Degradation Of Grassland Ecosystem In High Altitude Area Of Tibet And Its Protection And Restoration

“Protecting the ecology of the Qinghai-Tibet Plateau is the greatest contribution to the survival and development of the Chinese nation,”President Xi Jinping said at the Seventh Central Tibet work forum in Tibet.We should give more prominence to the construction of ecological civilization and turn the Qinghai-Tibet Plateau into a plateau of national and international ecological civilization,and it is necessary to promote the scientific investigation of the Qinghai-Tibet Plateau,reveal the mechanism of environmental change,accurately grasp the impact of global climate change and human activities on the Qinghai-Tibet Plateau,and put forward systematic schemes and engineering measures for protection,restoration and management.”Tibet is located on the southwestern border of China and in the hinterland of the Qinghai-Tibet Plateau.As one of the most important ecosystems in Tibet,grassland plays an important role in the national ecological security barrier and ecological civilization construction.At the same time,grassland-based animal husbandry is still the basic and pillar industry of Tibet’s economic development.With the continuous advancement and deepening of the construction of ecological civilization,more and more people are aware of the profound connotation and the concept of green development of “Lucid waters and lush mountains are invaluable assets”,The problem of grassland degradation in Tibet has attracted more and more attention of experts and scholars.According to the data,the degraded area of natural grassland in Tibet had reached2355.54×104 hm2 by 2012,accounting for 30.53% of the usable grassland in Tibet.Grassland degradation has caused significant damage to the ecological environment and economy.Therefore,it is of great significance to study the degradation and its restoration in Tibet.At present,there are a lot of studies on grassland degradation in Tibet,including those that use remote sensing technology to view the degradation situation in a large scale,and those that focus on one or several plots.However,there is an obvious gap in the study of large-scale and diverse areas,therefore,in order to understand the grassland degradation in Tibet more accurately and objectively,I consulted a large number of literature,and in order to obtain more accurate first-hand data,in May 2020,I went to the area of Naqu,Tibet,to investigate the degradation of grassland ecosystem and its protection and maintenance,In July 2020,I collected 75 soil sample points from 29 sample plots in central Tibet at an altitude of4400m-5200 m to analyze soil chemical properties,such as OM,TN,TP and so on.At the same time,I divided the grassland into high,middle and low coverage according to different vegetation coverage degree and recorded the number of species in the sample points.Numerous studies have shown that the degradation of grassland ecosystem is actually caused by the interaction of grassland vegetation degradation and soil fertility degradation,Therefore,this paper hopes to use Nonparametric test and Spearman correlation analysis to examine whether there are significant differences in soil chemical properties under different degradation degree,different vegetation coverage degree and different species number,and the correlation between soil chemical property,and finally evaluation of grassland degradation in Tibet,this paper summarizes the natural and man-made causes of grassland degradation in Tibet,and puts forward some restoration measures by finding out the problems existing in the process of grassland degradation restoration in Tibet,hoping to provide reference materials for the follow-up researchers.The main conclusions are as follows:(1)Compared with the national classification standard of soil nutrient content,the contents of OM,TN,TK,AN in the study are a were all in the extremely high level of Grade I,and the contents of TP and AK were in the high level range of Grade II,the content of AP was in the middle range of grade III;Also there was a close relationship between soil chemical properties.the pH was significantly correlated with other substances except TK and EMg.and there was a significant positive correlation between TN,AN,TP,OM,AK,EK and DOC,TK was negatively correlated with TN, ECa,EMg and DOC.(2)With the increasing of degradation degree,the contents of OM,TN,AN,DOC,TP and AP decreased significantly,and the pH increased significantly with the increasing of degradation degree;There was no significant difference among TK,AK,ECa,EMg,ENa and EK in different degradation degree.(3)Under different coverage,there were significant differences in OM,DOC,TN,AN,AK and EK,but no significant differences in other substances.(4)The results showed that there was a significant negative correlation between pH value and species number,and a significant positive correlation between OM,DOC,TN,AN,AK and EK.(5)Grassland degradation is caused by both natural and man-made causes.Through reading literature and on-site investigation,several measures for protecting and repairing grassland degradation in Tibet have been put forward,such as improve management institutions,laws and regulations,implement advanced management measures,introduce advanced technical personnel,change the backward concept of farmers and herdsmen,strengthen the construction of artificial grassland,and the treatment of poisonous weeds and pests to ensure the sustainable development of grassland ecosystem in Tibet.