Question

What is biological fixation? How is it different from nitrification? Give examples of organisms involved in each of these.

Answer 1

Hint: When the nitrogen-fixing bacteria is present in symbiotic relationships with the host then it is called symbiotic nitrogen fixation. It is usually helpful to plants such as legumes for fixing atmospheric nitrogen gas to ammonia. It is established broadly in nature and has very low economic and environmental costs.

Complete Answer:
The biological nitrogen fixation is usually defined as the process that converts atmospheric nitrogen into the nitrogenous compounds of living organisms is called symbiotic nitrogen fixation.
Most of the microorganisms partner themselves with host plants to fix nitrogen symbiotically. By the process of photosynthesis, plants provide sugars that are utilized by nitrogen - fixing microorganisms for producing energy that is necessary for nitrogen fixation.
Nitrification is usually defined as the process by which ammonium salts are converted into nitrates and nitrites into nitrates. In agriculture, irrigation with dilute ammonia solutions results in soil nitrates increasing through the action of nitrifying bacteria. Nitrifying bacteria convert the smallest form of nitrogen in the soil, ammonia, into its most oxidized form, nitrate. It is done in two stages, such as the formation of nitrite and the formation of nitrate.
Now let us see difference between both of them:

Sl.No	Biological fixation	Nitrification
1.	It is defined as the process of nitrogen fixation in which nitrogen is converted into ammonia or ammonium ions	It is the process or step in the nitrogen cycle in which ammonia is converted into the nitrate.
2.	The end product, maybe ammonia or ammonium ions.	The end product is usually nitrate or nitrite.
3.	This process converts stable nitrogen into the unstable form of nitrogen in the soil.	This process is used to produce assessable nitrogen that is essential to plants.
4.	Microbes used are Azotobacter and Rhizobium	Microbes used are Nitrosomonas and Nitrobacter

Note: The Rhizobium or Brady rhizobium bacteria inhabit the host plant's root system and make roots to form nodules to house the bacteria. The bacteria then start to fix the nitrogen necessary for the plant. Access to the fixed nitrogen allows the plant to make leaves fortified with nitrogen that can be recycled all over the plant.