Fig. 1From: Root-associated microbiomes of wheat under the combined effect of plant development and nitrogen fertilizationSoil active carbon (a), soil organic carbon (b), root-released organic carbon (c) and organic acids (d) in the four different N fertilization levels at three growth stages. Error bars indicate the standard deviation of three replicates. Different letters indicate significant differences (P < 0.05) between the N fertilization levels at each growth stageBack to article page