Effect of short-term grazing on soil microorganisms and soil enzyme activities in Meadow Steppe

Abstract:

[Objective] In order to provide microbiology basis for protection, restoration and reconstruction of meadow steppe ecosystem in Inner Mongolian Region. To investigate the response of grassland soil microbes and enzyme activity in different grazing intensity. [Methods] Soil samples were collected from six different grazing intensity, the variation of different grazing intensities on the soil microorganisms, soil microbial biomasses (Carbon and nitrogen), soil enzyme activity and the interrelationship among them were analysised. [Results] The reseults showed that the number of microorganisms in different grazing areas had the same changing trends: bacteria>actinomycetes>fungi. The number of soil microorganisms and soil microbial biomass (Carbon and nitrogen) were higher in grazing areas than no-grazing areas. In 0?10 cm soil depth, the trend of the activities of catalase, invertase and protease was performed increased first and then decreased along with the increasing of grazing intensity, Moreover the activities of these enzymes in grazing areas was higher than no-grazing area. Compared with 0?10 cm, the descending range of the number of bacteria and fungi and the microbial biomasses (Carbon and nitrogen) were increased along with the increasing of grazing intensity in 10 cm?20 cm soil depth. The number of soil microorganism, soil microbial biomass, the activity of soil enzyme were higher in soil depth 0?10 cm than 10?cm?20 cm in the vertical distribution. Correlation analysis indicated that the number of soil microorganism was significantly correlated with soil microbial biomass. The soil enzyme activitiy was positively related to the number of soil microorganism and soil microbial biomass. The activities of catalase and invertase were extreme-significantly correlated with the number of bacteria and actinomycetes (P<0.01), and significantly related to soil microbial biomass C?(P<0.05); the activity of the protease was extreme-significantly correlated with the number of fungi and soil microbial biomass C、N (P<0.01), and significantly related to the number of bacteria (P<0.05). [Conclusion] Moderate grazing incereases soil microorganisms, soil microbial biomasses and soil enzyme activity. There were positive correlations between soil microorganisms, soil microbial biomasses and soil enzyme.