What organisms can produce nitrogen?

Nitrogen is primarily produced by certain bacteria and archaea through a process called nitrogen fixation. These organisms, such as Rhizobium, Azotobacter, and cyanobacteria, convert atmospheric nitrogen (N₂) into ammonia (NH₃), which can then be utilized by plants. Additionally, some fungi and certain plants, like legumes, have symbiotic relationships with these nitrogen-fixing bacteria, further contributing to nitrogen availability in ecosystems.