碳添加对土壤固碳细菌群落结构及多样性的影响——以松嫩平原盐碱耕地为例

采用高通量测序技术，研究秸秆、生物炭和纳米碳3种碳源添加对盐碱耕地土壤固碳细菌群落结构及多样性的影响，并分析土壤化学性质与固碳细菌群落多样性的关系.结果表明：3种碳源添加均降低土壤固碳细菌群落多样性，其中生物炭和纳米碳添加的土壤固碳细菌的Chao1指数、物种多样性、Shannon指数及系统多样性值均高于秸秆添加的.3种碳源添加均降低土壤固碳细菌群落的物种丰度，其中纳米碳添加的物种丰度大于秸秆和生物炭添加的.在群落组成方面及相对丰度上，3种碳源添加后的优势菌门为变形菌门（Proteobacteria），优势菌纲为γ-变形菌纲（Gammaproteobacteria），均在纳米碳添加后相对丰度最高，分别为90.38%、57.79%.群落组间差异分析结果显示，秸秆和纳米碳添加后土壤固碳细菌群落结构差异显著.冗余分析结果表明，土壤固碳细菌群落结构受土壤pH值、有机碳、全氮、全磷、碱解氮及有效磷的综合影响，其中土壤pH值和有效磷含量是影响土壤固碳细菌群落结构的主要化学性质.综合来看，在盐碱耕地中添加秸秆、生物炭或纳米碳，都抑制了土壤固碳细菌群落的多样性和物种丰度，但纳米碳能够增加土壤固碳细菌群落结构差异.

Effects of carbon addition on community structure diversity of CO2-assimilating bacterial in Saline-alkali cultivated land

The effects of straw(S), biochar(B) and nano-carbon(N) on the structure and diversity of CO₂-assimilating bacteria community in saline-alkali cultivated land were studied with the high-throughput sequencing technology, and the relationship between soil chemical properties and diversity of CO₂-assimilating bacteria community were also analyzed. These three carbon addition sources all reduced the diversity of CO₂-assimilating bacteria community. Chao1index, observed species, Shannon index and PD whole tree of CO₂-assimilating bacteria with B and N addition were higher than those with S addition. These three carbon additions also reduced the species abundance of soil CO₂-assimilating bacteria community. The species abundance of CO₂-assimilating bacteria community in N addition treated samples was higher than that with S and B addition treatments. In terms of community composition and relative abundance, the dominant phylum after these three carbon treatments was Proteobacteria, and the dominant phylum was Gammaproteobacteria. Their relative abundances in N treatment were the highest at 90.38%, and 57.70%, respectively. The results from differences group communities analysis showed that there were significant differences in the community structure of CO₂-assimilating bacteria after the addition of S and N. The results from redundancy analysis showed that the structure of CO₂-assimilating bacteria community was influenced by soil pH, organic carbon, total nitrogen, total phosphorus, available nitrogen and phosphorus. Soil pH and active phosphorus content were the main soil chemical properties affecting the structure of soil CO₂-assimilating bacteria community. Our findings suggested that the addition of S, B or N in saline-alkali cultivated land could inhibit the diversity and species abundance of soil CO₂-assimilating bacteria community, but the addition of N could increase the structure difference of soil CO₂-assimilating bacteria community.