Response Of Alpine Meadow To Summer Grazing In Different Degradation Grades In The Upper Reaches Of Datong River

Alpine meadow is one of the main grassland types in the Qilian Mountains in the upper reaches of the Datong River.It has the advantages of rich forage species,high proportion of fine pasture,and high grassland yield.It is also an important source of water conservation and is the basis for local herders to survive.It has important significance in ecological environmental protection and improving the lives of herders.In recent years,in order to maximize the economic benefits,pastoralists have been overgrazing for a long time,and grassland degradation has intensified.To study the vegetation characteristics and soil physical and chemical characteristics of alpine meadows with different degraded grades in summer,aiming at providing theoretical guidance for rational grazing of alpine meadows with different degraded grades.The test site is located in the summer pasture of Wajitun Village,Moer Town,Qilian County,Qinghai Province.The research was carried out according to the conventional ecological test methods.The main findings are as follows:1.The order of grazing affecting on plant height of different degrees of degradation is: mild degradation > moderate degradation > severe degradation > extreme degradation;Under the influence of grazing,the coverage of Cyperaceae decreased significantly(P<0.05),but there was no significant difference in total vegetation coverage,gramineae,leguminous and miscellaneous grass(P>0.05).The order of grazing on the Shanon-Wiener index and Simpson index of grassland with different degrees of degradation was: mild degradation > severe degradation > moderate degradation > extreme degradation,and the order of impact on the Pielow index was: mild degradation > moderate degradation > severe degradation,Extremely degraded.2.The results of the two years of grazing showed that the feed intake of the fine grass was decreased in order from mild degeneration,moderate to severe degeneracy,and in the livestock,but the feed intake rate was in the opposite trend and gradually increased.The order of the influence of grazing on the amount of aboveground plants in different degraded grassland was: severe degeneration> moderate degeneration> mild degeneration> extreme degeneracy.3.The order of impact of grazing on the amount of underground plants in different degraded grassland is: severe degradation > mild degradation > moderate degradation > extreme degradation;the effects on soil water content and soil bulk density of different degrees of degradation are: mild degradation >Severe degradation>Moderate degradation>Extreme degradation;4.Under the influence of grazing,there were no significant changes in nutrients of mild degradation,moderate degradation,severe degradation and extreme degradation(P>0.05).