植被类型对煤矿区复垦土壤根际微生物的影响

Effect of Vegetation Type on Rhizosphere Microorganisms of Reclaimed Soils in Coal Mining Areas

煤矿开采改变了矿区土壤条件、地表植被覆盖和微生物生存环境。植被由于生长条件和根际分泌物的不同,影响根际土壤微生物的组成和多样性。以山西省晋华宫煤矿复垦区侧柏、云杉、樟子松、油松、桧柏5种复垦植被为研究对象,分析其土壤理化性质、根际土壤酶活性和微生物群落结构的差异性,并计算综合土壤肥力指数以反映不同复垦植被的生态恢复效果。结果表明:不同植被对土壤物理和化学性质、土壤酶活性、根际微生物多样性和群落结构具有显著影响,樟子松林具有最高的全碳、全氮含量,为微生物提供更多的碳氮等养分,导致其具有显著高的微生物丰度和多样性;不同植被类型间微生物群落差异性显著,变形菌门、酸杆菌门、放线菌门和拟杆菌门是优势菌门,全硫、容重和碱性蛋白酶是影响土壤根际微生物群落结构的关键因子;土壤综合肥力指数表明樟子松林和云杉林优于其他植被。综上,不同植被对矿区生态恢复的效果具有一定差异,樟子松林和云杉林有助于提高根际土壤细菌多样性和土壤肥力,研究可为半干旱区煤矿复垦区生态恢复的植被选择提供科学依据。

【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.