Legumes convert atmospheric nitrogen to usable ammonia nitrogen for the plant.
Inoculation is the process of introducing commercially prepared rhizobia bacteria into the soil. Each legume species requires a specific species of rhizobia to form nodules and fix nitrogen. Store inoculum and preinoculated seed in a cool environment without exposure to sunlight. Inoculum packages usually are labeled with an expiration date. This relationship occurs in specialized root tissue called nodules.