AUTHOR=Norberg Lisbet , Hellman Maria , Berglund Kerstin , Hallin Sara , Berglund Örjan 

TITLE=Methane and Nitrous Oxide Production From Agricultural Peat Soils in Relation to Drainage Level and Abiotic and Biotic Factors

JOURNAL=Frontiers in Environmental Science

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2021.631112

DOI=10.3389/fenvs.2021.631112

ISSN=2296-665X

ABSTRACT=<p>Greenhouse gas emissions from drained agricultural peatlands contribute significantly to global warming. In a laboratory study using intact cores of peat soil from eight different sites in Sweden, factors controlling the emission of the greenhouse gases nitrous oxide (N<sub>2</sub>O) and methane (CH<sub>4</sub>) were examined. Soil properties, and the abundance of the total microbial community (16S rRNA gene abundance), and genes encoding for functions controlling N<sub>2</sub>O emissions (bacterial and archaeal <italic>amoA</italic>, <italic>nirS</italic>, <italic>nirK</italic>, <italic>nosZ</italic>I, and <italic>nosZ</italic>II) were analyzed and compared against measured greenhouse gas emissions. Emissions were measured at different drainage levels, i.e., higher soil water suction values, since drainage is an important factor controlling greenhouse gas emissions from peat soils. The results showed that N<sub>2</sub>O and CH<sub>4</sub> emissions were generally low, except for N<sub>2</sub>O emissions at near water-saturated conditions, for which three soils displayed high values and large variations in fluxes. Relationships between N<sub>2</sub>O emissions and soil properties were mainly linked to soil pH, with higher emissions at lower pH. However, specific assemblages of nitrogen cycling guilds that included <italic>nos</italic>ZII, typically present in non-denitrifying N<sub>2</sub>O reducers, were detected in soils with low N<sub>2</sub>O emissions. Overall, these results indicate that both pH and biotic controls determine net N<sub>2</sub>O fluxes.</p>