Assessing the Effects of Land Use On Microbial Diversity and Phylogeny Across a Mixed Culture Agroecosystem.

Land-use change has been shown to have significant impacts on soil conditions and microbial communities alike.  Nonetheless, there has not been many studies to assess the subsequent impacts on microbial communities in relation to soil physical and chemical properties. Replicate soil samples were collected from a demonstration farm in which three land-use types were exhibited (pine forest, cultivated soil, and livestock pasture lands) on a single soil type in Perry County Alabama.  Bacterial-tag encoded FLX amplicon pyrosequencing was used to generate genomic libraries targeting 16S rRNA. Double dendograms were generated according to relative abundance (%) of bacterial taxonomic orders amongst land-use types.  Specific phyla (notably Acidobacteria, Bacteriodetes, Chloroflexi, Verrucomicrobia, and Gemmatimonadetes) showed significant shifts across the land-use strata.  Selected soil properties (SOM, soil texture, pH, and enzyme activity) also differed significantly across land-use types, while showing variation consistent with changes in microbial phyla.   Together these results suggest that pyrosequencing along with traditional analysis of physical and chemical soil properties may be able to provide insight into the evolution of microbial communities across a given landscape.