This invention relates to the fixation of atmospheric nitrogen and the production of nitrates, and consists primarily in subjecting preheated atmospheric air, and superheated steam, while under pressure in a closed chamber, to the action of direct or alternating electric current in the presence of suitable lime compounds, preferably a mixture of hydrate of lime and carbonate of lime, the 1 latter preferably in the form of calc spar, both the lime and spar being in a dry state and reduced to a fine powder or flour. It is found also that the reactions are facilitated or promoted by the presence of a catalyst.