Seed Inoculation

Seed inoculation involves applying live Rhizobium or Bradyrhizobium bacteria to legume seeds (soybeans, alfalfa, clover, peas) before planting. These bacteria colonize root nodules and convert atmospheric nitrogen (N₂) into plant-available ammonium, a process called biological nitrogen fixation. A well-inoculated soybean crop can fix 100–200 pounds of nitrogen per acre, significantly reducing fertilizer costs for the following crop in a rotation. Inoculants come in peat-based, liquid, and granular formulations and should be stored in cool, dark conditions to maintain bacterial viability. Inoculation is especially important when a legume is being planted in a field for the first time or after several years without that crop, because compatible rhizobia may not be present in sufficient numbers in the soil.