Question

Draw Nitrogen Cycle and explain it.

Answer 1

Nitrogen cycle:

1. Atmospheric nitrogen cannot be directly used by animals and plants.
2. They are fixed by nitrogen-fixing bacteria and converted into a usable form. E.g. Rhizobium
3. The nitrogen cycle is a process in which plants transform atmospheric nitrogen into nitrates, nitrites, and ammonia molecules.
4. Plants provide the nitrogen that animals require.
5. The nitrogen cycle consists of four steps: nitrogen fixation, ammonification, nitrification, and de-nitrification.
6. Nitrification is the process by which ammonia is converted to nitrites (NO₂^-) and then to nitrates (NO₃^-).
7. It has done by rhizobium bacteria.
8. Then the ammonia converts into nitrites and nitrates by nitrification.
9. First nitrite (NO₂) is formed by oxidation of ammonia, and then nitrate (NO₃) is formed.
10. Nitrate is utilized by plants and animals from the soil.
11. The final step is denitrification, where the nitrates are returned to the atmosphere by the action of denitrifying bacteria.
12. When a plant or animal dies, ammonification occurs.
13. Bacteria and fungi, for example, break down the proteins in the organic matter first.
14. This produces ammonia, which dissolves in the soil with water.
15. Ammonia then reacts with a hydrogen ion to form ammonium.