State two ways by which nitrogen is fixed in nature. - Leaving Cert Chemistry - Question A - 2015

Lightning: Nitrogen in the atmosphere can be fixed during thunderstorms when high temperatures and pressures result in reactions that convert atmospheric nitrogen ( ext{N}_2) into nitrogen oxides. These oxides can subsequently be deposited into the soil through rain.

Nitrogen-Fixing Bacteria: Certain bacteria, such as Rhizobium, form symbiotic relationships with leguminous plants (e.g., alfalfa, clover, peas). These bacteria reside in the root nodules of these plants and convert atmospheric nitrogen into forms that can be utilized by the plants.