nitrification nitrification /ˌnaɪtrɪfɪˈkeɪʃən/

noun

1. The oxidation of ammonium compounds in dead organic material into nitrates and nitrites by soil bacteria (making nitrogen available to plants)  ( nitrification )
   the oxidation of ammonium compounds in dead organic material into nitrates and nitrites by soil bacteria (making nitrogen available to plants)
   
2. The chemical process in which a nitro group is added to an organic compound (or substituted for another group in an organic compound)  ( nitrification )
   the chemical process in which a nitro group is added to an organic compound (or substituted for another group in an organic compound)