The Regulation Of Ectomycorrhizal Fungi On Soil Fertility Restoration Of Pinus Tabulaeformis Plantation

Based on the soil fertility decline of Pinus tabuliformis plantations,the effects of mycorrhizal fungi on soil fertility restoration in different types of P.tabuliformis plantations were explored for the perspective of mycorrhizal microecology.The 35-year-old pure stand of P.tabulaeformis and mixed stand of P.tabulaeformis and Armeniaca sibirica were as a research objects.The inoculated mycorrhizal fungi and no inoculation treatment were set,and the strains equal amounts of solid bacterial agents was mixed inoculation with by the 8 species excellent ectomycorrhizal fungi of P.tabulaeformis.Samples were collected in September after inoculation in spring(May)in 2 consecutive years.The indicators of soil micro-habitat,absorbing root and new leaf nutrient concentration were analyzed in different P.tabulaeformis stands.The benefits of mycorrhizal bioremediation of artificial forest land with declining soil fertility was evaluated.The results show that:(1)The Illumina MiSeq sequencing showed that there were differences in the OTU number of common and specific ecmycorrhizal fungi(ECMF)between the mixed inoculation and no-inoculation treatments.The specific OTUs number was greater in the mixed stand than that in the pure stand.The ECMF richness,Chao 1 index and Simpson index were affected significantly by inoculation treatment in mixed stand.(2)The contents of microbial biomass carbon,nitrogen and phosphorus were significantly lower in the mixed stand than those in the pure stand.Inoculation treatment significantly increased the microbial biomass phosphorus content,and the microbial biomass carbon and phosphorus contents were the highest under inoculation treatment in the pure stand.The stoichiometric ratio of microbial biomass in rhizosphere soil was significantly higher in mixed stand than that in pure stand.The microbial biomass C/P and N/P in rhizosphere soil were reduced significantly by inoculation treatment in pure stand.(3)The total nutrient concentration in the rhizosphere soil was significantly higher in pure stand than that in mixed stand.The inoculation treatment significantly increased the soil total nitrogen concentration in mixed stand and soil total phosphorus concentration in pure stand.Inoculation significantly increased the nitrate nitrogen concentration and decreased the ammonium nitrogen concentration in the pure stand and mixed stand.And organic carbon concentration was decreased significantly in the pure stand.(4)The limiting factor of soil available nutrients was changed from microbial biomass carbon to microbial biomass phosphorus after inoculation in the mixed stand.The limiting factor of available nutrients was transformed from total glomalin-related soil protein to leucine aminopeptidase after inoculation in the pure stand.(5)Under different inoculation treatments,the carbon,nitrogen,and phosphorus concentrations of new leaves were significantly lower in the mixed stand than those in the pure stand.The nitrogen concentration of new leaves was significantly increased by in inoculation treatment the mixed stand,but decreased nitrogen and phosphorus concentration in the pure stand.The absorbed root nitrogen concentration was reduced by inoculation treatment in the mixed stand.(6)The mixed stand ecosystem of P.tabulaeformis was relatively stable in rhizosphere micro-ecological environment and plant nutrient uptake aspect.And the soil fertility regulation effect by inoculation treatment was better in pure stand than that in mixed stand for the degraded ecosystem of Daqingshan Mountain.