Soil Microbial And Its Affect Factors In Pinus Tabulaeformis Forestland In Haihe River Basin

Soil microorganism is a key element of forest soil ecosystem, which, as the main decomposer, plays the key role in the forest soil ecosystem. This paper researched the soil microorganism in the pinus tabulaeformis forestland in Haihe River basin. By "Grid Soil Sampling method", with collecting 57 soil samples from 5 forest in the pinus tabulaeformis forestland in Haihe River basin, analyzed the types, quantity, and distribution of the soil microorganism. With analyzing the moisture content, physical and chemical properties of the soil samples, studied the relation between microorganism and the soil basic properties, such as climates, moisture content, physical properties, as well as chemical properties, and finally learned the main factor affecting regional soil microorganism. This paper used Streptomyces albus, Bacillus subtilis, Aspergillus niger. the three commonly distributed soil microorganism. By the method of "Exogenous Microorganisms", added the three microorganism in the soil samples. After 1 year incubation, with analyzing the changes of soil water evapotranspiration amount, soil organic matter, bulk density, capillary porosity, water-stable aggregates, etc, studied the influence of exogenous microorganisms to local soil. Futhermore, by simulating soil moisture content variation, such as high mositure soil, rainfall, flood, and freeze-thaw, analyzing the relevant changes of soil microorganism, studied the influence of moisture properties to soil microorganism.Soil microbial biomass carbon in pinus tabulaeformis forestland of Haihe River basin content of 53.7-1363.59mg/kg, average 320.2mg/kg. The MBC is generally within the range of 0-400 mg/kg, which is of 73.5% of all the samples. In which, the bacteria average content is,91.7% of the total microorganism. The actinomycetes average content is 8.16% and the fungi average content is 0.14%.This paper analyzed the soil microorganism distribution regarding to variance of seasons, longitudes, latitudes, altitudes, and depth. The carbon content of soil microorganism is various in different regions.,where the carbon content is the highest in rocky mountain of north of Hebei, and lowest in rocky mountain of north of Shanxi and west of Hebei. On seasons distribution, it is summer> autumn> spring> winter. On longitudes and latitudes distribution, with longitude and latitudes increases, MBC first increasesthen decreases. On the distribution of different depth of soil layers, the microorganism mainly distributes at surface layer with depth of 0～10cm. With the increase of the depth, MBC decreases.By analyzing the relations between microorganism and the environment, this paper figured out the moisture content, physical properties, as well as organic matters of soil are the key factors affecting soil microorganism. However, there is no evidence shows MBC is affected by annual average temperature, daily average solar radiation, PH, silt, total nitrogen, toal potassium, total phosphorus, available nitrogen, available potassium, as well as available phosphorus.After the analysis of the above factors, this paper’s conclusion is that, Streptomyces albus is able to increase the organic matters, and accelerate the viporation of water in the soil. Bacillus subtilis is effective in decomposing organic matters, and decrease the soil specific gravity. Aspergillus niger could compose the organic matter, and increases the capillary porosity, which reduces the vaporation of waters, positive for the soil water retention. No matter what kind of added microorganisms, are conducive to the water-stable aggregates.For studying the influence of moistures properties to soil microorganism, this paper simulated high moisture, rainfall, flood, freeze-thaw, and found the response of bacteria, fungi, and actinomycetes to the moisture variance. The decreasing affected Aspergillus niger the most, while Bacillus subtilis the least. At beginning of the experiment, the rainfall restrained the the MBC, which however, after reaching a control point, increased rapidly. The rainfall factor affects Streptomyces albus the most, Aspergillus niger the least. With the condition of MBC reached the nadir, Bacillus subtilis was the highest reproductive, which the carbon content recovered the fastest, while the soil with Streptomyces albus needed the longer time to recover the carbon content to the original value. The flood factor affected soil with Bacillus subtilis the most, and control group the least. Freeze affected Bacillus subtilis the most, and Aspergillus niger the least. After thaw, the Bacillus subtilis recovered fastest, which is beneficial for the increasing of MBC.