Effects of Exogenous Calcium Carbonate and Temperature on Active Organic Carbon Components and Microbial Mommunity Composition in Yellow Soil
In order to explore the effects of adding calcium carbonate on active organic carbon components and microbial community composition under different temperature conditions,the typical yellow soil in Guizhou province was taken as the research object,and six treatments were set up(the treatments with and without adding calcium carbonate at culture temperatures of 15,25,35℃)by isotope labeling method.By analyzing the effects of calcium carbonate addition on soil active organic carbon and microbial community composition at different temperatures,the distribution rule of foreign carbon in soil active carbon pool was revealed,with a view to providing a theoretical basis for organic carbon sequestration and improvement of typical yellow soil in Guizhou.The results showed that:The addition of calcium carbonate significantly increased the contents of DOC and MBC in soil at different temperatures(p<0.01),and the contents of DOC in soil treated with calcium carbonate reached the maximum value on the 5th day of culture.Compared with the treatment without calcium carbonate,the soil DOC content in the treatment with calcium carbonate were significantly increased by 83.41%,80.37%and 90.41%at 15,25 and 35℃,respectively.The temperature of calcium carbonate addition had significant effects on soil DOC and MBC(p<0.05).On the 15th and 60th day of culture,the contents of DOC and MBC in soil showed significant differences at different temperatures,and the overall content of DOC in soil was 35℃>15℃>25℃,and the overall content of MBC was 15℃>25℃>35℃.Isotopic labeling showed that the contents of 13 C-DOC and 13 C-MBC peaked at 15,25 and 35℃on the 1st and 5th day of culture,and the contribution rate of 13 C-DOC to the total soil DOC was 16.85%,21.20%and 15.22%,respectively.The contribution rate of 13 C-MBC to total soil MBC was 11.95%,10.49%and 17.18%,respectively.The addition of calcium carbonate significantly increased soil p H.High-throughput sequencing showed that the input of exogenous calcium carbonate had significant effects on the relative abundance and community structure of bacterial community composition,but had little effect on fungal community composition at day 60 of culture.The addition of calcium carbonate increased the relative abundance of Proteobacteria and decreased the relative abundance of Chlorocurvula.Correlation analysis showed that soil p H was positively correlated with the dominant bacteria Proteobacteria and Basidiomycota,and negatively correlated with Chloroflexi and Ascomycota.The chloromycetes was significantly negatively correlated with soil DOC,while the actinomycetes was significantly positively correlated with soil MBC,13 C-DOC and basidiomycetes was significantly positively correlated with DOC,13 C-MBC and 13 C-DOC.In conclusion,the effect of exogenous calcium carbonate on soil active organic carbon was greater than that of temperature.Exogenous calcium carbonate increased soil p H,soil DOC and MBC contents,and changed the composition and abundance of soil microbial community.Therefore,calcium carbonate addition is an effective measure for sequestration and improvement of organic carbon in yellow soil.
exogenous calcium carbonatetemperatureactive organic carbon componentmicrobial community composition