The role of mycorrhizal fungi in soil structure. . Mycorrhizal fungi are key players in soil structure. Soil structure is tremendously important in the health of the vegetation, because it facilitates water infiltration, aeration, root growth, and movement of soil animals.
Structure refers to the arrangement of soil particles into aggregates.
The aggregates stick together into larger aggregates, leading to a complex hierarchy of size classes, with soil voids between the aggregates. Soils without pore space are very unfriendly to plant growth. Both ECM and VAM fungi facilitate soil structure by binding soil aggregates together, to each other, and to plant roots. Soil bacteria cement soil particles and contribute importantly to soil structure, and mycorrhizal hyphae help supply some of the fuel that keeps the soil bacteria alive. Additional forces in soil structure are burrowing animals, including earthworms, and certain chemical forces that act primarily on the smallest aggregates sizes.