Explain nitrogen cycle its own words

The process of circulation of nitrogen between the atmosphere, soil, plants and animals is called the nitrogen cycle. Atmospheric nitrogen is fixed by biological nitrogen fixers as well as through physical processes such as lightning.

Nitrogen Fixation during Lightning

• During lightning, nitrogen and oxygen from the atmosphere combine together and form nitrogen oxides. These gases react with rainwater to form dilute nitric acid. The nitric acid then reacts with minerals present in the soil to form nitrates.
• Plants take in nitrates from the soil through their root system and convert them into proteins. Animals consume these plants and the proteins then enter into their bodies indirectly.
• When plants and animals eventually die, the nitrogenous compounds present in their bodies are broken down into ammonia. This process is known as ammonification.
• Ammonia is converted to nitrates by nitrifying bacteria such as Nitrosomonas and Nitrobacter through a process called nitrification.
• Nitrates may be stored in the form of humus, or they can be leached from the soil and carried to lakes and reservoirs.
• Nitrates can also be converted to free molecular nitrogen by denitrifying bacteria such as Pseudomonas through a process called denitrification and returned to the atmosphere.
• Due to constant recycling of nitrogen, the percentage of nitrogen in the atmosphere remains more or less constant.