what is nitrogen cycle and processes involved in it?? decribe the processes also.

what is nitrogen cycle and processes involved in it??
decribe the processes also.


4 Answers

25750 Points
4 years ago

Nitrogen cycle consists of four main steps namely:

  1. Nitrogen Fixation
  2. Ammonification/ Decay
  3. Nitrification
  4. De-nitrification

It is important to note that microorganisms play an important role in each of these steps.

What is the mechanism of each of these steps?

Nitrogen Fixation

This is the first step of the nitrogen cycle. This step is characterized by the conversion of atmospheric N2 into ammonia (NH3). Bacteria like Azotobacter and Rhizobium have a major role in this process. They are harbored in the roots of the leguminous plants and help convert inert nitrogen to ammonia. Nitrogen fixation can occur in any of the following ways: atmospheric fixation (involves lightening), industrial fixation(manufacturing ammonia under high temperature and pressure condition)


Once the nitrogen has been fixed in the soil, plants can absorb nitrogen through their roots. This process of absorption is known as assimilation.


This is another process by which ammonia can be generated. Organic remains of plants and animals are broken down in the soil by some bacteria to release ammonia into the soil. These dead and waste matter is used by these microorganisms as food and they release ammonia into the soil.


This occurs in two-steps. The first step is in which NH3/NH$+ is converted to NO3- (nitrates). The bacteria Nitrosomonas and Nitrococcus present in the soil convert NH3 to NO2-, and another bacterium, Nitrobacter converts NO2- to NO3-. These bacteria gain energy through these conversions.


Is the reverse of nitrification that occurs in the deep layers of soil where the bacteria convert NO3- is converted into N2 and other gaseous compond like . This occurs because in deep layers of soil, oxygen is not available and the soil bacteria use these nitrogen compounds instead of oxygen.

Vikas TU
14149 Points
4 years ago
Dear student 
Please refer the olowing link 
Hope this helps 
Good Luck 
Parishkrit Parashar
36 Points
3 years ago
  • Everything in nature is in a cyclic form, so that it is replenished and used. Nitrogen cycle is a cycle, in which nitrogen is circled on the earth, for the sustenance of life, the process involved in nitrogen cycle are as follows:-


  • (i)Nitrogen fixation-Atmospheric nitrogen must be processed, to be used by plants.

  • (ii)Assimilation-Plants can absorb nitrate or ammonia from the soil via their root hairs. If nitrate is absorbed, it is first reduced to nitrite and then ammonia.

  • (iii)Ammonification-Bacteria, or fungi in some cases, convert the organic nitrogen into ammonium, a process called ammonification.

  • (iv)Nitrification-Conversion of ammonia to nitrate is performed primarily by soil-living bacteria and other nitrifying bacteria.

  • (v)Denitrification- Denitrification is the reduction of nitrates back into the largely inert nitrogen gas, completing the nitrogen cycle which is performed by Clostridium in anaerobic conditions.

908 Points
3 years ago
When nitrogen is absorbed by the soil, different bacteria help it to change states so it can be absorbed by plants. Animals then get their nitrogen from the plants. Fixation - Fixation is the first step in the process of making nitrogen usable by plants. ... They absorb nitrates from the soil into their roots

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