Nitrous Oxide Dynamics in Agricultural Peat Soil in Response to Availability of Nitrate, Nitrite, and Iron Sulfides

Abstract

Drained agricultural peat soils are potential hot spots of nitrous oxide (N₂O) emissions, but the biogeochemical basis for distinctively large emissions is still unclear. Incubation experiments with acidic bog peat, using nitrate (NO₃⁻), nitrite (NO₂⁻), synthetic iron monosulfide (FeS), and ground natural pyrite (FeS₂), suggested that heterotrophic denitrification of nitrate and nitrite was a major potential source of N₂O in the peat soil. Neither FeS nor FeS₂ amendment affected N₂O production and therefore high production potentials of N₂O were not a result of interactions between N oxyanions and iron sulfides, such as chemolithoautotrophic pyrite oxidation.

Keywords:

• Biogeochemical cycling
• denitrification
• wetland

Acknowledgments

The authors thank Bo Elberling for providing samples of pyrite minerals and Bodil Stensgaard, Karin Dyrberg, and Jørgen Munksgaard Nielsen for skillful laboratory assistance.

Additional information

Funding

This study received financial support from the Danish Research Council [DFF 4005-00448].