This NebGuide discusses when soybean seed should be inoculated and why, and provides recommendations on inoculant types to use. Special Considerations Recommendations Soybeans can obtain up to half of their nitrogen needs from the air when nitrogen-fixing rhizobia bacteria are present in the soil. Reinoculation may be necessary in fields with a past history of soybeans.
Nodules are very apparent on carefully dug soybeans.
Nodule rhizobia convert atmospheric nitrogen to forms that can be used by the plant. The relationship between rhizobia and plants is unique to legumes. When infected by rhizobia, the plants form special structures called nodules that enclose the rhizobia colonies. The rhizobia species that inoculates soybeans is not native to Nebraska soils and nodulates only soybeans. It is different from those that fix nitrogen in alfalfa and other legumes.