The effects of site preparation practices on carbon dioxide, methane and nitrous oxide fluxes from a peaty gley soil

Abstract

Summary The effects of site preparation practices (drainage, mounding and fertilization) on the fluxes from the soil surface of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were studied on an organic-rich peaty gley soil at Harwood Forest, north-east England. Drained plots had significantly higher CO 2 fluxes but significantly lower CH4 fluxes compared with undrained plots, while N 2O emissions were not affected by drainage. Mounding caused significantly higher CH 4 emissions, while it significantly reduced N 2O emissions. Fertilization caused significant increases in emissions of CO2, CH4 and N2O. In terms of overall greenhouse warming potential, drainage and fertilization increased CO2-equivalent emissions by ~18−29 and 7−23 per cent, respectively, while mounding reduced CO2-equivalent emissions by ~8 per cent in year 1, but had no effect on emissions in year 2 of study. Soil temperature was the main environmental variable controlling CO2 emissions, while CH4 was controlled primarily by water table depth. Nitrous oxide emissions responded to changes in soil temperature and water table depth. In the short term, drainage and fertilization contributed to accelerating greenhouse gas emissions significantly, although their long-term effects are likely moderated by accelerating carbon accumulation in the tree biomass. Long-term studies are required to assess the cumulative impacts of site preparation practices during the whole rotation cycle.