Effect Of Grazing Intensity On Community Functional Diversity Of Soil Bacteria In Songnen Grassland

Grazing is the most important way for utilization of Songnen grassland. In order toobtain information in which grazing way can result in better soil properties and soilbacteria properties, the Biolog-ECO microplate was used for researching the changesof vegetation characteristics and carbon source utilization of soil bacteria communityin rhizosphere of Leymus chinensis with three grazing intensity (no grazing, lightgrazing and heavy grazing) under short period conditions. In this paper, the changecharacteristics were further researched in light grazing situation, which belong tocommunity functional diversity of soil bacteria in rhizosphere of four kinds of plantfunctional group (Leymus chinensis, Leymus chinensis&forb, grass, legume). Theresults show that:1. Light grazing can’t lead to obvious change about soil physical and chemicalproperties compared to no grazing. Heavy grazing could increase soil pHand decrease the content of soil organic matter. There was no significant difference inother indexes. Grazing way can’t lead to a significant change in the physicochemicalproperties of the soil in the short term grazing condition.2. The carbon source utilization of soil bacteria increased with time, and itshowed that microbial metabolic activity enhanced with time after10days. Differencegrazing way can change the carbon source utilization of soil bacteria community, andlight grazing has the most metabolic activity, Carbon source utilization rate anddiversity index. The result of component analysis shows that using carbon source typeof soil bacteria has greater difference, light grazing utilization of carbon source type isthe most widely, which mainly use carbohydrate.3. The analysis results of soil bacteria in four grass roots with light grazingshows that bacterias of using of polymers are predominant; soil bacteria in L&forb roots have the better properties than that of other grass, which is the mostabundant utilization of carbon source type. The research results of this paper haveguiding function about selective cultivation of forage of Songnen grassland.4. Light grazing was the most appropriate grazing way in Songnen grassland. L&forb is helpful to increase the productivity of soil bacterias in the region on thebasis of light grazing, and to promote the grassland soil material circulation and nutrients conservation.