Fungal-treated soil

Fungi are ubiquitous in soil where their biomass can reach up to 75% of the total soil microbial biomass. Filamentous fungi grow by extending hyphae through soil pores, which also branches lateral hyphae along the hyphae length, creating an interconnected fibrous network known as mycelium. Fungal mycelium can cross-link and entangle soil particles, which reduces pore size and alters pore structures. Fungal mycelium can also secret hydrophobic compounds, increasing the water repellency of soils. This study investigated the effect of fungal mycelium on the hydraulic properties of sands. The results showed that fungal mycelia significantly increased matric suction, the magnitude of suction stress, and water repellency of sands. Hydraulic conductivities of fungal-treated sands reduced with increasing fungal growth periods. The reduced hydraulic conductivities of fungal-treated sands can be maintained even under the starvation condition. Scanning electron microscopy (SEM) images presented fungal mycelia significantly modified pore structures by cross-linking and entangling sand particles. Fungal mycelia can be potentially used for several geotechnical applications, including mitigation of soil surface erosion, seepage reduction, and enhancement of shallow slope stability.


SEM images of fungal-treated 50/70 and 20/30 sands showing fungal mycelium cross-linking and entangling sand particles. 50/70 sand: (a and b) cross-linking and (c and d) entangling. 20/30 sand: (e) cross-linking and (f) entangling.