3.4 Soil bacterial community β diversity
The results of NMDS analysis based on Bray‒Curtis showed that the soil bacterial communities at the genus, family, class and phylum levels showed clear aggregation types in SF, PB and CSF (Fig. 3A, D, H, K). At the class and phylum levels, the distance between SF and PB was not significantly different from that between SF and CSF, both of which were significantly higher than that between PB and CSF (Fig. 3C, F). At the genus and family levels, the Bray‒Curtis distance between the soil bacterial communities of SF and PB was the largest, which was significantly greater than the distance between SF and CSF, and the distance between PB and CSF and the distance between CSF and SF were significantly higher than the distance between CSF and PB (Fig. 3J, M).