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Research article - Peer-reviewed, 2007

Nitrous oxide emissions from drained organic forest soils - an upscaling based on C:N ratios

Ernfors M, von Arnold Karin, Stendahl Johan, Olsson Mats, Klemedtsson Leif


Total emissions of N2O from drained organic forest soils in Sweden were estimated using an equation linking the C:N ratio of the soil to N2O emissions. Information on soil C:N ratios was derived from a national database. It was estimated that the emissions from Histosols amount to 2,820tonnes N2O a−1. This is almost five times the value calculated for the same soils using the method suggested by the Intergovernmental Panel on Climate Change: 580tonnes N2O a−1. The higher value in the present study can mainly be explained by improved accuracy of estimates of N2O emissions from nutrient-rich soils, including former agricultural soils. In Sweden, in addition to 0.94Mha of drained Histosols, there are 0.55Mha of other types of drained organic soils. The annual emissions from these soils were estimated to amount to 1,890tonnes of N2O. The total emission value calculated for drained organic forest soils was thus 4,700 tonnes N2O a−1, which, if added, would increase the current estimate of the Swedish anthropogenic N2O source strength by 18%. Of these emissions, 88% occur from sites with C:N ratios lower than 25. The exponential relationship between C:N ratio and N2O emissions, in combination with a scarcity of data, resulted in large confidence intervals around the estimates. However, by using the C:N ratio-based method, N2O emission estimates can be calculated from a variable that is readily available in databases. Also, the recent findings that there are exceptionally large emissions of N2O from the most nitrogen-rich drained organic forest soils are taken into account.

Published in

2007, volume: 84, number: 2, pages: 219-231

Authors' information

University of Gothenburg
von Arnold, Karin
Swedish University of Agricultural Sciences, Department of Forest Soils
Olsson, Mats
Swedish University of Agricultural Sciences, Department of Forest Soils
Klemedtsson, Leif

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use

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