PMC

Relative abundance of phyla in the soil bacterial communities in the upper (a) and the lower-layer soils (b) separated according to pH.

nmds plots derived from phylogenetic similarity based on jackknifed unweighted unifrac distances between soil samples, with symbols coded by depth (a) and pH (b).

cart analysis to describe the main properties for the dominant phyla Acidobacteria, Alphaproteobacteria, and Actinobacteria in the upper (a) and the lower-layer soil (b) samples.

Distance-decay analysis of the relationship between geographic distance and bacterial community distance based on jackknifed unweighted unifrac distance in both layers. The slope was significant in the lower-layer soils (P < 0.05; y = −6E−05x + 0.6615, solid line).