Degradation of cultivated peat soils in northern norway based on field scale CO₂, N₂O and CH₄ emission measurements

Abstract

Peat soils cover 2 – 3% of the total global land area, and store approximately one-third of the soil carbon and as much carbon as stored in the atmosphere. Conversion of natural peatland ecosystems into arable land dramatically increases soil organic matter mineralization, notably because of the required drainage operations. In the present paper, greenhouse gas emissions from cultivated peat soils were measured in Northern Norway. The results show that CO₂ emissions increased with air temperature, while this effect was not clearly observed for N₂O and CH₄ emissions. Estimated net emissions of greenhouse gases from a pipe-drained peatland, expressed in kg of CO₂ equivalent m⁻² yr⁻¹, were about 2.20 kg for CO₂, 0.03 kg for CH₄ and 0.13 kg for N₂O, and the net carbon loss was about 0.6 kg C m⁻² yr⁻¹. Therefore, carbon loss is akin to soil degradation when effects on climate gas emissions are taken into consideration. The results demonstrate the importance of CO₂ emissions from northern cultivated peatlands, which were about 17 times higher than those of N₂O on a CO₂-base equivalence.

Keywords:

• Soil degradation
• peat soils
• greenhouse gas emission

Acknowledgements

The presented results are part of an ongoing EU 5th framework project EUROPEAT (QLK5-CT-2002-01835) on environmental and social aspects with sustainable cultivation of peat soils. Most of the field gas samples were taken by Atle Hauge.