dentrification
The conversion of ammonia and other nitrogen-containing nutrients into nitrogen gas is called denitrification. This process is carried out by denitrifying bacteria in the soil or aquatic environments and results in the release of nitrogen gas back into the atmosphere.
The process is called nitrogen fixation. Certain bacteria, like Rhizobium and Azotobacter, convert atmospheric nitrogen gas (N2) into ammonia (NH3) or nitrate (NO3-) that can be used by plants for growth. This conversion is essential in the nitrogen cycle as it makes nitrogen available for plant uptake.
nitrification= it is the conversion of ammonia first into nitrites then into nitrates by nitrifying bacteria. dentrification=it is the conversion of nitrites and nitrates into free nitrogen.