Study on Change of Soil Microoganisms、Soil Enzyme and Its Relationships with Soil Factors on Microbiotic Soil Crusts in Horqin Sand Land, Inner Mongolia
|School||Inner Mongolia Normal|
|Keywords||Horqin sand land Microbiotic soil crusts Soil Microbes Soil enzyme actives Soil factors|
This paper was conducted to study on the kinds of vegetation plots and biological soil crusts in moving dunes, semi-fixed dunes and fixed dune on southeastern Naiman in Horqin sand land, Inner Mongolia. It was found that there were algal crusts with blue-green algae and green algae, as the main taxa, in semi-fixed sand dune. Besides algal crust, there were moss crusts, most of which were bryophytes, in the fixed sand dune, However, the formation of the algal crust dominant species are almost the same in fixed sand dunes and semi-fixed sand dunes , but the species are slightly different. We have studied the seasonal dynamics of the different stages of biological soil crusts and soil microbe quantity、soil microbial biomass carbon, nitrogen, soil enzyme activities and soil factors of the lower layers, and the relativity among them. The results are:1.Microbe quantities in different kinds of plots in Horqin sand land all show that bacteria >azotobacter >actinomyceto> fungi. Microbe quantities of different soil layers are slightly different. The microbe quantities of the moving dunes are the most plentiful in the lower floor of top layer, and that the top layer soil microbe quantities of the fixed and semi-fixed sand dunes are the most , and reduces gradually with increase of the soil depth. Microbe quantities of the different seasons are different, that is Summer >Autumn > spring > winter. And the four kinds of soil microbe quantities dynamic change differently each season in the respective soil layer of each plots, the bacteria and azotobacter quantities are the most in summer and autumn, whereas actinomyceto and fungi quantities are the most in autumn and summer, and the four kinds of microbial quantities are the least in winter .2. MBC, MBN and microbe quantities are positive correlation, that is GX>GZ>GW>BZ>BW>L. The MBC and MBN content of the different depth is different. Except the moving dunes, the content of MBC、MBN is the highest in the of top layer in the other kinds of plots, and reduce sharply with the increase of the soil depth. The MBC and MBN content of the moving dunes is nearly the same each season, but there are prominent and even extremely prominent seasonal differences in the other plots. MBC, MBN content is most high in autumn, secondly is summer, spring, the content is the lowest in winter.3.The three soil hydrolases (urease, protease and invertase) have a prominent difference (P<0.05) in different kinds of plots, that is GX>GZ>BZ>GW>BW>L. Except moving dunes, in the other kinds of plots, soil hydrolase activity is reduced with the increase of the soil depth, and compared with under 3cm soil layers, the top layer is the prominent or extremely prominent difference. At the same time, three soil hydrolases are also different each season.As to hydrolase, the polyphenol oxidase activities in different kinds of plots are that GX>GZ>GW>BZ>BW>L. The oxidase activities,which are much similar to hydrolase, are reduced with the increase of the soil depth, and there are the seasonal differences at the same time.4. Soil moisture and pH are different in the different kind of plots, but not obvious. As the moving dunes evolved towards the semi-fixed sand dunes, fixed sand dune, the biological soil crusts emerged. In the process of development, the coarse sand content decreased gradually, fine sand content gradually increased, and when there were biological soil crusts, the silt emerged. From section plane of the structure, biological soil crusts should better improve soil particle on the top layer than below the soil surface.With the sand dune fixed and biological soil crusts emerged and developed, except total potassium, the soil organic carbon, organic matter, total nitrogen, total phosphorus and other soil nutrients substantially increased. Biological soil crust increased soil nutrients, improved soil fertility. And the range of soil nutrient content with the seasonal changes were obvious differences.5. Bacteria and the total number of soil microbes have correlation significantly with MBC、MBN, the rest up to very significantly. The soil microbe quantities have a positive correlation with soil enzyme activity. The surface soil organic matters, organic carbons, total nitrogens as well as total phosphorus have different degrees of relevance with soil microbes,soil enzymes activity and soil particles. The results show that soil microbes, soil enzymes and the various soil factors are interdependent and affect each other.