The first stable product of fixation of atmospheric nitrogen in leguminous plants is:

During the symbiotic nitrogen-fixation, bacteria present in the root nodules convert free atmospheric nitrogen (N2) to ammonia (NH3), which is utilized by the host plant for its development. The plants that contribute to nitrogen fixation are from the legume family. The root nodules of these plants contain symbiotic rhizobia bacteria that produce nitrogen compounds which help the plant growth.