All life requires nitrogen as it is an essential element in the universal molecules proteins and nucleic acids. The nitrogen concentration in the atmosphere is almost 78%, which means that it is the major global reservoir of nitrogen. In the soil, nitrogen is present as both organic (amino acids, amino sugar and nucleic acids), and inorganic components (NH4+, NH2OH, N2, N2O, NO, NO2- and NO3-). Soil microorganisms play an important role in the nitrogen cycle as they mediate the movement of nitrogen between the atmosphere, biosphere and geosphere. By bacterial fixation, atmospheric nitrogen is made available to the soil ecosystem and thereby to plants and other organisms.