Yield- and protein-neutral reduction in fertilizer rate for wheat, maize and rice can reduce the release of reactive nitrogen and greenhouse gas emissions in China

Abstract Seeking food security, contemporary Chinese agriculture has followed a trajectory of overfertilization and associated environmental problems, hence the need for nitrogen-balancing practices that do not compromise yield quality. Here we present national meta-analysis using 224 studies with 1972 comparisons to quantify potential reduce nitrogen (N) fertilization improve outcomes while maintaining grain protein. We calculated reduction ratio (NRR), as 100 × ( N C − T )/ ; where is fertilizer rate subscripts indicate farmer practice (C) reduced treatment (T). Our showed NRR maintained protein content at level current was up 10% in wheat 30% maize rice. Larger yield-neutral could be achieved more fertile, heavier-textured soils, including enhanced-efficiency fertilizer, combined application organic inorganic incorporated straw. Assuming usage by rice cropping area, there save 5.7 Mt yr −1 loss reactive 1.26 , equivalent 63% annual total Nr losses China, N-related greenhouse emissions 75.2 CO 2 -eq 14.5%–25% chain China; use efficiency 23%. results highlight feasibility protein, achieving substantial benefits rate, agronomic scenarios these are likely.