Effects of Different Grazing Intensity on Population Characteristics and Nutrients of Deyeuxia angustifolia Meadow in the Initial Grazing Stage

The experiment was conducted in Deyeuxia angustifolia meadow with local cattle for 5years.Grazing intensities were heavy grazing,moderate grazing and light grazing,respectively.No grazing group was used as a control group.The experiment aimed to observe the effects of different grazing intensities on the population characteristics and nutrients of D.angustifoliain the early stage of the following grazing year(May 15th)and analyze the regulars of variation.The results showed that:with the increasing of grazing intensity,the height,vegetation coverage and hay yield of D.angustifolia were significantly decreased(P0.05).Compared with CK,the height of D.angustifoliain HG,MG and LG,reduced by 22.95%,16.03% and 7.54% in average,respectively;the vegetation coverage reduced by20.38%,12.25% and 5.53%in average,respectively;the hay yield reduced by 47.35%,44.29% and35.81%in average,respectively.But the density of D.angustifoliain HG areas increased by 3.02%,in MG areas and LG areas reduced by 30.53%and 36.34%,respectively.Height and hay yield of D.angustifoliabetween different grazing years had no significant difference,but the vegetation coverage and density of D.angustifoliatended to decrease with the increase of grazing years.Along with the increase of grazing years,the content of crude ash,neutral detergent fiber and acid detergent fiber of D.angustifolia both increased,and the content of crude protein and crude fat decreased.