Definition - What does Nitrogen-Fixing Bacteria mean?
Nitrogen-fixing bacteria are microscopic organisms that are able to convert atmospheric nitrogen into compounds that occur in soil and that are used by plants as nutrients. Certain species of these bacteria are free-living while other species exist in symbiotic relationships with plants where they populate root hairs and benefit their host plants through their nitrogen-fixing activities.
Safeopedia explains Nitrogen-Fixing Bacteria
Nitrogen forms the basis of the proteins that make plant, animal and human life possible. However, atmospheric nitrogen is not present in a form that is available to plants and, ultimately, humans and animals. Nitrogen is also readily depleted from the soil. The primary means of natural nitrogen fixation is through the activity of nitrogen-fixing bacteria. Plants having symbiotic or mutualistic relationships with nitrogen fixers are mainly from the legume family.