科尔沁沙地草甸草地开垦农田对土壤细菌群落结构的影响 Effect of Conversion from Natural Meadow Grassland to Farmland on the Structure of Soil Bacterial Community in Horqin Sandy Land

选择天然草甸草地及开垦农田后7年和50年样地，采用IlluminaMiSeq高通量测序的方法研究了草甸草地利用方式改变后，土壤细菌群落结构的变化特征及与土壤理化性质的关系。结果表明，天然草地开垦农田对土壤理化性质有显著影响，有机质和全N含量迅速下降，电导率提高。Proteobacteria，Acidobacteria，Actinobacteria，Bacteroidetes，Chloroflexi，Gemmatimonadetes，Firmicutes，Planctomycetes，Verrucomicrobia，Thaumarchaeota和Nitrospirae是本地区的优势菌群。草地利用方式改变对土壤细菌群落结构有显著影响，引起优势菌群相对优势度改变，但对物种组成没有显著影响。土壤理化性质对细菌群落结构的形成有重要作用。 To investigate how soil bacterial communities respond to the change during conversion from natural meadow grassland to farmland, and the relationship between bacterial community and soil properties, we detected the shifts in diversities and compositions of soil bacterial communities as well as the relative abundance of dominant bacterial taxa with the high throughput IlluminaMiSeq sequencing technique from natural grassland, 7-yr farmland, and 50-yr farmland in Horqin Sandy Land. We found that land-use change resulted in the significant changes in soil physical and chemical properties with the distinct decreases in soil organic matter and total N contents and the increase in soil conductivity. Soil bacterial community structure was affected by land-use change, with the significant change in relative abundance of dominant bacterial populations. However, species composition of bacterial community remained unchanged. Soil properties had important effects on the structure of soil bacterial community. Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Firmicutes, Planctomycetes, Verrucomicrobia, Thau- marchaeota, and Nitrospirae were the dominant taxa in the Horqin area.