The effect of elevated air humidity on soil bacterial community in silver birch stand growing in an experimental free air humidity manipulation acility. FAHM

The effect of elevated air humidity on silver birch (Betula pendula Roth.) stand top soil microbial community structure was assessed in a free air humidity manipulation facility (FAHM). The bulk and rhizosphere soil bacterial community structure was analysed using massively parallel sequencing of 16S rRNA gene fragment from V6 hypervariable region. The same 16s rRNA gene fragment was quantified in bulk soils and a denitrification potential of the soil bacterial communities was assessed by the proportions of nitrite reductases encoding nirS and nirK genes, and nitrous oxide reductases encoding nosZ (clade I and clade II) genes using quantitative PCR (qPCR) technique. The results of the statistical analyses revealed that soil chemical conditions were changed in humidified plots soils compare to control plots. Significant differences in bacterial community structure between control and fumigated plots bulk and rhizosphere soils were also found but the changes were more pronounced in rhizosphere.