Additives improved saprotrophic fungi for formation of humic acids in chicken manure and corn stover mix composting

The objective of this study was to analyze the effects of additives (biochar (BC) and palygorskite (PG)) on predominant fungi succession throughout composting of corn stover/chicken manure mix to influence humic substances formation (HS). Results indicated that BC and PG promoted the polymerization of HS and formation of more humic acids (HA), and BC performed better than PG, 10% additive was better than 5%. ITS rRNA gene sequencing showed that predominant fungi succession was significantly affected by BC and PG in composting, correlation between HS formation and predominant fungi indicated that BC and PG boosted lignocellulose-degrading fungi which could break down fulvic acids (FA) and HM to form more HA. Fungi function analysis showed that 10% BC significantly increased saprotrophic fungi, and decreased pathogenic fungi. Therefore, addition of 10% BC was conductive to promote the formation of HA and improve compost quality.