Emissions of CO2, N2O and CH4 From Cultivated and Set Aside Drained Peatland in Central Sweden

Örjan Berglund,Katharina H E Meurer,Thomas Kätterer

doi:10.3389/fenvs.2021.630721

Örjan Berglund, Katharina H E Meurer + Show 1 more

Open Access

https://doi.org/10.3389/fenvs.2021.630721

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Abstract

Northern peatlands are important carbon (C) reservoirs, storing about one-third of the global terrestrial soil C pool. Anthropogenic influences, such as drainage for agriculture and forestry, lower the originally high groundwater level, leading to peat aeration and decomposition. This is particularly reflected in significant losses of CO2, while fluxes of N2O and CH4 are generally considered of minor importance for the overall greenhouse gas (GHG) balance of cultivated peatlands in Scandinavia. Setting land aside from agricultural production has been proposed as a strategy to reduce GHG emissions from drained peatland, restore natural habitats, and increase C sequestration. However, the evidence for this is rather scarce unless drainage is terminated. In this study, we measured respiration using dark automatic chambers, and CO2, N2O, and CH4 fluxes using manual static chambers, on: 1) cultivated peatland and 2) adjacent set-aside peatland in Central Sweden. The set-aside site was found to be a greater source of respiration than the cultivated site, while higher N2O fluxes and lower CH4 uptake rates were observed for the cultivated site. However, to compare the full GHG balance and assess the abandonment of drained cultivated peatland, additional measures, such as gross primary production (GPP) but also dissolved organic C losses would have to be taken into account.

Highlights

During the Holocene, northern peatlands stored large amounts of carbon (C) (Yu et al, 2009)
Large areas of peatland are subject to anthropogenic influences and, according to Joosten and Clarke (2002), up to 20% of total global peatland area has been drained for agriculture and forestry
It can be assumed that the original peat layer, i.e., before drainage of the area in 1878 (Nerman 1898), was much thicker and that the peat surface was at higher elevation

Summary

Introduction

During the Holocene, northern peatlands stored large amounts of carbon (C) (Yu et al, 2009). In combination with the naturally high organic C concentration in peat soil, leads to increased C losses in the form of CO2 emissions (e.g., Joosten and Clarke, 2002; Lohila et al, 2004; Joosten 2009; Frolking et al, 2011; Salm et al, 2012; Ballantyne et al, 2014). These highly elevated CO2 emissions persist for decades after drainage of peat soil (e.g., Koizumi et al, 1999; Lohila et al, 2003). The global potential of peatland restoration in reducing GHG emissions is estimated to be very high, 0.31–3.38 Gt CO2-equivalents according to Leifeld and Menichetti (2018)

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