Figure 1

Abundance of bacteria as indicated by the numbers of 16S rDNA copies measured using quantitative PCR. sCK, sN1 and sN2 indicate different N treatments in the soybean season; wCK, wN1 and wN2 indicate different N treatments in the wheat season. The ‘r’ indicates Pearson’s correlation coefficient between N added and 16S rDNA copies (**P < 0.01, *P < 0.05).