黄河源区高寒草地不同深度土壤理化性质与抗剪强度关系研究

Relationships between the physical and chemical properties of soil and the shear strength of root-soil composite systems at different soil depths in alpine grassland in the source region of the Yellow River

以黄河源区的高寒草地为研究对象,探讨了草地和裸地在0~10 cm、10~20 cm、20~30 cm、30~40 cm和40~50 cm 5种不同深度土壤理化性质和根-土复合体抗剪强度特征。研究结果表明:黄河源区的土壤为弱碱性土,且pH值、密度随着土壤深度增加而增大。土壤含水率、有机质随土壤深度的增加表现出减小的变化趋势。与此同时,草地土体粘聚力c值随深度增加而降低,而裸地则表现出随土壤深度的增加而增大的变化特征。由灰色关联法分析结果表明:草地根-土复合体粘聚力c值与速效磷、含根量和有机质的关联度相对较高,分别为0.82、0.82、0.76,裸地土体粘聚力c值则与密度、pH值和土壤颗粒控制粒径d_(60)参数值的关联度相对较高,即分别为0.76、0.74、0.73。研究结果对科学有效防治高寒区因草地退化引起的水土流失、浅层滑坡等灾害现象的发生,具有理论研究价值和现实意义。

The relationships between the physical and chemical properties of soil,the shear strength of the rootsoil composite system,and the soil depth were investigated in the alpine grassland in Henan Country,Qinghai Province,in the source region of the Yellow River.Direct shear tests of root-soil composite systems and soil physical and chemical content tests were conducted.Five different soil depths(0-10 cm,10-20 cm,20-30 cm,30-40 cm,and 40-50 cm)were selected for sampling.The results showed that the soil moisture content decreased gradually with increasing soil depth.The soil was weakly alkaline,and the soil pH increased.The content of organic matter and nutrient elements in the soil decreased with increasing soil depth.Additionally,the cohesion c value of the soil in the non-degraded grassland gradually decreased with increasing soil depth.For the degraded bare land,the cohesion c value of the soil gradually increased with increasing soil depth.According to the analysis of the gray relational method,the shear strength of the root-soil composite systems was closely related to available P(0.82),root content(0.82),and organic matter(0.76).Additionally,the shear strength was correlated with density of bare soil(0.76)and soil particle size d_(60)(0.74).The results of this study can be used to inform the effective prevention and control of soil erosion,shallow landslide,and other disasters caused by grassland degradation in extremely cold areas.