Effect of Vegetation Type on Rhizosphere Microorganisms of Reclaimed Soils in Coal Mining Areas
[Objective]Long-term mining activities have caused serious damage to the ecological environment in the mining area.Soils near mining areas have reduced quality,decreased vegetation cover,and changed microbial habitats.Stripped soil and coal gangue are mixed to form hillocks and the exposed surface of the hillocks is highly susceptible to wind and water erosion,which has resulted in increasingly severe damage to the ecosystems,including changes in plant species composition and community structure,reduced biodiversity and productivity,deterioration of soil and microenvironment,and changes in the relationships between organisms.Hence,the ecological restoration of the coal mines is an urgent task.Interestingly,vegetation types may affect the composition and diversity of microbial communities in rhizosphere soil owing to the growth conditions,vegetation cover,root turnover rates,and the chemical composition of root exudates.Therefore,it is important to explore the response of microbial community composition and diversity under different vegetation types in mining ecological restoration areas.[Method]The rhizosphere soils of five vegetation types(Platycladus orientalis,Picea asperata,Pinus sylvestris,Pinus tabuliformis,and Sabina chinensis)were collected in this study to detect the soil physicochemical properties,enzyme activities,and bacterial community structure.Also,we identified key environmental factors affecting rhizosphere bacterial communities using redundancy analysis and conducted a mantel-test analysis between dominant bacterial phyla and environmental factors.Structural equation models were established to explore the interactions between plants,soil,and microbes.Furthermore,the soil-integrated fertility index was calculated to analyze the ecological restoration effectiveness of different vegetation types.[Result]Vegetation types had significant effects on soil physicochemical properties,enzyme activities,bacterial community composition,and diversity.The P.sylvestris field had significantly higher total carbon content,total nitrogen contents,bacterial abundance,and diversity,while soil alkaline phosphatase and soil urease activities were significantly higher in the P.asperata field.The Proteobacteria,Acidobacteria,Actinobacteria,and Bacteroidetes were the dominant phyla of soil bacterial communities.Also,the dominant genera were RB41,Streptomyces,MND1,Ferruginibacter,and Variovorax.Total sulfur,soil bulk density,and soil alkaline protease were the key factors affecting the structure of rhizosphere soil bacterial communities.Our analysis revealed that vegetation types can directly affect soil physicochemical properties,soil enzyme activities,and bacterial community structure,as well as indirectly affect rhizosphere soil bacterial community structure through soil physicochemical properties and soil enzyme activities.Soil integrated fertility index indicated that P.sylvestris and P.asperata were superior to other vegetation in the ecological restoration of mining areas.[Conclusion]Vegetation types have significant effects on soil physicochemical properties,soil enzyme activity,and bacterial community in the rhizosphere.P.sylvestris and P.asperata can improve the rhizosphere soil bacterial diversity and soil fertility,which is beneficial to the ecological restoration of the coal mine reclamation area.This study provides a scientific basis for vegetation selection for ecological restoration of coal mine reclamation areas in semiarid regions.
Mining reclamationVegetation restoration typesSoil enzyme activityRhizosphere microbial community
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