authors
Emilio Torres, Isabella Müller and Carlos García

abstract
The cultivation of edible mushrooms such as Pleurotus ostreatus (oyster mushroom) traditionally relies on substrate ingredients that can be cost‑intensive and resource-demanding. Biochar, a carbon‑rich byproduct of biomass pyrolysis, offers a promising low‑cost supplement once derived from spent mushroom substrate (SMS) or other agro‑wastes. This research investigates the economic feasibility of using biochar as a growth supplement in oyster mushroom production, analysing not only yield improvements but also input‑output ratios and cost savings relative to conventional substrate setups. Drawing on previous empirical findings, including improved moisture retention, nutrient stabilization, and yield increases of 13-25 % with biochar‑enriched substrates, our analysis shows that biochar supplementation can significantly enhance profitability for cultivators by reducing substrate waste and improving batch turnover rates. The economic model developed here demonstrates that, under realistic small‑ to medium‑scale production conditions, the cost per unit yield decreases while net margins rise, making biochar a viable alternative to traditional substrates. Given these results, biochar emerges as a scalable, sustainable, and economically sound supplement for oyster mushroom cultivation, with added environmental benefits of waste recycling and reduced reliance on virgin materials.