Contribution of nitrogen to main cereal crops yield and the key drivers in China

Despite the recognized contribution of nitrogen (N) fertilizer to cereal production, the spatial variation and driving factors remain uncertain. This study determined yield response to nitrogen (YRN) across diverse ecological regions using 49,160 site-years of on-farm experiments and identified key drivers and their interactions. Nitrogen contributes 119.7 million tonnes (Mt) to China's production of maize, wheat, and rice, equivalent to 17% of national production in 2023. The average YRN was 1.73 Mg ha(-1), with considerable variation among subregions and land-uses. The top five influential predictors of YRN were estimated, and the most significant interactive factors were evaluated using mix-effect model. For upland crops, solar radiation (SR) significantly inhibits YRN, but this inhibition is modulated by LT through an interactive effect. For paddy rice, evapotranspiration (ET) and SR interacted synergistically, surpassing their individual effects. These results provide benchmarks for optimizing fertilizer strategies and inform effective nitrogen management to enhance agricultural sustainability.