Enclosing Years On The Soil Bacterial Diversity Of Songnen Grassland

Songnen grassland is one of the most important renewable resources in Jilin province, the degradation of the grassland has resulted in serious consequences to the utilization and recovery updates of Jilin province resource, take effective measures for the rehabilitation and reconstruction has the incomparable role to the production and ecological degradation of grassland, and has urgent needs. Natural grassland is one of the main terrain grazing, over grazing have serious burden to the grass, for the restoration and reconstruction, enclosure has been adopted by many countries in the world. This paper is mainly the study of the recovery of degraded grassland in Songnen grassland, Chloris virgata, Leymus chinensis and Artemisia scoparia single dominant community of field samples and laboratory analysis, the application of modern ecology method and PCR-TTGE modem biological technology, compare the exclosure period were3years,8years on the Songnen grassland soil physical and chemical properties,microbial biomass and soil bacterial diversity, and to sample the free grazingplots as control, the main conclusions are as follows:(1)During the process of restoring succession, the content of increase total nitrogen and organic matter increases, pH and the content of water-soluble salt decreases; with the enclosing years increased, the content of total nitrogen from lower soil decreased, the content of ammonium nitrogen and nitrate nitrogen from Artemisia scoparia decreased, the content of ammonium nitrogen and nitrate nitrogen from Chloris virgata increased; the content of total nitrogen and organic matter from upper layer of soil is higher than the lower soil, water content is contrary,the content of available phosphorus in Leymus chinensis community and Artemisia scoparia community in the upper layer soil was higher than it in the lower soil water content.(2) The microbial biomass of the soil samples from Artemisia scoparia community fencing for8years the lower soil is up to510.99mg/g.(3) The total microbial DNA extraction of fragment size was about23kb,, effectively remove phenol, RNA, protein and other pollution.(4) The bands of TTGE atlas from enclosing3years, enclosing8years and free grazing in the0-20cm soil samples is less than20-40cm soil samples.Chloris virgata community, the bacterial community structure from0-20cm soil samples is similar, different from the samples in enclosure20-40cm soil,the bacterial community structure is completely different from the20-40cm free grazing area soil samples, in Chloris virgata community, enclosing years had some effects on bacterial community structure of20-40cm soil samples. Artemisia scoparia community, the similarity of20-40cm soil samples is not high,0-20cm soil samples,the similar value of the soil sample of enclosing8years, soil sample of enclosing3years and free grazing area is0.64, although has the distinction, but also has good similarity.Leymus chinensis community, the similarity of bands in20-40cm soil samples has little difference, is similar to0-20cm soil samples enclosed for8years, and is not highly similar to the soil samples from0-20cm enclosed for3years and free grazing area, in Leymus chinensis community, enclosing years has a certain influence on the structure of bacterial community in20-40cm soil.(5)The soil physical and chemical factors has correlation, the richness is related to the content of total nitrogen, available phosphorus, organic matter and water content of soil, the diversity index is related to the content of total nitrogen, organic matter, water content and species richness, total nitrogen content, pH value and soluble salt content is associated with the surface vegetation.