Nitrogen cycle is the cycling of nitrogen and it compound in nature. The following step are used in the cycling.
- Nitrogen fixation, nitrogen is converted into nitrates for plant use through biological and non biological nitrogen fixation.
- Absorption by plants, plants absorb nitrate ions directly from soil and make amino acids/plants proteins.
- Feeding, animals on plants proteins and assimilate them to form animals proteins.
- Ammonification/death and decay, when animals and plants die they are acted upon by saprophytic bacteria and fungi to form ammonia compound.
- Nitrification, ammonia compound are converted into nitrites by nitrifying bacteria e.g nitrosimonas and nitrococcus.
- Denitrification, nitrates in the soil are converted into nitrites, ammonia or free nitrogen gas by denitrifying bacteria e.g pseudomonads and thiobacillus denitrificans. Denitrification deprives soil or fixed nitrogen gas and release free nitrogen into air