Study On Characteristics Properties Of Soil Microbial Communities Of Small Gansu Mountain National Nature Reserve

Xiaolongshan Mountain National Nature Reserve is located in the southeastern,belonged to the northern temperate subtropical transition zone. XiaolongshanMountain forest area in the maintenance of the western Loess Plateau and the YellowRiver, Yangtze River region ecological balance, protection of biodiversity, flood water,sand-fixing, improving the environment, an irreplaceable role. Thus Xiaolongshanforest area of the characteristics of soil microbial communities, can reveal the forestlaw of the soil habitat restoration has important theoretical and practical value.The article took Baihua Forest Farm in Xiaolongshan, Tianshui City as the study areaand collected soil samples from quercus acutidentata forest, mixed coniferous broadleaved forest, pinus tabulaeformis forest and Japan pine leaves forest. Through theanalysis of soil sample, it made a research on the soil environment characteristics ofdifferent kinds of forests, such as soil organic matter, available nutrient （availableNPK） and soil pH. Besides, it also studied the soil microbial community characteristicof different kinds of forests, such as microbe quantity and distribution characteristics,function flora composition and quantitative properties and layer ratio. The results areas follows:（1） characteristics of the soil environment in the different vegetation:a. soil nutrientdifferent distribution of soil nutrients:①the soil distribution: aspects of organicmatter, sharp tooth oak> Chinese pine> Japanese larch> broadleaved mixed forest:available N, P, K content: distribution of forest types of soil available N: Chinese pine> Japanese larch> sharp tooth oak> broadleaved mixed forest; soil available phosphorusdistribution: Chinese pine> Japanese larch> sharp tooth oak> broadleaved mixedforest: soil potassium distribution: broadleaved mixed> Japanese larch> sharp toothoak> Chinese pine.②Vertical distribution: organic matter and soil potassiumexpressed as the surface of the highest, with the deepening of the soil depth is reduced,and the available nitrogen and available phosphorus was not significant. This iscaused mainly by the different levels of the vegetation, topography, human activitiesand other factors.b. soil ph valueXiaolongshan Mountain National Nature Reserve four forest types in soil phvalue is in the range between6.04to6.56, the following order: Chinese pine> Japaneselarch> sharp tooth oak> broadleaved mixed forest. It is because litter decompositionproduced more organic acids, and the sake of the litter to reduce soil ph value.（2） quantitative characteristics of soil microbial communities in different vegetationThe total number of the broadleaved mixed forest soil microbial communities was806.188×10⁵cfu·g^-1dry soil, where the number of the bacteria was805.51×10⁵cfu·g^-1dry soil, the actinomycetes was0.575×10⁵cfu·g^-1dry soil, the fungus was0.103×10⁵cfu·g^-1dry soil. The total number of the Japanese larch soil microbialcommunities was2311.681×10⁵cfu·g^-1dry soil, where the number of the bacteria was2310.65×10⁵cfu·g^-1dry soil, the actinomycetes was0.694×10⁵cfu·g^-1dry soil, thefungus was0.337×10⁵cfu·g^-1dry soil. The total number of the Chinese pine soil microbial communities was2544.222×10⁵cfu·g^-1dry soil, where the number of thebacteria was2543.00×10⁵cfu·g^-1dry soil, the actinomycetes was1.068×10⁵cfu·g^-1drysoil, the fungus was0.154×10⁵cfu·g^-1dry soil. The total number of the sharp tooth oaksoil microbial communities was7295.452×10⁵cfu·g^-1dry soil, where the number ofthe bacteria was7292.34×10⁵×10⁵cfu·g^-1dry soil, the actinomycetes was1.877×10⁵cfu·g^-1dry soil, the fungus was1.235×10⁵cfu·g^-1dry soil. The order of thetotal number of the four forest types is sharp tooth oak> Chinese pine> Japanese larch>broadleaved mixed forest.（3） distribution characteristics of soil communities in different vegetationOn every soil profile, soil microbe quantity of0-10cm is the largest. However,with the deepening of soil depth, the microbe quantity and richness is becoming lessand less. The amount of soil microorganisms in different vegetation form and threegroups have shown a great vertical distribution on soil profile. Soil microorganismsquantity of the surface is the largest, the middle part is the second largest and lowerlevel is the least.（4） The composition characteristics of the functional bacteria of the differentvegetation soil microbial communitysharp tooth oak, Chinese pine, Japanese larch and broadleaved mixed forest were mainlycomposed of aerobic nitrogen-fixing bacteria, phosphate solubilization bacteria,solution of potassium silicate bacteria, aerobic cellulose decomposing bacteria. Theorder of the total number of the four forest types is phosphate solubilization bacteria>aerobic nitrogen-fixing bacteria> solution of potassium silicate bacteria> aerobiccellulose decomposing bacteria.（5） soil stratification ratio in different vegetationThe soil stratification ratio of the bacteria, actinomycetes and fungus was from1.23to4.31. There was no abnormal high or low position, which corresponds to the totalnumber of microorganisms. However, The coordinated development of differentmicrobial population stratification ratio indicates soil quality to be furtherinvestigated.