Denitrifiers in the surface zone are primarily responsible for the nitrous oxide emission of dairy manure compost

► Nitrous oxide (N2O) productions of each compost zones were compared. ► The pile surface emitted significant fluxes of N2O. ► The isotopic signature of N2O from surface and NO2− amended core were different. ► The denitrifying gene abundance was significantly higher in pile surface than the pile core.