Factors limiting microbial N2O and CO2 production in a cultivated peatland overlying an acid sulphate subsoil derived from black schist

•In black schist AS soils, the respiration profile differs from coastal AS soils.•Peat horizons dominate oxic CO2 and N2O production over mineral subsoil.•Oxic GHG production in subsoil is little affected by NH4+, glucose or temperature.•Anoxic denitrification is limited by nitrate in all but topsoil H1 horizon.•Anoxic denitrification is not limited by available C in any but subsoil Cr horizon.