Approaches to enhancing grain yield and carbon neutrality with organic and inorganic fertilizer practice in Chinese paddy fields

Achieving both high yield and carbon (C) neutrality, which is critical for food security while pursuing the goal of C neutrality, is often conflicting, particularly with organic fertilizer practices in Chinese paddy fields. Resolving this conflict requires further research and practical changes, as current studies remain fragmented. Therefore, this study used the Denitrification-Decomposition model to evaluate the potential of inorganic and organic fertilizers practices for improving both C neutrality and grain yields in Chinese paddy fields. The findings showed that in chemical nitrogen (N) treatments, grain yield and C neutrality ranged from 6.36–9.48 t ha−1 and 3.49–13.42 t C ha−1, respectively. Specifically, when chemical N was applied at 150–250 kg N ha−1, higher plant C sequestration was observed, leading to increased yield and C neutrality. When chemical N was combined with green manure, straw incorporation, or manure fertilizer, grain yield improved by about 7%, while C neutrality decreased by 20%. To further enhance yield and C neutrality, it is imperative to increase plant C sequestration by 1.0 t C ha−1 and reduce N2O emission by 0.22 t CO2-eq ha−1 in chemical N applications of 150–200 kg N ha−1 combined with green manure. Additionally, achieving higher C neutrality with chemical N applications of 200–250 kg N ha−1 combined with straw incorporation or manure fertilizer requested enhancing plant C sequestration by 1.2 t C ha−1 or reducing the global warming potential. In conclusions, combining chemical N at 150–200 kg N ha−1 with green manure offers a promising approach to achieving both higher grain yield and C neutrality. However, efforts to further reduce carbon emissions are still essential for enhancing C neutrality. The study provides valuable insights for advancing food security while pursuing the goal of C neutrality in Chinese rice fields. Graphical abstract