The Research On Soil Nutrition And Relationship With The Composition Of The Microbial Communities In Different Forests Of Changbai Mountain

The investigation of plant species diversity of five different forest types had been studiedin Changbai Mountain forest region (the virgin forest, red pine plantation, pine and broadleafmixed forest, birch secondary forest, Pinus sylvestris), and cultured different types forest soil,measured culture and natural level of the soil microbial community structure and biomass, aswell as the soil nutrients index of different forest types in both environmental states. Study ofthe relationship between aboveground plant species diversity in different forest types and soilmicrobial community composition and biomass; the impact of soil properties (including C, N,P and pH) on soil microbial community composition and biomass, acquired the conclusions asfollow:1. Birch secondary forests had been proved as the maximum specie number of91kinds ineach forest type; Pinus sylvestris as the minimum which only conclude18species; thediversity index of natural forests was larger than the plantations, especially in the naturalforest arbor layer of which diversity index was much larger than the plantation;2. Natural state, the relation between TPLFAs species number and the other five forest typesshown a positive correlation, and Shannon-Wiener index, Simpson index and Pielouindex was respective nonsignificant positively correlated, indicating that the plantdiversity of the natural state is an important factor impacting the microbial characteristicfatty acid biomass;3. The bacteria expressed higher proportion in the cultivate condition than the naturalconditions, and fungi/bacteria reflected the contrary state. The percentage of fatty acidsand monounsaturated fatty acids mole mass in cultivating environment was much higherthan natural conditions. This shown that the fungi had better existence in the state ofnature, in the nature condition with great nutrition pressure, the stress-resist ability ofbacterial communities is stronger than the fungal communities; but in the naturecondition with less nutrition pressure, fungal communities yielded higher growth abilitythan bacterial communities;4. As a whole, the relationship between the proportion of10Me18:0—actinomycetescharacteristic fatty acid and the influence of soil TN and OC was significant negativecorrelation, the change impacted the different forest communities microbial composition;alterations in the18:1ω7c proportion will affect the proportion of the bacterialpopulation in the entire microbial community, thus changing the structure of the entiremicrobial community;5. When external nutrient resource was cut off，the microbial community characteristicfatty acids of natural forest types with high plant diversity changed over time mainly dueto the alterations of nitrogen.