Correlation analysis of bacterial and fungal phyla with significantly differential metabolites.The asterisks (*, **, ***) represent the level of significance, where * indicates p ≤ 0.05, ** indicates p ≤ 0.01, and *** indicates p ≤ 0.001. (a) Correlation between bacterial phyla and significantly differential metabolites in bulk soil. (b) Correlation between fungal phyla and significantly differential metabolites in bulk soil. (c) Correlation between bacterial phyla and significantly differential metabolites in rhizosphere soil. (d) Correlation between fungal phyla and significantly differential metabolites in rhizosphere soil. Horizontal axis displays significantly differential metabolites (with some shown as abbreviations), while vertical axis represents microorganisms (ten most abundant phyla). Red indicates positive correlation, and green indicates negative correlation. 1,2-Dipalmitoyl-sn-glycero-3-phospho(1′-rac-glycerol) (DPPG).