Effects Of Different Land Use On Soil Microbial Diversity In The Horqin Meadow Grassland

In order to discuss the soil microbial diversity of different land use in the Horqin Meadow Grassland, chose five different land use (paddy field, woodland, natural meadow,4-year and30-year farmlands) as the objects. With the methods of phospholipid fatty-acid analysis (PLFA), Biolog (ECO, GN and GP microtiter plate) analysis and denaturing gradient gel electrophoresis (DGGE) adopted, soil microbial diversities of community structure, function and inherit in different land use were studied, which is expected to provide the scientific evidence in rational use and recovery of Horqin meadow.The results show that compared with the farmland and paddy fields, the species and content of soil microbe are richer in natural meadow and woodland, but the dominant species are similar. Among different utilization patterns, the differences of biomass of gram-negative bacteria are not remarkable, yet the differences are mainly focused on Gram-positive bacteria. Ratio of bacteria and fungoid are as following:natural meadow>4-year farmlands> woodlands> paddy fields>30-year farmlands, which shows that, With the conversion from natural grasslands to other utilization patterns, abundance of microbe populations decrease, the conversion of soil microbiota from bacteria to fungoid.The soil microbe in different land use using the analysis of ECO, GN2and GP2plates shows the soil microbe function diversity rules are not entirely consistent. According the analysis of ECO, GN2plates, soil microbe biocenosis in30-year farmlands have the most strong average metabolic activity,4-year farmlands are on the contrary. Yet that of GP2are firstly woodlands, secondly natural meadow and paddy fields,30-year farmland lowest. The use ratio of carbon sources of soil microbe biocenosis in different land use in sugar, carboxylic acids and amino acid are significantly higher than that of polymer analogue, amine/ammonia and parents of compounds. The contributions of various carbon sources are different to functional diversity of soil microbe biocenosis, in which the bacteria types using amino acid, sugar and carboxylic acids are dominant bacterium groups.Different land use in the Horqin Meadow Grassland, soil microbe shows some fixed inherited diversity. Due to the long unique cultivation and management measures, paddy fields form some characters different from the dry soil, which are quite different from other soil samples.8of16recovered bands sequencing results are uncultured bacteria. From which we can see that there are a large number of uncultured soil bacteria. The dominant bacteria in five tested soil samples mainly contained proteobacterium, Actinomycetales, Gemmatimonadetes, Vibrio sp., Enterobacter sp., Shigella sp. and Escherichia sp..