Nitrogen is an essential element for the growth of plants and microorganisms. However, plants can’t fix atmospheric nitrogen and thus rely on other organisms to convert it into a form they can use. There are several groups of microorganisms that can fix atmospheric nitrogen in the soil and make it available to plants. These include:
- Nitrogen-fixing bacteria: Bacteria such as Rhizobia and Frankia can fix nitrogen from the air and convert it into ammonia (NH3) or nitrite (NO2) that can be used by plants. These bacteria form symbiotic relationships with certain plants, such as legumes, and live in nodules on their roots.
- Cyanobacteria: Cyanobacteria, also known as blue-green algae, can fix atmospheric nitrogen through a process called nitrogen fixation. They can live in aquatic environments as well as in soil or on plants.
- Azotobacter: Azotobacter are free-living nitrogen-fixing bacteria found in soil, and they can fix atmospheric nitrogen in the absence of a host plant.
Overall, the nitrogen fixation process is carried out by a diverse group of microorganisms including bacteria, cyanobacteria and a few fungi. These microorganisms play a vital role in the nitrogen cycle by converting atmospheric nitrogen into forms that plants can use, making it a critical process for the growth of plants and maintaining soil fertility.