摘要：Drained agricultural peat soils are significant sources of carbon dioxide (CO2) but also small sinks for methane (CH4). Leaving these soils without any cultivation practice could be an option to mitigate GHG emissions. To test this hypothesis, we measured, over a three year period, net CO2 exchange and fluxes of CH4 for five agricultural peat soils that had been abandoned for 20–30 years. Annually, the sites were either small net sinks or sources of CO2 and CH4 (–7.8 to 530 g CO2-C m–2 and –0.41 to 1.8 g CH4 m–2). Including N2O emissions from our previous study, the net (CH4 + CO2 + N2O) emissions as CO2 equivalents were lower than in cultivated peat soils and were lowest in the wet year. Therefore, high GHG emissions from these soils could be avoided if the water table is maintained close to the soil surface when photosynthesis is favoured over respiration.
