Effects of four different grazing exclusion conditions on the mechanical characteristics of grassland root-soil composite system in the source region of the Yellow River
[Objective]The aims of this study are to explore the impact of the ban on grazing in the high-altitude and cold environment of the Yellow River source region on the mechanical strength of the root-soil composite system in native grasslands and degraded grasslands,to clarify the role of the ban on vegetation restoration,and to provide theoretical reference for the restoration of grasslands in the Yellow River source region and geological disaster prevention and control.[Methods]The grassland in Henan County of the Yellow River source region was selected as the research object under four conditions of no grazing,1-year,4-year and 10-year of grazing prohibition period.The correlation between root diameter,soil density,soil moisture content,root content and root-soil composite system cohesion of grassland plants in different grazing prohibition periods was discussed.[Results](1)There was a significant negative correlation between cohesion and water content of root-soil composite system(p<0.05).There was a significant positive correlation between root diameter and cohesion of root-soil composite system(R=0.68,p<0.01).There was a significant positive correlation between root number and cohesion of root-soil composite system(R=0.85,p<0.01).There was a positive correlation between soil density and cohesion c value of root-soil composite system during 1-year grazing exclusion period(R=0.56,p<0.05).(2)With the increase of grazing prohibition years,the average cohesion c value of native and degraded grassland soil increased,and the cohesion c value of native grassland in 10-year grazing prohibition period increased by 6.39%compared with the average cohesion of native grassland without grazing prohibition.The cohesion c value of degraded grassland during the 10-year grazing exclusion period increased by 8.16%compared with the average cohesion of non-grazing.[Conclusion]The implementation of grazing prohibition to improve the cohesion of grassland root-soil composite system in the source region of the Yellow River is conducive to the prevention and control of grassland degradation and soil erosion in the source region of the Yellow River.
the source region of the Yellow Riverroot-soil composite systemgrazing ban periodnative grasslanddegraded grasslandshear strength index