Vermiculite changed greenhouse gases emission and microbial community succession in vermicomposting: Particle size investigation

Greenhouse gas emissions during composting inevitably cause environmental pollution. This study investigated the effects of 10 % vermiculite of four particle sizes (<1.5 mm, 1.5–3 mm, 3–5.5 mm and 5.5–8 mm) on greenhouse gas emissions during vermicomposting of corn stover and cow dung. The results revealed that vermiculite reduced CH₄ and N₂O emissions but increased CO₂ emissions. Vermiculite with a particle size of 3–5.5 mm presented the greatest environmental benefits, increasing cumulative CO₂ emissions by 19 % and reducing CH₄ and N₂O emissions by 49 % and 62 %, respectively. A negative correlation was found between the specific surface area of vermiculite and cumulative greenhouse gas emissions (r = −0.7949). Furthermore, vermiculite intensified microbial interactions and accelerated microbial community succession. These results have important implications for understanding how vermiculite regulates greenhouse gas emissions and microbial mechanisms during the vermicomposting process.