| It can reflect dynamic change of organic carbon and nitrogen in soil very well by means of cultivation, isolation and characterization of cultivatable microorganisms in soil. And at the same time, we can control the quality of soil by measuring the number of cultivatable microorganisms. Therefore, the study researches the temporal and spatial distribution and the characteristics of number and species of cultivatable microorganisms in soil. And the main study is the association of the different kinds of cultivatable microorganisms to the dynamic changes of soil organic carbon and inorganic nitrogen’s content. The study has the important meaning on the change law of the variation of soil organic carbon and inorganic nitrogen and the realization of monitoring to black soil quality. We get the following conclusions though the research:(1) The bacterial flora in black soil are constituted of twenty species:Bacillus subtilis、 B.mycoides、Pseudomonas pseudoaicalogenes、P.stutzeri、Acinetobacter johnsonii and so on. The dominant genera are eight species:Arthrobacter citreus、Ar.globiformis、Agrobacterium radiobacter var. Ⅰ. Ps.pseudoalaligenes、Ps.fluorescens var. Ⅰ、Bacillus subtilis、B.mycoides、 Cellulomonas fimi. And we separate nigh species of the genus of causal fungi. The dominant species are Aspergillus niger、Pencillium expansum Phoma nebulosa、P.putaminum. The main actinomycetes consist of seven species:Streptomyces albus、MeiGuiZi Streptomyces、 S.caeruleus、S.chromfuscus and so on. And Streptomyces albus、S.caeruleus、S.chromfuscus、 Nocardia rubropertincta、Nocardia convolute are confirmed the dominant species.(2) The distribution of the number of bacteria、fungi and actinomycetes in black soil appears obviously seasonal and spatiality with sampling time. Along with the increase of the depth of sampling, the number of cultivate microorganisms in black soil in each sampling time is in performance declines, and the content of organic carbon is also in performance declines in deep of0-20cm, which is the most obviously in August. And it is to be balance at the last time. The change of HA and FA is so. But it isn’t so obviously than organic carbon.(3) Along with the increase of dilution factor of medium, the tendency of the specie and content of microorganisms declines continuously, which indicates it can reduce the specie and survival amount of microorganisms in poor nutrition conditions, and the specie and count of microorganisms increase at the first until to be steady.(4) The microbe quantity which inoculated to sterile soil show a quickly rising trend, when they reach a certain degree, they begin to show the falling current, at last they tend to equilibrium. It is the fastest decline that the content of organic carbon in non sterile soil. Followed is sterile soil that inoculated bacteria. Therefore, the effect on organic carbon in sterile soil which added fungi and actinomycetes reach to the significant difference levels. Along with the increase of the culturing time, the content of organic carbon, HA and FA in non sterile soil decreased gradually especially, so dose the sterile soil which added bacteria. Fungi and actinomyces can also reduce the content of organic carbon, but doesn’t reach significant level.(5) Microorganisms can increase the content of inorganic nitrogen significantly in soil. It plays an important role in the change of the inorganic nitrogen in black soil. And bacteria in cultivate microorganisms contribute to inorganic nitrogen tremendously. The level of the relativity of microbial biomass, organic carbon, HA, N-NO3and N-NH4reaches difference notable. But the level of the relativity with FA isn’t notable. |
PDF Full Text Request