Nitrous oxide (N2O) is one of the most important greenhouse gases and its main source is agricultural soils. Soil microorganisms regulate N2O production and consumption, the latter being limited to microorganisms able to express the nitrous oxide reductase gene (nosZ). Recent studies have identified two distinct clades of nosZ carrying microorganisms, nosZI and nosZII, nosZII being previously uncharacterized. This study assessed how different agricultural practices affected these two nitrous oxide reducer clades as well as N-gas production by denitrification. The nosZI and nosZII communities responded differently to environmental variables, nosZII clade being more sensitive to environmental changes. nosZII diversity was the major factor explaining the proportion of N2O emitted from various arable farming systems. This finding highlights the importance of understanding the ecology of this newly identified clade of N2O reducing microorganisms for mitigation strategies. Overall, our results suggest that changes in agricultural practices can potentially shift the N2O-reducing community with consequences for the N2O emissions.
Published 22. May 2015 - 14:09 - Updated 2. June 2015 - 12:45