Nitrogenous materials are substances obtained from conversions of nitrogen during its cycle through an interaction with various media aquatic, terrestrial and air. In a pond, for example, micro-organisms (cyanobacteria and bacteria) live symbiotically with plants which promote conversion of nitrogen to ammonium. Similarly, some bacteria cause nitrification, an oxidation reaction which converts it into nitrites (NO2-) and then into nitrates (NO3-) which can be assimilated by plants.
Ponds often contain nitrogenous materials. © DR