Degradation of cultivated peat soils in northern norway based on field scale CO₂, N₂O and CH₄emission measurements

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.