PubMed · 2026-05-30
Composting spent mushroom substrate (the leftover material after mushroom cultivation) before using it as a selenium-enriched fertilizer locks selenium more safely into soil, while simply stacking it makes selenium more mobile and potentially leachable. The difference comes down to how composting transforms the organic matter and shapes the soil microbial community.
Composted selenium-enriched substrate reduced soil selenium mobility by 12–13%, while stacked (uncomposted) substrate increased it by 17–18%.
Composting increased the humic acid-bound selenium fraction by 30–40%, locking selenium into stable organic forms that resist leaching.
Composted fertilizer shifted soil bacterial communities toward active metabolic functions and strengthened microbe-organic matter interactions, while stacked fertilizer triggered stress responses in soil bacteria.
