Fig. 4

The linkage of soil microbial communities and environmental variables. (a). Canonical correspondence analysis (CCA) of soil microbial communities and environmental variables based on GeoChip data, (b) Multivariate regression tree (MRT) of soil microbial communities associated with three sampling sites. The units of available N and plant diversity were mg/kg and 1; n, 421000 (898000 and 301000) represented the sample number and relative error, respectively