Effect of Seasonal Grazing Use on Productivity of Grassland Community

In growing season,the effect of seasonal grazing use on Leymus chinensis +Cleistogenes squarrosa +Stipa krylovii community in typical grassland of semiarid area of Inner Mongolia was studied.The results showed that:(1)During the growing season,community biomass on the ground showed a single-peak curve,and was correlated to the production of standing crop of Leymus chinensis and Cleistogenes squarrosa.(2)Grazing was stopped when the community stubble height was 6cm,the grassland utilization rate in T3treatment was the highest.In addition to the end of the growing season in September, the accumulation of net production in the period between two grazing treatment time can compensate the intaking biomass during grazing treatment period by the sheep.(3)During no grazing period,community net growth rate was higher than the CK,a widespread compensatory growth mechanism existed during no grazing period.(4)Grazing reduced root accumulation,especially in roots in 0to 30cm soil layer.