Explain the nitrogen cycle, giving relevant examples.

Nitrogen Cycle :
* Nitrogen cycle described by 5 steps.
* Nitrogen Fixation : The process of conversion of molecular nitrogen into ammonia (or) nitrogen oxides, nitrites and nitrates.
* Nitrogen assimitation : Chemically binding of ${\mathrm{NH}}_4^{+},{\mathrm{NO}}_2^{-}\text{and }{\mathrm{NO}}_3^{-}$ with other elements to
produce organic nitrogen in plants and there by into animals.
* Ammonification : Decomposition of organic nitrogen of dead plants and animals into ammonia by soil bacteria.
Eg : Bacillus
* Nitrification : Ammonia is oxidised to nitrites and nitrates by nitrifying bacteria
Eg : Nitrococcus, Nitrobacter
* Denitrification : Nitrates of soil is reduced to nitrogen by bacteria like Pseudomonas and Thiobacillus.