Soil characteristics more strongly influence soil bacterial communities than land-use type.

To gain insight into the factors driving the structure of bacterial communities in soil, we applied real-time PCR, PCR-denaturing gradient gel electrophoreses, and phylogenetic microarray approaches targeting the 16 S r RNA gene across a range of different land usages in the Netherlands. We observed that the main differences in the bacterial communities were not related to land-use type, but rather to soil factors. An exception was the bacterial community of pine forest soils ( PFS), which was clearly different from all other sites. PFS had lowest bacterial abundance, lowest numbers of operational taxonomic units ( OTUs), lowest soil p H, and highest C : N ratios. C : N ratio strongly influenced bacterial community structure and was the main factor separating PFS from other fields. For the sites other than PFS, phosphate was the most important factor explaining the differences in bacterial communities across fields. F irmicutes were the most dominant group in almost all fields, except in PFS and deciduous forest soils ( DFS). In PFS, A lphaproteobacteria was most represented, while in DFS, F irmicutes and G ammaproteobacteria were both highly represented. Interestingly, B acillii and C lostridium OTUs correlated with p H and phosphate, which might explain their high abundance across many of the Dutch soils. Numerous bacterial groups were highly correlated with specific soil factors, suggesting that they might be useful as indicators of soil status. [ABSTRACT FROM AUTHOR]