Nitrogen is vital for the physiological processes of plants. Nitrogen can be supplied to the plants in the form of nitrogen fertilizers. Though nitrogen is plenty in atmosphere, plants cannot use it and it should be converted into assimilable forms of nitrogen. This is done by the process of nitrogen cycle which includes the nitrogen fixation, ammonification, nitrification and denitrification.
The conversion of the atmospheric nitrogen into useful organic compounds by bacteria or the industrial process is called nitrogen fixation. These organic compounds are then converted into ammonia which can be assimilated by the plants through microbes by a process called ammonification. Ammonia is then converted to other assimilable form called the nitrates by nitrification mediated by bacteria. The nitrates formed is reduced back to nitrogen gas by a process called denitrification. This step of nitrogen cycle is not prefered by the farmers as it limits the availability of ammonia and nitrates to the plants.
