Response Of Vegetation Community Character Stic And Soil Physico-Chemical Properties GR Zing Intensity On Kobresia Pygmaea Meadow Of Qinghai-Tibet Plateau

The field observation station located at Gongbo’gyamda County,Nyingchi Prefecture,Tibet Autonomous Region,China. In recent years,the alpine meadow degradated seriously and the development of animal husbandry is restricted. In this experiment was investigated the response mechanism of alpine meadow vegetation and thesoil because ofgrazing,based on the most representative kobresia pygmaea meadow of alpine meadowin Tibet Plateau. The research result show that:With the increasing grazing intensity, Kobresia pygmaea meadow() plant communities changed significantly. There have been no significant changes in community coverage and plant diversity throught Zero herding (CK) and moderate herding (MG)(P>0.05), but severe herding (HG) that community coverage and plant diversity changed significantly (P<0.05). With the increase of the pressure grazing,the height of purple flower barbate needlegrass significantly reduced(P<0.05).With grazing pressure increased,soil organic matter, nitrogen, phosphorus and available phosphorus decreased in0~30cm soil.Under moderate grazing, total phosphorusand available phosphorus in10~20cm soil significantly increased and the differencereached a significant level (P <0.05) compared with the control and heavy grazing. Under the different grazing intensities,the content of soil available trace elements suchasFe, Mn, Cu and Zn reached significant level (P<0.05). Under different grazing intensities,the content of soil trace element in Alpine Meadow is different,in the order of Fe> Mn> Zn> Cu content.The content of purple flower barbate needlegrass total nitrogen and kobresia totalphosphorus increased significantly(P<0.05),and the purple flower barbate needlegrass total phosphorus content reached the maximum and significant level with moderate grazing condition,but the content of crude fat in kobresia is reduced.Under heavy grazing, tibetan yak weight decreased significantly,1%less than moderate grazing. The reasonable stocking content of kobresia pygmaea meadow of alpine meadowin Tibet Plateau is0.35head of yaks per hectare, more than this threshold, grasslands degraded severely degraded...