The Nitrogen Cycle

Front 1

Nitrogen Fixation

Back 1

Nitrogen gas from the atmosphere is reduced by ammonia by Rhizobium. This ammonia can be used by leguminous plants as Rhizobium are found in their root nodules. They form a mutualistic relationship.

Front 2

Ammonification

Back 2

Where nitrogen compounds from dead organisms are turned into ammonium compounds by decomposers.

Animals waste also contains nitrogen compounds which are also turned in to ammonium by decomposers.

Front 3

Nitrification

Back 3

Ammonium compounds in the soil are changed into nitrogen compounds that can be used by plants.

First nitrifying bacteria (Nitrosomonas) change ammonium compounds into nitrites

Then other nitrifying bacteria called Nitrobacter changes nitrites into nitrates

Front 4

Denitifrication

Back 4

When nitrates in the soil are converted into nitrogen gas by denitrifying bacteria (they used nitrates in the soil to carry out respiration and produce nitrogen gas)

This happens under anaerobic conditions