Windrow composting mitigated CH 4 emissions: characterization of methanogenic and methanotrophic communities in manure management

With increasing livestock breeding, methane ( CH 4 ) emissions from manure management will increasingly contribute more to atmospheric CH 4 concentration. The dynamics of methanogens and methanotrophs have not yet been studied in the manure environment. The current study combines surface CH 4 emissions with methanogenic and methanotrophic community analyses from two management practices, windrow composting ( WCOM ) and solid storage ( SSTO ). Our results showed that there was an c . 50% reduction of CH 4 emissions with WCOM compared with SSTO over a 50‐day period. A sharp decrease in the quantities of both methanogens and methanotrophs in WCOM suggested that CH 4 mitigation was mainly due to decreased CH 4 production rather than increased CH 4 oxidation. Pyrosequencing analysis demonstrated that aeration caused a clear shift of dominant methanogens in the manure, with specifically a significant decrease in Methanosarcina and increase in Methanobrevibacter . The composition of methanogenic community was influenced by manure management and regulated CH 4 production. A sharp increase in the quantity of methanotrophs in SSTO suggested that microbial CH 4 oxidation is an important sink for the CH 4 produced. The increased abundance of Methylococcaceae in SSTO suggested that Type I methanotrophs have an advantage in CH 4 oxidation in occupying niches under low CH 4 and high O 2 conditions.