Study On Influence Of Disturbance Manners To Typical Steppe Vegetation And Soil

The research was carried out four experiment sites that grazing land, mowing land, enclosed land 1(enclosed since 2002 and mowing ), enclosed land 2(enclosed since 1989 and mowing ) on the typical steppe of taipusi Inner Mongolia and the landform, physiognomy, original vegetation was consistent according field survey, recordation and investigation. The objective of the experiment is to research variation characteristic of vegetation and soil under different manners and analysis succession orderliness and probe into condign utilization and management manners and offer gist for utilization and management. The results as follows:1. The total coverage gradation of different disturbance manners is that enclosed land 2>mowing land>enclosed land 1>grazing land. The hay product gradation of different disturbance manners is that mowing land>enclosed 2>enclosed 1>grazing land. The underground biomass gradation of different disturbance manners is that enclosed 2>enclosed 1>grazing land>mowing land.2. The value of grazing land vegetation height is less than that of the exclosure land, the Gramineae density and coverage value of grazing land is the least. The Leguminosae height, density and coverage value of exclosure land higher than that of grazing land and mowing land obviously but the Ranunculaceae and Thymelaeaceae density value is less than that of grazing land and mowing land. The grazing land dominant vegetation community restoration succession process is Potentilla acaulis + Artemisia frigida + Cleistogenes squarrosa because of grazing serious. The mowing land dominant vegetation community restoration succession process is Leymus chinensis + Serratula centauroides. The exclosure land dominant vegetation community restoration succession process is Leymus chinensis+ Stipa krylovii+ Cleistogenes quarrosa because of exclosure utilization.3. The enclosure land species number is the best among the disturbance manners and the grazing land species number is the least. The enclosure land value of Margalet index and Shannon—Wiener index and Peilow index are higher than that of mowing land and grazing land. The maximum of vegetation similar index is 0.44 between grazing and mowing land, and the minimum of vegetation similar index is 0.41 between grazing and enclosure land 2.4. The soil nutrient content of different disturbance manners is that total reduce along with depth increase and enclosed land nutrient content is higher than that of the grazing land and mowing land. The soil seed bank density result is that: enclosure land 2(6689.8±912.1)seeds·m-2>enclosure land 1(6468.4±1027.2)seeds·m-2>mowing land(5533.7±996.8)seeds·m-2>grazing land(3724.3±1217.6)seeds·m-2. The maximum Sorensen index is 0.37 (1989 enclosure land) and the minimum Sorensen index is 0.32(mowing land).5. Compare with the different disturbance manners lands with grayness relationship analysis. The analysis result is that: enclosure land 2 (0.9252) > enclosure land 1(0.8167)>mowing land (0.7329)>grazing land (0.6941). It shows that the disturbance manner of enclosure and mowing is more benefit to grassland resources utilization and protection than that of the long-term grazing and mowing. Avoid mowing long-term after enclosure to prevent grassland degradation succession.