Responses of dominant plant nutrients to grazing intensity in Kobresia pygmaea meadow of the QinghaiTibet plateau

Effects of grazing intensity disturbance on nutrition characteristics of dominant species Kobresia pygmaea and Stipa purpurea in Kobresia meadow of the QinghaiTibet plateau were studied. The results showed that there were differences on responses of plant nutrients to different grazing intensity between these two dominant plants. Grazing had the benefit of calcium and phosphorus absorption for the plants. Heavy grazing significantly (P＜0.05) increased calcium and phosphorus absorption of K.pygmaea compared to moderate grazing and control. The changes between the moderate grazing and control were not significant (P＞0.05). The calcium content of S.purpurea followed a trend of heavy grazingmoderate grazingcontrol, while the phosphorus content increased firstly and then decreased with the increasing grazing intensity. It was also found that grazing reduced significantly (P＜0.05) the forage crude fiber content and increased contents of the forage crude protein and crude fat. Grazing livestocks promoted the compensatory growth of the plants, accelerated grasssoil nitrogen cycles, increased pasture nitrogen uptake and increased the forage crude protein content, so that grazing improved the forage quality in Kobresia meadow of the QinghaiTibet plateau.