Secondary Successional Forest Soil Bacterial Community Variation Correlates to Soil Type

This study investigated the factors affecting bacterial diversity in purplish and calcareous soils under the same vegetation type. The results showed that obvious differences in pH, water content, total phosphorus (TP), free iron oxide (Fe d ) and amorphous iron oxide (Fe ox ) existed between the two soils. The bacterial Shannon indexes of the two soils varied significantly, and Shannon index of purplish soil were higher than that of calcareous soils. The co-occurring network structures in two soil bacterial communities showed obvious variations, with higher edge counts, average degrees and clustering coefficients in calcareous soils than that in purple soils. The key species group identified in the two soils was Acidobacteria; belonging to the family Thermoanaerobaculaceae in purplish soil, and to the family Vicinamibacterales in calcareous soil. Also, the results of multivariate stepwise linear regression showed that Fe ox was a significant explanatory factor for changes in bacterial diversity (68.8%, P