Soil bacterial community of different grazing intensities under warming and fertilization in Northern Norway (Raisduoddar OTCF grazing experiment)

In this study we tested how four years of experimental warming and fertilization affected soil bacterial communities in subarctic mountain tundra areas with decadal history of either heavy or light reindeer grazing. The study consisted of eight replicates of control (C), warming (W), fertilization (F) and combined warming and fertilization (WF) treatments under two contrasting long-term grazing regimes (light (LG) and heavy (HG) grazing, respectively). Warming was implemented with open-top chambers (OTCs) set to the plots from June to July, and fertilization by adding ammonium nitrate solution (NH4NO3, equivalent to 10 g N m-2) to the plots early in the growing season each year. In July 2013, composite soil samples were collected from the organic horizon, homogenized, and characterized for bacterial community composition in duplicate samples using Ion Torrent high-throughput sequencing of 16S rDNA gene region.