Question

describe nitrogen cycle in 100 words

Answer 1

 · Nitrogen cycle is the biogeochemical process by which nitrogen is converted into different chemical forms as it circulates in the atmosphere and in the terrestrial and marine ecosystems. The various processes in the nitrogen cycle can broadly be classified as fixation, ammonification, nitrification and denitrification.

Answer 2

Our atmosphere has 78% nitrogen gas.
Certain bacteria and blue green algae present in the soil fix Nitrogen from the air and convert it into compounds of nitrogen. Once nitrogen is converted into these usable compounds ,it can be utilised by plants from the soil through their root system. Nitrogen is then used for the synthesis of plant proteins and other compounds. Animals feeding on plants get these proteins and other nitrogen compounds.
When plants and animals die, bacteria and fungi present in the soil convert the nitrogenous wastes into nitrogenous compounds to be used by plants again. Certain other bacteria convert some part of them to nitrogen gas which goes back into the atmosphere .As a result ,the percentage of nitrogen in the atmosphere remains more less constant.