The Effect of Biochar and Bacterium Agent on Humification During Swine Manure Composting

The aim of this study was to evaluate the evolutions of humic substance (HS) during the process of swine manure composting with biochar and a bacterium agent. HS was studied by quantification of the extractable humic substance including extractable carbon (EXC), humic acid carbon (HAC), and fulvic acid carbon (FAC). Three composting treatments (none, bacterium agent, and bacterium agent + biochar) were conducted by the turned-pile system. The result showed that the organic matter of the swine manure–biochar mixture treatment was characterized by a high polymerization degree of the humic-like substances, with a relatively high proportion of humic acids to fulvic acids. The composting with bacterium agent performed higher EXC and HAC content than that without bacterium agent. Biochar also significantly increases the content of HAC during swine manure composting, while there were no significant differences of EXC content than bacterium agent treatment.