Effects Of Different Rest-grazing On Typical Grassland Plant Communities And Soil Stoichiometry

The typical grassland in Inner Mongolia is a temperate semi-arid grassland type,which is sensitive to human activities and climate change.Long-term overgrazing affects the development of animal husbandry and causes serious grassland degradation.In order to study the effect of grazing rest time on grazing grassland,this study was conducted in Maoden Ranch,Xilinhot,Inner Mongolia,in 2012.After six years of continuous grazing experiment and sampling in 2018,the effects of different rest periods on plant community and soil nutrient and metrological characteristics in the growing season of typical grassland in Inner Mongolia were studied.The conclusions are as follows:1.Different grazing time can reduce the height and coverage of the whole community and species richness,but can increase the density of the community.Grazing in early spring and summer can not only better maintain the species diversity of the community,but also increase the evenness of the community.2.Different populations responded differently to grazing rest.Leymus chinensis population: enclosure is more conducive to the increase of Leymus chinensis population height and biomass;Stipa krylovii: grazing in spring and summer is conducive to the increase of density and biomass of Stipa krylovii;Cleistogenes squarrosa: different grazing time control can increase the density and biomass of Cleistogenes squarrosa,of which spring grazing has a significant impact.3.Resting grazing in early spring and summer and resting grazing in spring and summer promoted C/N,C/P and N/P in shallow soil layers(0~30 cm),and the correlation between totalcarbon and total nitrogen was high.Soil total carbon and nitrogen were positively correlated with C/P and N/P(P < 0.01),and soil C/P was positively correlated with C/N and N/P(P< 0.01).4.From the net primary productivity of the community and the total feed intake of the sheep in that year,rest grazing in early spring and summer(starting grazing in June)is the best way to regulate the rest grazing;the storage rate,grassland utilization rate and livestock feed intake in early spring and summer are the best way to regulate the rest grazing in different time.