Fig. 4

NMDS analysis of the bacterial (A) and fungal (B) communities influenced by different SPSB concentrations. CK (no biochar), S1 (2.5% w/w biochar + soil), S2 (5% w/w biochar + soil), S3 (7.5% w/w biochar + soil). Stress < 0.2, the graph is interpretable; P < 0.05, the difference between groups is significant