Unlocking Potassium Constraints for China's Food Security

Potassium (K), primarily supplied by potash and agricultural solid residues, is essential for crop growth and stable food production. However, inadequate K management poses a threat to food security. In China, potash is designated a strategic mineral due to its agricultural importance, limited domestic reserves, and long-term reliance on imports. Notably, nutrient recycling from agricultural solid residues can help supplement K supply. However, the potential contribution of these residues to national K resources remains underexplored. Additionally, while healthy dietary transitions have garnered increasing attention, the resulting changes in K demand remains unmeasured. Here we present an integrated model that quantifies the impacts of healthy dietary transitions, mineral exploration strategy, and soil nutrient balance strategies on the K supply chain. We find that China is likely to exhaust the present potash reserve within 15 years, and soil K nutrients will continue to be depleted from 2023 to 2050, thereby posing a serious threat to long-term food security. However, coordinated implementation of these strategies could reduce potash import dependency by up to 30.7%, with domestic reserves potentially sufficient to meet future demand. These findings offer critical insights for nutrient management, support efforts to reduce reliance on imported potash, and inform the development of sustainable agricultural and resource policies.