Carbon dioxide fluxes at an intensively cultivated temperate lowland peatland in the East Anglian Fens, UK

Abstract. This study reports the first recorded CO₂ flux measurements of a drained and intensively cultivated lowland peatland in the East Anglian Fens (UK) using the eddy covariance technique. Measurements were made over a complete lettuce crop rotation and a subsequent fallow period. Maximum average daytime CO₂ uptake and nocturnal loss rates were −10.39 and 7.63 μmol CO₂ m⁻² s⁻¹, respectively. Daily CO₂ budgets ranged from a net loss of 4.7 to a small net uptake of −1.23 g CO₂-C m⁻² d⁻¹. Total vertical land/atmosphere CO₂ losses were estimated at 227.11 ± 46.5 g CO₂-C m⁻² for a~120 day measurement period. Losses over a sixty day interval between field preparation and disking of the field at the end of the crop cycle were 74.22 ± 18.8 g CO₂-C m⁻². The site lost 152.89 ± 30.6 g CO₂-C m⁻² d⁻¹ during a sixty day fallow period. Net ecosystem production was estimated at 117.72 ± 18.8 g CO₂-C m⁻² during the crop cycle and 270.61 ± 46.49 g CO₂-C m⁻² for the entire measurement period when harvested crop exports were accounted for. These results represent the first micrometeorological measurements obtained over degraded lowland peatland in Britain, and illustrate the scale of CO₂ losses associated with agricultural production on temperate organic soils.