title: Responses of soil methanogens, methanotrophs, and methane fluxes to land-use conversion and fertilization in a hilly red soil region of southern China.
abstract: Changes in land-uses and fertilization are important factors regulating methane (CH4) emissions from paddy soils. However, the responses of soil CH4emissions to these factors and the underlying mechanisms remain unclear. The objective of this study was to explore the effects of land-use conversion from paddies to orchards and fertilization on soil CH4fluxes, and the abundance and community compositions of methanogens and methanotrophs. Soil CH4fluxes were quantified by static chamber and gas chromatography technology. Abundance and community structures of methanogens and methanotrophs (based on mcrA and pmoA genes, respectively) were determined by quantitative real-time PCR (qPCR), and terminal restriction fragment length polymorphism (TRFLP), cloning and sequence analysis, respectively. Results showed that land-use conversion from paddies to orchards dramatically decreased soil CH4fluxes, whereas fertilization did not distinctly affect soil CH4fluxes. Furthermore, abundance of methanogens and methanotrophs were decreased after converting paddies to orchards. Fertilization decreased the abundance of these microorganisms, but the values were not statistically significant. Moreover, land-use conversion had fatal effects on some members of the methanogenic archaea (Methanoregula and Methanosaeta), increased type II methanotrophs (Methylocystis and Methylosinus), and decreased type I methanotrophs (Methylobacter and Methylococcus). However, fertilization could only significantly affect type I methanotrophs in the orchard plots. In addition, CH4fluxes from paddy soils were positively correlated with soil dissolved organic carbon contents and methanogens abundance, whereas CH4fluxes in orchard plots were negatively related to methanotroph abundance. Therefore, our results suggested that land-use conversion from paddies to orchards could change the abundance and community compositions of methanogens and methanotrophs, and ultimately alter the soil CH4fluxes. Overall, our study shed insight on the underlying mechanisms of how land-use conversion from paddies to orchards decreased CH4emissions.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Science, Beijing, 100049, China.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. xingwu@rcees.ac.cn.|Joint Center for Global Change Studies, Beijing, 100875, China. xingwu@rcees.ac.cn.
authors.forename: Xing
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|Joint Center for Global Change Studies, Beijing, 100875, China.
authors.forename: Zongshan
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Science, Beijing, 100049, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Science, Beijing, 100049, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. ghliu@rcees.ac.cn.|Joint Center for Global Change Studies, Beijing, 100875, China. ghliu@rcees.ac.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Liu
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D002681:China; D005308:Fertilizers; D005798:Genes, Bacterial; D008697:Methane / Q000032:analysis*; D008772:Methylococcaceae / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D012275:Oryza / Q000254:growth & development; D012150:Polymorphism, Restriction Fragment Length; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D005308:Fertilizers; D012987:Soil; D008697:Methane
keywords: CH4 fluxes; Fertilization; Land-use conversion; Methanogens; Methanotrophs