Evolution and optimization of potato cultivation layout in China from a perspective of water-carbon-food nexus

[Objective] Potatoes are the fourth largest staple crop in China. Therefore, achieving increased production, water saving, and carbon reduction is of key importance to guarantee sustainable potato production in China. Achieving multi-objective synergy through spatial layout optimization is an important issue requiring urgent research. [Methods] Using provincial panel data from 2008 to 2022, this study applied the life cycle method and the standard Penman-Monteith formula to measure carbon emissions and water consumption per unit yield in potato production. The standard deviation ellipse model was employed to analyze the evolution of potato cultivation layout and the accompanying characteristics of water consumption and carbon emissions. Furthermore, the advantages of potato cultivation were examined in China's 24 provinces based on the production advantage index, water-saving advantage index, and carbon-saving advantage index. Strategies were proposed to optimize the future spatial layout of potato cultivation in China. [Results] (1) China's potato cultivation layout showed a continuous trend toward concentration in the southwestern region, and the evolution of the spatial layout was accompanied by characteristics of high water consumption and high carbon emissions over the long term. (2) High-production provinces such as Guizhou, Yunnan, Hubei, Shanxi, Shaanxi, and Gansu were spatially mismatched with provinces having strong low-carbon and water-saving advantages, and high-production provinces did not simultaneously possess water-saving and low-carbon production advantages. Potato cultivation in water-scarce regions such as Hebei, Shanxi, Liaoning, Gansu, and Ningxia further increased pressure on regional water resources. (3) Only Chongqing and Sichuan had integrated production, water-saving, and carbon-saving advantages under the existing pattern, while the remaining 22 provinces did not simultaneously possess production, water-saving, and carbon-saving advantages in potato cultivation. [Conclusion] The existing potato cultivation layout cannot deliver the synergy of yield increase, water conservation, and carbon reduction. It is suggested to optimize the spatial layout of potato cultivation by reducing the planting area in Hebei, Shanxi, Liaoning, Gansu, Ningxia, and Xinjiang, and increasing the planting area in Heilongjiang, Jilin, Jiangxi, Guangdong, and Inner Mongolia, which is expected to increase potato production by 1.66% to 1.72%, reduce irrigation water consumption by 7.45% to 7.95%, and reduce carbon emissions by 4.32% to 4.62%, so as to achieve a balance between the security of potato supply and resource and environmental protection.