Rhizobium

Rhizobium is a genus of soil bacteria that is of great significance to agriculture. In symbiotic relationships with certain plants, Rhizobium helps those plants to gain access to nitrogen, an essential nutrient for growth. The bacteria form nitrogen-fixing nodules on the plant roots, where they convert nitrogen from the atmosphere into a form usable by the plant. Without this process, known as nitrogen fixation, many important crops would not be able to grow. Rhizobium is also a popular soil amendment, adding nitrogen-rich bacteria to soils to improve crop yields.