Effect Of Rest-grazing On The Upper Reaches Of Datong River Alpine Grassland Vegetation

The Qilian Mountains in the upper reaches of the Datong River are covered with alpine grasslands.The area is not only rich in herbage,but also an important water conservation area.Due to long-term seasonal overgrazing.Severe degradation of alpine grassland ecosystem in this area.The production of agriculture and animal husbandry and ecological security are facing great challenges.Improvement of degraded grassland in the Upper reaches of Datong River in Qilian Mountains is urgent.The measures of rest grazing in regreen-up period can improve the vegetation,rapidly improve grassland productivity,reduce grazing pressure.Therefore,to implement the rest grazing in regreen-up period can provide theoretical basis for restoration and rational utilization of grassland vegetation It is helpful to promote the protection of grassland ecological environment and the sustainable development of economy in the upper reaches of Datong River.The study began in 2015 on the degraded grasslands in,Murle Town,Qilian County,Qinghai Province.Choose typical alpine meadows,steppe meadows,swamp meadows,and artificial grasslands were selected for rest grazing experiments,and the traditional grazing method is used as a contrast.The effects of rest grazing in regreen-up period on vegetation restoration were evaluated by measuring vegetation height,coverage and biomass.Analysis of soil improvement with the analysis of soil water content and bulk density.And providing scientific theoretical basis for the restoration of the ecosystem function of the alpine degraded grassland in the Qilian Mountains area.The main results are as follows:1.After rest grazing grazing,the important values of grasses,gramineae and cyperaceae in all types of grassland increased significantly.and the important value of forbs decreases gradually.The number of species in the community as a whole is on the rise.All types of grassland are acting in the direction of the stable state of the community.2.The plant height,coverage and biomass of alpine meadow could be increased rapidly by rest grazing in regreen-up period and inhibition of the growth and development of forbs.3.With the lengthening of the period of rest grazing,the height,coverage and biomass of gramineous grass in all types of grassland have increased significantly.Compared with the rest grazing grassland,the total biomass increased by 131.1%,415.9% and 733.7%.Rest-grazing a year,rest-grazing two year and rest-grazing three years of steppe meadow dominant species Festuca rubra than grazing grassland were increased by 36.1%,116.9% and 503.6%.The total coverage of steppe meadow communities increased by 11.2%,27.0%,48%.The Carex moorcroftii has increased by 155.9% and 212.4% for rest-grazing one year and two years.Rest-grazing can increase the biomass of swamp meadow significantly.In rest-grazing two years,the biomass of grassland increased by 220.1%.4.Rest-grazing can significantly improve the soil water content and improvement of soil bulk density of 0-20 cm.The restoration of rest grazing in regreen-up period has obvious effect on the recovery of different degraded vegetation communities in the upper reaches of the Datong River,and it is a succession in the growth of years.It is recommended that it be popularized and applied in this area.