Question

what do you mean by nitrogen cycle

Answer 1

Answer:

... nitrogen cycle is process in which nitrogen is taken and addition of Nitrogen also take place in the atmosphere..

Answer 2

$\mathfrak{\large{\underline{\underline{Answer :-}}}}$

• Nitrogen is present in its gaseous form in the atmosphere. The atmosphere contains about 78% nitrogen.

• All living things need nitrogen for their growth and development.

• Gaseous nitrogen cannot be used by living organisms.

• Nitrogen is converted into a form usable by living organisms through the nitrogen cycle.

• The nitrogen cycle is a series of processes in which atmospheric nitrogen is converted into chemical forms usable by plants and animals, and then returned to the atmosphere.

• Bacteria play a very important role in the nitrogen cycle.

• Nitrogen fixation, nitrification, nitrogen assimilation, ammonification and denitrification are five main processes of the nitrogen cycle.

★ $\textbf{\small{\underline{Nitrogen Fixation :}}}$

• Conversion of nitrogen gas into biologically available inorganic nitrogen such as ammonia, nitrites and nitrates is called nitrogen fixation.

• Most nitrogen fixation is carried out by microorganisms such as Rhizobia. Rhizobium live in roots of leguminous plants such as peas and soybeans.

• Certain natural phenomena such as lightning, volcanic eruptions, forest fires and industrial processes such as combustion of fossil fuels also fix nitrogen.

★ $\textbf{\small{\underline{Nitrification :}}}$

• Ammonia which is fixed by bacteria or produced by decomposition of dead plants and animals is converted into nitrates or nitrites by certain type of bacteria.

• This process is called nitrification.

★ $\textbf{\small{\underline{Nitrogen Assimilation : }}}$

• The nitrates present in the soil are absorbed by the plant body.

• This process is called nitrogen uptake or assimilation.

• The nitrates are converted into usable organic nitrogen compounds within the plant body.

• Animals get nitrogen either by eating these plants or by eating other animals which eat plants.

★ $\textbf{\small{\underline{Ammonification :}}}$

• After plant or an animal dies, microorganisms and other soil organism act on its body.

• Their activity converts the organic nitrogen present in the body of dead plants and animals finally into ammonia and ammonium compounds.

• This process is called ammonification.

★ $\textbf{\small{\underline{Denitrification :}}}$

• Some of the nitrates present in the soil are absorbed by plants. The remaining nitrates are converted into nitrogen gas by denitrifying bacteria.

• This nitrogen gas is released into the atmosphere completing the nitrogen cycle.