Spread of mycorrhizal fungi through soil

Abstract The spread of mycorrhizal fungi through soil was estimated by transplanting clover plants infected with morphologically distinct mycorrhizal fungi into troughs of soil. Mycorrhizal fungi spread into non‐mycorrhizal seedlings at rates of 0.6–1.5 m/year and into mycorrhizal seedlings at rates of 0.9–3.2 m/year. Mycorrhizal infestation of the trough soil greatly reduced the spreading rate of an introduced fungus. A precrop of kale or mustard grown in the trough soil repressed the soil's mycorrhizal infectivity and allowed an introduced fungus to spread rapidly.