Nitrogen Fixation
/NY-troh-jen fik-SAY-shun/🦋 Ecology●● Intermediate
Nitrogen fixation is the biological process by which certain bacteria (free-living or symbiotic) convert atmospheric nitrogen gas (N₂) into ammonia (NH₃), which plants can absorb. The most important fixers are Rhizobium bacteria in root nodules of legumes. Nitrogen-fixing plants like clover, alders, and lupins enrich soil fertility naturally and are valuable in companion planting and ecological restoration.
Etymology
From Latin nitro (niter, saltpeter) + Greek genesis (origin) + Latin fixus (fastened)
Example
“Alder trees fix nitrogen through symbiotic bacteria in their root nodules, enriching the surrounding soil.”