In this study we evaluated CO2
emissions during composting of green wastes with clay and/or biochar in the presence and absence of worms, as well as the effect of those amendments on carbon mineralization after application to soil. Our results indicated that the addition of clay or clay–biochar mixture reduced carbon mineralization during co-composting without worms by up to 44 %. In the presence of worms, CO2
emissions during composting increased for all treatments except for the low clay dose.