Equations in Table 1 (NUEdiff = (HNT - HNC) / FN; NUE15N = (HNT × %Ndff) / FN; NUEbala = HNT / (FN + NFN)) were used to estimate the average NUEdiff, NUE15N, and NUEbala for the three major cereal crops within China’s cereal cropping system. Data sources: the average %Ndff was from Supplementary Table 2; HNC was calculated as the product of HNT and the ratio of HNC to HNT which was estimated based on the observed yield response to fertilizer nitrogen input in Supplementary Fig. 4 and the observed nitrogen concentration response to fertilizer nitrogen input in Supplementary Table 5; the average HNT and FN were from Supplementary Table 3; the average NFN was from Supplementary Table 4 (asymbiotic N fixations were estimated as 30 kg N ha−1 for rice, and 10 kg N ha−1 for wheat or maize). See Fig. 1 caption for definitions of abbreviations.