The alpine grasslands are characterized by slow growth and fragile ecological environment. The effects of different yak grazing intensity on herbage growth were studied. Experimental results showed that the yield of herbage under low-intensity grazing remained basically the same in the following three years, and the difference was not significant (P> 0.05). That is to say, low-intensity grazing not only did no harm to the pasture structure, but also had benefits. In the following three years, the yield of herbage decreased year by year with significant difference (P< 0.05), that is to say, they did great harm to grassland herbage. The average yield distribution curve of 3 years after the ban of grazing and different grazing areas presented an inverted "V" shape, and too much ban of grazing and grazing intensity had a destructive effect on the grassland, presenting a "two-way degradation phenomenon". |