Effects Of Seasonal Delaying Grazing On Vegetation And Soil Under Different Grazing Intensities

The natural meadow steppe in the horse farm of Zhao Su, Ili Kazak Autonomous Prefecture inXinjiang, was selected as the research object in this experiment. Three different grazing intensities, lightgrazing (LG,0.38head/hm~2), moderate grazing (MG,0.63head/hm~2) and heavy grazing (HG,0.88head/hm~2) were tested on Spring (B1, from June to July), summer (B2, from July to August) and autumn (B3,from August to September) in the year of2011to2012. Through the investigation on vegetation and soil,measuring and analyzing of seasonal grazing under different grazing intensities, aimed at providing ascientific basis for sustainable use of the natural grassland, so as to reveal the best model of grazing in thisregion. The main results are as follows:1、The effects of seasonal delaying grazing on the quantitative characteristics of grassland plantcommunities under different grazing intensitiesThere were some certain short-term seasonal delaying grazing impacts on the height, coverage, density,biomass and abundance of grassland plant communities, as it was expressed that the delaying grazing areawas better than the grazing area. While in the height and biomass, it was shown that the delaying grazingarea was significantly better than the grazing area, especially in the spring grazing area under medium andhigh grazing intensity, it was more obvious(P<0.05). Otherwise, the difference in height, coverage anddensity of grassland communities under different grazing intensities was not significant (P>0.05).2、 The effects of seasonal delaying grazing on the nutrition quality of grassland plantcommunities under different grazing intensitiesGenerally speaking, seasonal delaying grazing has little effect on the content of chemical compositionof the grass plants. There was no big difference in the content of most plants between delaying grazing areaand grazing area. Compared with the first year of delaying grazing grassland, the nutrition index ofgrassland plant had improved to varying degrees on the second year. It was preliminarily confirmed thatseasonal delaying grazing could improve the nutrition quality of the grassland plant under different grazingintensities.3、The effects of seasonal delaying grazing on the nutrition of dominant species in grasslandplant storage under different grazing intensitiesThe soluble sugar and starch content of the grassland dominant species was no much difference inseasonal delaying grazing and grazing area under different grazing intensities. Soluble sugar content of themain dominant species of plant roots showed that soluble sugar content of Medicago falcate L.was higherthan other dominant species in seasonal delaying grazing area under different grazing intensities. Thecontent of starch showed that Medicago falcate L. in the spring delaying grazing area was higher thangrazing area under different grazing intensities.4、The effects of seasonal delaying grazing on the physical and chemical properties underdifferent grazing intensitiesWith the depth of soil increasing under different grazing intensities, pH increased, content of organicmatter and available N, P and K decreased both in delaying grazing and grazing area. The change of soilnutrient content in delaying grazing and grazing area under different grazing intensities showed that therewas little change in the two areas, but the organic matter, nutrient in full effect and the available Nincreased.These results indicated that the implementation of seasonal delaying grazing under different grazingintensities was conducive to improving the index of grassland plant communities, improving the nutritionalquality of the grass plants, increasing grass plant storage material content and improving grassland soil to acert2ain extent. it could be preliminarily determined no grazing under light grazing pressure (LG,0.38head/hm), spring delaying grazing (B1) under medium grazing pressure (MG,0.64head/hm~2), and spring andautumn grazing (B1and B3) under high grazing pressure (HG,0.89head/hm~2). Thus it could providesignificant guidance for improving the productivity of grassland vegetation and restoring the degradedgrassland.