Bacteria converts the ammonia and ammonium into nitrates and nitrites is described below.
Explanation:
1. Nitrifying bacteria convert ammonia to nitrites or nitrates. Ammonia, nitrites, and nitrates are all fixed nitrogen and can be absorbed by plants. Denitrifying bacteria converts nitrates back to nitrogen gas.
2. The nitrification process requires the mediation of two distinct groups: bacteria that convert ammonia to nitrites (Nitrosomonas, Nitrosospira, Nitrosococcus, and Nitrosolobus) and bacteria that convert nitrites (toxic to plants) to nitrates (Nitrobacter, Nitrospina, and Nitrococcus).
3. Nitrifying bacteria present in the soil convert ammonia into nitrite. Nitrite is then converted into nitrate. This process is called Nitrification.
4. De-Nitrification: Nitrogen in its nitrate form (NO3–) is converted back into atmospheric nitrogen gas (N2) by bacterial species such as Pseudomonas and Clostridium, usually in anaerobic conditions. These bacteria use nitrate as an electron acceptor instead of oxygen during respiration