The application of rapidly composted manure decreases paddy CH4 emission by adversely influencing methanogenic archaeal community: a greenhouse study

Purpose The application of organic manure can alleviate the deterioration of soil quality. However, it inevitably increases paddy CH4 emissions by introducing more CH4-producing precursors, which further restricts the amendment of organic manure in paddy fields. A 17-week greenhouse pot experiment was conducted to compare the effects of noncomposted manure (NCM), commonly composted manure (CCM), and rapidly composted manure (RCM) on rice yield and CH4 emission. To understand CH4 emissions of these three different manures, both the population size and the community structure of the methanogenic archaea in the soils were also investigated. Materials and methods The experiment was carried out in a greenhouse with three treatments: NCM, CCM, and RCM. The CH4 fluxes during rice cultivation were measured using the closed static chamber technique, and the CH4 concentration was determined by FID gas chromatography (Agilent 7890, USA). Soil DNAwas extracted from 0.5 g of moist soil using a FastDNA (R) SPIN Kit for soil (MP Biomedicals, Santa Ana, CA) according to the manufacturer's instructions. The population size of methanotrophs and methanogenic archaea was determined by real-time quantitative PCR (qPCR), and the community composition was analyzed using pyrosequencing technology. Results and discussion Rice yield and CH4 emission significantly differed between the groups (P < 0.05) as follows: CCM