwest China and food trade with Central Asian, the relative and absolute comparative advantage index is used as the optimization coefficient of the model. The food security and ecological security of the region, the blue water use efficiency, the green water ratio and the net food efficiency of the provinces (districts) in the region were used as objective functions to construct an open-ended crop type optimization model to optimize the crop type in the region. The results showed that the use of the constructed open crop type optimization model to guide regional food crop type adjustment increased the calories and grey water footprint provided by regional crops by 7.5% and −6.6%, respectively. The provinces in the region have seen varying degrees of improvement in the benefits of blue water use and net economic benefits, particularly in Gansu Province, which have increased by 51.0% and 53.5%, respectively. Due to the effect of crop type adjustment on the regional green water footprint and carbon footprint targets is less than satisfactory. On this basis, effective suggested measures to improve the efficiency of crop green water use and reduce the carbon footprint were proposed. In this study, the combination of relevant measures and grain crop type adjustment can give full play to the role of grain crop type adjustment in alleviating regional water resources and ecological pressure, improving food security, ecological security and sustainable grain production. It is expected to ensure global food security and promote green production and sustainable development of crops.