炉渣与生物炭施加对稻田土壤产甲烷菌群落结构的影响

为了了解废弃物施加处理影响稻田甲烷排放通量的微生物学机制,对稻田分别进行炉渣、生物炭单一施加和混合施加处理,分析施加处理条件下早、晚稻拔节期稻田土壤的理化性质,并采用PCR-RFLP技术及克隆测序对稻田土壤中的产甲烷菌群落组成多样性及其结构进行分析。研究结果表明:早稻拔节期,混施处理显著提高土壤盐度和pH;晚稻拔节期,混施处理显著提高土壤盐度,炉渣和混施处理显著提高pH。香农-威纳指数(H')和辛普森指数(D)显示:炉渣、生物炭和混施处理提高了稻田土壤产甲烷菌的多样性。群落组成分析结果表明:稻田土壤产甲烷菌主要含有甲烷微菌目(Methanomicrobiales)、甲烷杆菌目(Methanobacteriales)、甲烷八叠球菌目(Methanosarcinales)、甲烷球菌目(Methanococcales)、甲烷胞菌目(Methanocellales)和Methanomassiliicoccales等6大类群,其中甲烷微菌目(Methanomicrobiales)为优势类群。从属水平的群落结构来看,与对照相比,3种施加处理均降低了早稻土壤Methanomassiliicoccus相对丰度;生物炭处理还降低了Methanosarcina相对丰度。初步认为Methanomassiliicoccus和Methanosarcina这2个菌属与CH_4排放量减少密切相关。

Effects of slag and biochar amendments on methanogenic community structures in paddy fields

To understand the effects of waste amendments on microbiological mechanisms of methane emissions in paddy fields, the effects of single and mixed slag and biochar amendments on soil physicochemical properties were investigated in the elongation stage of both early and late paddy fields. Moreover, the diversity of methanogens and their community structures under different waste amendments were also investigated using PCR-RFLP and sequencing. The results showed that during the elongation stage of early paddy fields, both soil salinity and pH were significantly increased in mixed amendments. During the elongation stage of late paddy fields, soil salinity was significantly increased in mixed amendments, while soil pH was significantly increased in slag and mixed amendments. Shannon index (H'') and Simpson diversity index (D) showed that the diversity of methanogens in soil treated with slag, biochar, and mixed amendments was higher than that of the control. Phylogenetic analysis showed that methanogeni communities in the paddy fields could be subdivided into six groups:Methanobacteriales, Methanomicrobiales, Methanosarcinales, Methanococcales, Methanocellales, and Methanomassiliicoccales. The most dominant methanogenic group was Methanomicrobiales. Comparison with the control, the relative abundance of Methanomassiliicoccus was lowered in the three types of treatments of the early paddy fields, and the relative abundance of Methanosarcina was lowered in biochar amendment. The relative abundance of Methanomassiliicoccus and Methanosarcina may have contributed to decreased CH₄ emissions.