Distribution characteristics of bacteria in soil aggregates of greenhouse soil
[Objective]The alteration of soil structure can lead to changes in the composition of soil bacterial communities.How-ever,the impact of different particle sizes on bacterial community structures within soil aggregates under greenhouse soil re-mains unclear.[Methods]In this paper,the typical soil type of North China Plain under long-term greenhouse environment-tidal soil is taken as the research object,the stability of aggregates and the abundance and community composition of bacteria in aggregates of different particle sizes were studied by using qPCR and high-throughput sequencing techniques.[Results]The proportion of aggregates＞2 mm in the greenhouse soil was significantly higher compared to that in the open soil.The mean weight diameter and geometric mean diameter of the greenhouse soil aggregates were 44.5％and 65.0％higher,respectively,than those in the open soil,while the fractal dimension was significantly lower.Through amplification and sequencing of bacte-rial 16S rRNA sequences,we obtained a total of 11 513 OTUs in the greenhouse soil and 11 037 OTUs in the open soil.Among these,the number of unique OTUs was highest among＜0.25 mm aggregates.There was no significant difference observed in the abundance of bacterial 16S rRNA genes among different levels of aggregates within the greenhouse soil;however,there was a significant difference between aggregate sizes within open soil with a ratio difference of 5.21 times between aggregates sized from 2-0.5mm and those sized from 0.5-0.25 mm.Furthermore,there were significantly more bacterial species present in the greenhouse soil compared to that found in open soil.Principal component analysis revealed distinct differences between bac-terial community structures within both greenhouse soils and＜0.5 mm aggregates when compared to those found within open soils or other aggregate sizes.The dominant bacteria phyla identified across both greenhouse soils and open soils included Pro-teobacteria,Acidobacteria,Bacteroidetes,and Actinobacteria;whereas RB41,MND1,and Sphingomonas were identified as dominant bacteria genera.Significant differences at both phylum level and genus level were observed between bacteria present within treated soils'aggregates.[Conclusion]The greenhouse environment promotes the formation of large aggregates in soil,enhancing the stability and uniformity of aggregates.Redundancy analysis results revealed that soil pH played a pivotal role in shaping bacterial community structure within both greenhouse and open soil,while soluble organic carbon content exerted sig-nificant influence on bacterial community structure across all aggregate levels.
NETL
NSTL
万方数据
