Question 6
Name the microorganisms which can fix atmospheric nitrogen in the soil.

Bacteria such as Rhizobium and certain blue-green algae can fix atmospheric nitrogen in the soil.The process of conversion of atmospheric nitrogen into nitrogen compounds by certain bacteria such as Rhizobium which is present in the root nodules of legumes like peas, beans etc. is known as nitrogen fixing or nitrogen fixation.This process helps in enhancing the fertility of the soil.Blue-green algae (Cyanobacteria) are widespread in marine, freshwater and terrestrial environments and are also capable of fixing atmospheric nitrogen.