Effect of grazing intensity on carbon source utilization of soil microorganism in rhizosphere of Leymus chinensis community in Songnen Grassland

The Biolog-ECO microplate method was employed to study vegetation characteristics and carbon source utilization of soil microorganism community in rhizosphere of Leymus chinensis under three grazing intensity (without grazing, light grazing and heavy grazing) in short period. The results showed that there were difference in the carbon source utilization of soil microorganism community in rhizosphere of L.chinensis under three grazing intensities. Light grazing can promote the growth of herbage and had the highest metabolic activity. The treatment of without grazing had the lowest metabolic activity and more microorganisms using polymers. In the matter of diversity index, the treatment of without grazing had the highest diversity index which were lower and the treatments of both light grazing and heavy grazing were similar. Principle component analysis showed that the principal carbon source of soil microorganism of light grazing and heavy grazing treatments were carbohydrate, amino acid and polymer, respectively. There was less carbon source of soil microorganism for without grazing treatment. The soil physicochemical property had important impacts on soil microorganism under different grazing intensities.