Managing nitrogen to achieve sustainable food-energy-water nexus in China

Nitrogen holds a crucial place in maintaining the sustainability of the food-energy-water (FEW) nexus, essential pillars underpinning human society. Its vital role spans across food production, energy generation, and the preservation of water quality. Here based on CHANS model, we show that comprehensive nitrogen management strategies offer the dual benefits of satisfying China's food requirements and boosting nitrogen energy production from straw by 1 million tonnes (26%) compared to the baseline year of 2020. Simultaneously, these strategies could lead to a reduction of 8 million tonnes (-31%) in nitrogen fertilizer usage, a decrease of 3.8 million tonnes (-46%) in nitrogen-induced water pollution, and a halving of water consumption in agriculture, all relative to 2020 levels. These transformative changes within the FEW nexus could result in national societal gains of around US$140 billion, against a net investment of just US$8 billion. This emphasizes the cost-effectiveness of such strategies and highlights their significant potential in assisting China to meet multiple sustainable development goals, especially those related to hunger relief, clean energy advancement, and the protection of aquatic ecosystems.