Determination of dynamic physical properties of peat and bark-based alternative casing materials for mushroom cultivation using X-ray computed tomography

Current mushroom (Agaricus bisporus) cultivation practices use peat, an environmentally costly resource. Peat functions as a water reservoir, supporting mycelial growth and mushroom formation. There is a knowledge gap in characterizing the physical attributes of alternative materials; conventional methods are destructive and often imprecise. This research aimed to determine, over time, the physical properties of peat and two bark-based alternative casing materials using X-ray computed tomography as a novel, high-resolution approach. A microcosm culturing technique was developed to facilitate scanning. A series of scans was taken at key growth stages to assess the dynamic changes that occur within the casing over the course of a mushroom production cycle. Measurements of porosity, pore surface area and pore size distribution revealed significant differences between peat and bark-based alternatives in addition to capturing the changes within each casing material over the mushroom production life cycle. Peat was found to have greater average pore size than bark-based treatments, and this divergence in pore size distribution increased significantly between treatments over the time frame of the experiment. A significant finding of the research is that relative increases in the air-filled porosity of different casing materials may be a useful predictor of casing media performance.