Rhizosphere Soil Microecological Environment Characteristics And Soil Quality Evaluation Of Different Ecological Restoration Vegetation In The Arsenic Sandstone Area

By analyzing the characteristics and soil quality index of different rhizosphere soil microecological environment of different ecological restoration vegetation in the arsenic sandstone area,the effect of ecological restoration was evaluated,and the succession rule of rhizosphere soil microecological environment was clarified,that will provide theoretical basis for scientific evaluation of ecological effects of ecological restoration vegetation in the regulation of microecological environment in the arsenic sandstone area.In this study,the changes of soil microbial community structure,soil microbial biomass,soil enzyme activities related to soil nutrient conversion,soil nutrient content and ecological stoichiometric characteristics were analyzed in four planting coverages.The planting coverages included Pinus tabulaeformis plantation,Caragana Korshana plantation,natural restored grassland and abandoned land,respectively.And the soil quality index method was used to establish a comprehensive soil quality evaluation system.The soil quality in different ecological restoration vegetation was comprehensively evaluated,the influence of different ecological restoration vegetation on the characteristics of rhizosphere soil microecological environment were analyzed,the leading factors affecting the stability of soil microecological environment were explored,and the suitable ecological restoration tree species were selected.The results show that:(1)The relative abundance of fungi was the highest in P.tabulaeformis plantation(15.27%).The relative abundance of soil Gram-negative bacteria was the highest in natural restored grassland(34.28%).The ratio of fungi to bacteria was the highest in P.tabulaeformis forest.The ratio of gram-positive and Gram-negative bacteria was lower in naturally restored grassland than that in the other planting coverages.(2)The enzyme activities related to nutrient conversion in rhizosphere soil and the contents of carbon,nitrogen and phosphorus(MBC,MBN and MBP)in soil microbial biomass of P.tabulaeformis plantation were significantly higher than those in other vegetation types.The soil soluble organic carbon(DOC)content was the highest in P.tabulaeformis plantation,and the total carbon content was significantly increased in the other three ecological restoration vegetation.(3)The naturally restored grassland had a higher microbial biomass in the stoichiometric characteristics of 4 kind vegetation types,but the microbial biomass was the lowest in abandoned land.The result of enzyme stoichiometric characteristics indicted that the relative carbon restriction of microorganisms was the highest in C.Korshinskii plantation.The MBC:MBP was significantly higher in P.tabulaeformis plantation,C.Korshinskii plantation and restored grassland than that in abandoned land,and the soil available phosphorus was relatively deficient.(4)The arbuscular mycorrhizal fungi significantly affected the stoichiometric characteristics of soil microbial biomass,and the actinomyces had the strongest effect on soil enzyme stoichiometric characteristics.The arbuscular mycorrhizal fungi and actinomyces synergistically could regulated rhizosphere soil nutrient elements.Soil total phosphorus content significantly affected the MBC:MBN and MBC:MBP,and that affected the rhizosphere soil microbial community structure.Soil available nitrogen content plays a significant role in regulating enzyme stoichiometry in microecological environment.(5)The order of soil quality comprehensive score was P.tabulaeformis plantation >natural restored grassland > C.Korshinskii plantation > abandoned land.The soil quality evaluation score was the highest in P.Tabulaeformis plantation,which could be used as the ecological restoration tree in the soft sandstone area.In conclusion,the stability of soil microecological environment in P.tabulaeformis plantation is higher than that in the other ecological restoration vegetation types,which is the better ecological restoration vegetation in the arsenic sandstone area.Arbuscular mycorrhizal fungi,actinomyces and available nitrogen regulate coordinately the changes of environmental restoration in the rhizosphere soil microecological environment,and soil total phosphorus content restrict the rhizosphere soil microbial community structure.