Experimental investigation of the influence of the growth of saprotrophic fungi (Pleurotus ostreatus) on the aggregate stability of a silty sand

Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK

^* Corresponding author: Grainne El Mountassir: grainne.elmountassir@strath.ac.uk

Abstract

Granular soils are highly susceptible to erosion, a process that may contribute to slope instability. For example, gully erosion promotes preferential flow and toe erosion, eventually leading to undercutting and slope failure. Given that soil erodibility is correlated with soil aggregate stability, here we use the slaking test as an indicator of the loss of soil structure and ultimately erodibility upon wetting. The overall aim of this research is to experimentally study the influence of the growth of saprotrophic fungus Pleurotus ostreatus ( P. ostreatus), on the aggregate stability of a silty sand. Two main factors were investigated in this study: (i) the amount of fungal biomass inoculant and (ii) the concentration of nutrients (malt extract broth) supplied to the soil. The results demonstrate that P. ostreatus growth can enhance the aggregate stability of silty sand. Based on visual observations, the slaking index and UV microscopy, these preliminary results indicate that aggregate stability is positively related to the amount of fungal hyphae in the soil, which is influenced both by the initial amount of fungal biomass added into the soil and the nutrient concentration supplied.