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Effect of different particle-size biochar on methane emissions during pig manure/wheat straw aerobic composting: Insights into pore characterization and microbial mechanisms

He, Xueqin, Yin, Hongjie, Sun, Xiaoxi, Han, Lujia, Huang, Guangqun
Bioresource technology 2018 v.268 pp. 633-637
Archaea, additives, bacteria, biochar, composting, greenhouse gas emissions, methane, methane production, methanogens, methanotrophs, micro-computed tomography, particle size, pig manure, porosity, rice straw, wheat straw
This study explored the effects of different particle sizes of rice straw biochar (RSB) on the methane emissions of pig manure/wheat straw aerobic composting experiments to provide a theoretical suggestion for biochar application. The experiments were conducted with a control group, powder (<1 mm) group, and granular (4 mm–1 cm) group. Methane emissions increased by 56.84% in the powder group but decreased by 22.15% in the granular group during the aerobic composting. Methane was generated by methanogens and methanotrophs in the specific anaerobic micro-environment characterized by X-ray micro-computed tomography (micro-CT). The porosity of initial composting samples increased by 4.02% in the granular group but decreased by 3.88% in the powder group. RSB additives typically reduced the mcrA/pmoA ratio and increased the diversity of Bacteria and Archaea. Conclusively, granular biochar benefits to aerobic composting to alleviate the CH4 emissions.