Fungal hyphae and structural stability of soil

This review describes the possible mechanisms by which fungal hyphae, especially those of vesicular-arbuscular mycorrhizal (VA) fungi, bind microaggregates of soil (<0.25 mm diameter) into stable macroaggregates (>0.25 mm), and suggests a model of the formation of a stable macroaggregate by fungal hyphae. Factors which affect the growth of VA mycorrhizal hyphae in soil and their production of extracellular polysaccharides are discussed in relation to stable macroaggregates. The interactions between clay particles and hyphae are described. The review suggests areas of future research on stabilization of aggregates by VA mycorrhizal hyphae.