覆膜年限棉田土壤邻苯二甲酸酯含量分布及其对土壤细菌群落结构的影响--以准噶尔盆地荒漠-绿洲交错带为例

Distribution of PAEs content in film mulched cotton field and its effect on soil bacterial community structure:A case study at desert-oasis ecotone in the southern margin of Junggar Basin

为探究长期覆膜棉田土壤邻苯二甲酸酯(Phthalic Acid Esters,PAEs)含量及其对土壤微生物群落多样性的影响,以新疆准噶尔盆地南缘荒漠-绿洲交错带五家渠蔡家湖垦区0、5、10、15、20、25、30年覆膜年限棉田土壤为研究对象,分别采用GC-MS和Illumina-MiSeq高通量测序技术,对不同覆膜年限棉田土壤PAEs含量分布和土壤细菌群落组成及多样性进行分析。结果表明,长期覆膜棉田土壤中PAEs的分布随着覆膜年限的增加呈现先增长后降低的趋势。不同覆膜年限棉田土壤中微生物群落多样性存在明显差异,其中,覆膜棉田土壤中微生物多样性明显高于未覆膜对照样本,覆膜棉田土壤中15年地块最低。各覆膜年限棉田土壤中优势菌门均为放线菌门(Actinobacteriota)、变形菌门(Proteobacteria)。目水平上,微球菌目(Micrococcales)、假诺卡氏菌目(Pseudonocardiales)、土壤红杆菌目(Solirubrobacterales)是各样品中的优势目,其结构形成主要驱动因子是DnOP和土壤有机质。各覆膜样本中优势属为Gitt-GS-137、鞘氨醇单胞菌属(Sphingomonas)、KD4-96、Bacillus和Devosia,相对丰度之和分别占细菌总量的90.58%、91.06%、93.50%、91.24%、96.18%,有10个属的群落丰度与总PAEs或各单体存在明显相关,其中,剑菌属(Ensifer)、Pedosphaeraceae属、Devosia属与总PAEs或各单体存在着显著正相关性(P<0.05)。以上结果表明,各覆膜棉田土壤已受到PAEs污染,土壤PAEs污染对土壤微生物群落存在一定程度影响。

In order to investigate the content of PAEs in soil of cotton field with long-term film mulching and its effects on soil microbial community diversity,we sampled the soils of cotton fields with film mulching years of 0,5,10,15,20,25 and 30 years in Caijiahu reclamation area of Wujiaqu in the desert-oasis ecotone in the southern margin of Junggar Basin.Distribution of PAEs content and the composition and diversity of soil bacterial community were studied using GC-MS and Illumina Mesiq High-throughput sequencing technologies.Results show that the distribution of PAEs increases firstly and then decreases with the increase of film mulching years.There are significant differences in the diversity of microbial communities in cotton fields with different years of mulching,among which the diversities of bacterial communities in film mulching cotton soil are significantly higher than those controls without film mulching,and those in cotton soil with 15 years of film mulching are the lowest.The dominant phyla in cotton soil with different years of film mulching are Actinobacteria and Proteobacteria.At the order level,Micrococcales,Pseudonocardiales and Solirubrobacterales are the dominant orders,and the main driving factors are DnOP and SOM.The dominant genera in cotton soil samples with different years of film mulching are Gitt-GS-137,Sphingomonas,KD4-96,Bacillus and Devosia,the sum of relative abundance of above genera accounts for 90.58%,91.06%,93.50%,91.24%and 96.18%of the total bacteria,respectively.There are 10 genera that their community abundance in soil is significantly related to the total PAEs or individual monomers,among them the genus Ensifer,Pedosphaeracea and Devosia have a significant positive correlation with the total PAEs or individual monomers.The results show that the soil has been polluted by PAEs which has a certain impact on soil microbial community.