[[1]] fixation is the process that converts atmospheric nitrogen to nitrogenous compounds that can be absorbed by plants.

Nitrogen fixation is the biological process by which certain types of microorganisms, such as blue-green algae and Rhizobium bacteria, convert atmospheric nitrogen into forms of nitrogen that can be used by plants. This process is essential for plant growth and development because nitrogen is a key component of amino acids, nucleic acids, and other important cellular molecules. Nitrogen fixation also plays an important role in improving soil fertility by adding nitrogen to the soil, which can increase crop yields and support a healthy ecosystem.