Zinc-nitrogen co-fertilization influences N2O emissions and microbial communities in an irrigated maize field

•Several Zn sources (with or without N) were tested on an irrigated maize crop under semi-arid climate.•Zn fertilization increased N2O and respiration fluxes in comparison to urea alone.•Zinc fertilization produced a detrimental effect on nitrifying and denitrifying communities.•Greater effect of Zn sources on NosZ communities compared to other denitrifying genes was found.•The zinc sulphate but not the synthetic chelate increased Zn concentration in grain.