Inoculation means introducing pathogens, antigens, or microorganisms to living organisms or growth mediums (such as soil) to create immunity against disease.

In agriculture, inoculation is about introducing beneficial microorganisms like mycorrhizal fungi or Rhizobium bacteria to soil, plant roots, or seeds. This has numerous potential benefits such as nutrient uptake, drought and pathogen resistance, which lead to healthier plants / crops and increased yields. Microbial inoculants function as biofertilizers which can fix nitrogen and help with phosphorus uptake, and reduce dependence on synthetic chemical fertilizers.

Please see the definition of mycorrhizal inoculation.