Effects Of Grazing On Productivity,Nutrient Content And Ecological Stoichiometry Feature Of The Typical Grassland Communities

Typical grasslands in Inner Mongolia are China’s major animal husbandry bases.In recent years,the main way of grazing is based on rotational grazing with family ranch as a unit.In this study,the typical grasslands of Stipa grandis and Leymus chinensis in Xilinhot,Inner Mongolia are used to measure and analyze the responses of community biomass,biodiversity,soil nutrient content,flora community and major population nutrient content and their stoichiometric characteristics to mild,moderate and severe grazing in four years.The results of this study can be a reference for the study of grazing ecology theory and the practice of grassland sustainable use.The main findings are as follows:1)The average biomass of the growing season is significantly reduced by mild,moderate and severe grazing after four years;and the average biomass is reduced by 20%,22%and 41%,respectively,after four years of grazing.2)The effects of grazing on the biomass of communities have seasonal differences;biomass of the severe grazing community is significantly reduced,while biomass of mild and moderate grazing communities has no obvious changes.However,the biomass of the moderate and mild grazing communities decrease significantly in other months.3)Grazing changes biomass of the main populations in communities.The biomass of Stipa grandis population increase significantly with the increase of grazing intensity.The biomass of Leymus chinensis and Anemarrhena asiatica decrease with the increase of grazing intensity,and biomass change of the Cleistogenes squarrosa is not significant.4)Grazing has a significant effect on the diversity of the communities,and the Shannon-wiener index and pielou evenness index of moderate and severe grazing communities decrease significantly.5)After four years of grazing,grazing intensity does not affect soil organic carbon,total nitrogen,total phosphorus,available nitrogen and available phosphorus,and has no significant effect on C,N and P nutrient content of the entire communities.6)The responses of plant nutrient content and its stoichiometric characteristics to grazing have interspecific differences.Grazing almost has no significant effect on nutrient content and chemometrics of the Stipa grandis and Leymus chinensis,but has effects with different extents on the latent Cleistogenes squarrosa and Anemarrhena asphodeloides.