Soil chemistry influences microbial communities and nitrogenase gene abundance in the rhizospheres of Miscanthus X giganteus and Panicum virgatum
Results/Conclusions: Multivariate statistical analyses of these data show that while bacterial and diazotrophic endophytic communities differed substantially between plant species, site-to-site variation predominated differences between rhizosphere communities. nifH abundance in the rhizosphere was positively correlated with abundance of ammonia and bioavailability of iron in the soil but negatively correlated with abundance of other soil nutrients including total nitrogen and nitrates. Indicator species analysis revealed enrichment of Proteobacteria, specifically Deltaproteobacteria, in sites with greater nifH abundance. This study demonstrates that associative diazotrophs could contribute to the sustainability of bioenergy feedstock production by enhancing nitrogen availability in low-fertility soils, especially with improved iron bioavailability via site selection and/or soil amendments.