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.