Exploring the mechanisms through which basidiomycota fungi may influence slope stability

Current research at the university of Strathclyde is investigating the potential for basidiomycota fungi to be deployed as a nature-based technique to improve the stability of soil slopes. Basidiomycota are filamentous fungi which grow in the form of hyphae as they forage for nutrients in their surrounding environment. Hyphae are tubular structures with diameters between 2-7μm. Hyphae branch out and can anastomose forming a complex network, called the mycelium. Mycelial networks have attractive characteristics for use in ground engineering: evidence from natural analogues indicates that they can form massive, durable mycelia and they are resilient; dynamically responding to the environment and to damage/disruption.

A comprehensive experimental campaign has been conducted investigating the influence of the growth of basidiomycota fungi on soil behaviour including: assessment of liquid-solid contact angles, evaluation of water infiltration via instrumented columns, evaluation of saturated permeability and determination of soil water retention behaviour. Mechanical testing has included direct shear testing and jet-erosion testing. Our research shows that the growth of mycelial networks can influence the hydraulic and mechanical behaviour of soils via a number of different mechanisms including: (1) altering soil water repellency and infilling of pore space leading to reduced water infiltration and reduced permeability and (2) binding of soil particles via physical enmeshment within mycelial networks leading to enhanced soil cohesion and improved resistance to water-induced erosion. Furthermore, our results show that different fungal species can exhibit differences in growth behaviour and thus produce soil-mycelial systems with varying architecture which impacts upon the resulting soil behaviour. In summary, basidiomycetes show promise for enhancing slope stability by reducing water infiltration during heavy rainfall events, enhancing soil cohesion and improving soil resistance to erosion.