How does manganese dioxide affect humus formation during bio-composting of chicken manure and corn straw?

Abstract The aim of this study is to reveal the roles of MnO 2 in Maillard reaction of biotic composting, and to identify its effectiveness in promoting humus formation. Corn straw (CS) and chicken manure (CM) have been chosen to be composted. During CS composting, addition of MnO 2 rapidly reduced reducing sugars concentration (decreased by 84.0%) in 5 days and significantly improved humus production by 38.7% compared with treatment without MnO 2 . Whereas in CM composting, the promoting effect of MnO 2 on humus formation was relatively weak by comparing with the treatment group of CS. Additionally, the presence of MnO 2 has reshaped bacteria community, which might be the reason of MnO 2 stimulated bacteria to utilize organic matter during CM composting. Therefore, the structural equation modeling has confirmed that MnO 2 mainly performed as chemical catalyst to promote humus formation during CS composting. Besides catalyst, MnO 2 also played as a bioactive activator in CM composting.