Nitrogen cycle:

The nitrogen cycle gives to the movement of nitrogen through the food chain of living organisms. This difficult cycle includes plants, bacteria and animals.   All   organisms   can   convert   ammonia (NH₃)   to   organic   nitrogen compounds which is compounds containing C-N bonds.  Moreover, only a few microorganisms can synthesize ammonia from nitrogen gas (N₂). While N₂ gas makes up about 80 percent of the earth's atmosphere and it is a chemically unreactive compound.  The  first  phase  in the  nitrogen  cycle  is the  reduction  of N₂   gas  to ammonia,  a procedure known as nitrogen fixation. Ammonia can also be acquired through reduction of nitrate ion (NO ^-) that is present in the soil. Nitrate decrement can be carried out through most microorganisms and plants.  Through all organisms the ammonia resulting from these two procedures can then be assimilated.  Within the biosphere  there  is  a  balance  among  total  inorganic  and  total  organic  forms  of nitrogen. The translation of organic to inorganic nitrogen comes about through denitrification, catabolism and decay.