Nutrient transformations during composting of pig manure with bentonite

► Bentonite had no effects on the change of compost temperature and pH. ► Bentonite could facilitate OM degradation, increase TKN content and decrease the C/N ratio. ► Bentonite can reduce the extractable Cu and Zn content. ► The amount of Bentonite should be no more than 2.5% in composting.