草业学报2017，Vol.26Issue(9)：14-26,13.DOI:10.11686/cyxb2017005
黄河源区高寒草地植被根—土复合体抗剪强度试验及退化程度阈值确定
Shear strength tests of the root-soil composite system of alpine grassland vegetation at different stages of degradation and the determination of thresholds in the Yellow River source region
摘要
Abstract
The aim of this study was to determine the shear strength of the root-soil composite system from sites with vegetation at different stages of degradation.The selected study area was the alpine grassland in Henan County,Qinghai Province,in the source region of the Yellow River.Shear strength tests were conducted to systematically analyze the characteristics of root-soil composite samples from sites with vegetation at different stages of degradation.The results showed that the grassland in the study area had an irregular ovalshaped pattern of degradation,with more severe degradation close to the center of the oval.From the outside to inside of the irregular oval,the grassland could be divided into a non-degraded (ND) area,a slightly degraded (SD) area,a moderately degraded (MD) area,and a heavily degraded (HD) area.As the degree of degradation increased,the diversity and abundance of local plants decreased,and introduced plants gradually replaced local plants and became dominant.The proportion of roots in soil and the shear strength of the root-soil composite system decreased with increasing degradation.The shear-strength thresholds of the root-soil composite system between neighboring degradation areas were also determined.The threshold of the cohesion of the rootsoil composite system between ND and SD was 28.07 kPa,that between SD and MD was 20.46 kPa,and that between MD and HD was 9.21 kPa.This research to quantify differences in the strength of the root-soil composite system among grasslands with vegetation at different stages of degradation has theoretical value for further scientific studies,and will be useful for developing strategies to prevent and manage grassland degradation.关键词
黄河源区/草地退化/根—土复合体/抗剪强度/阈值Key words
the Yellow River source region/grassland degradation/root-soil composite system/shear strength/threshold引用本文复制引用
刘昌义,胡夏嵩,窦增宁,李希来,徐志闻..黄河源区高寒草地植被根—土复合体抗剪强度试验及退化程度阈值确定[J].草业学报,2017,26(9):14-26,13.基金项目
国家自然科学基金资助项目(41572306,41162010),国家国际科技合作专项项目(2015DFG31870),教育部长江学者和创新团队发展计划(IRT_17R62)和青海省自然科学基金资助项目(2014-ZJ-906)资助. （41572306,41162010）
