Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： For this study of the physical and chemical properties and mechanical characteristics of soil in the distribution area of Xiazangtan super large scale landslide of the upper Yellow River, plants and soil samples at different positions of the landslide were collected, and the plant growth index, soil density, water content, root content, shear strength index, and nutrient element content were measured. Spearman’s correlation analysis was used to explore the vegetation types, physical and chemical properties of soil, and the shear strength characteristics of the root–soil composite system in different positions of the landslide. The number of plant species tended to increase as the altitude decreased, and the dominant herbaceous herbs were Stipa aliena, Oxytropis ochrocephala, and Artemisia desertorum. The pH of the soil in the distribution area of the landslide was neutral to alkaline. The contents of organic matter, total nitrogen, and total phosphorus change greatly at the trailing edge of the landslide, whereas the contents of total potassium, alkali-hydrolyzed nitrogen, and four other nutrients change greatly but do not show obvious variation. The water content of soil first increases and then decreases with the decrease in altitude, while the density of soil increases as the altitude decreases, increasing by 7.05% and 5.88%, respectively. The cohesion c value and root content of the root-soil composite system first increased and then decreased as the altitude decreased. In addition, Spearman correlation analysis showed that the cohesion c value of the root-soil composite system was negatively correlated with altitude, but positively correlated with root content, organic matter, and water content. The results of this study have practical significance for guiding the prevention and control of geological disasters such as soil erosion, and shallow landslide in the upper reaches of the Yellow River, from Longyang Gorge to Jishi Gorge.
Subjects: Geosciences >> Geography submitted time 2023-04-07 Cooperative journals: 《干旱区地理》
Abstract： Soil wind erosion is the primary stage and important component of desertification in arid and semiarid regions. Evaluating its possibility and potential risk for wind erosion control at the regional level is of considerable importance. In recent years, remote sensing and geographic information technology are often combined with mathematical methods to build a risk assessment model. However, the current risk models of wind erosion are still lacking in mechanical parameters. This study was conducted in the Hetao Plain of China, which is a typical region of wind erosion and desertification. Soil hardness and shear strength were measured in the field to determine the difference in soil erodibility among different land use types. Wind erosion risk was evaluated using fuzzy logic, analytic hierarchy process, and the weighted linear combination method based on the data of climate conditions, soil physical factors, topography, and vegetation characteristics. Then, the spatial distribution characteristics and causes of different risk areas were analyzed. The following results are presented. (1) The shear strength of land use types shows an increased tendency in the order of sandy land, grassland, woodland, cultivated land, and saline land, which agreed well with the soil hardness. The soil hardness and shear strength of sandy land are 2.05 kg·cm−2 and 10.00 kPa, respectively, which are significantly lower than those of other land use types, indicating that the soil erodibility of sandy land is extremely high. (2) The wind erosion risk varied in spatial distribution. Wind erosion hazard is high in the west and south and low in the eastern and middle regions. Moreover, 27.51% of the total areas are found to be at a high risk of erosion. Thus, soil erodibility and vegetation coverage are essential factors affecting soil wind erosion. (3) The severe risk region is mainly distributed in most of Dengkou County, the edge of the south bank of the Yellow River, Togtoh County, and the east of Wuliangsuhai in the Urad Front Banner. Therefore, this area should be the focus of wind erosion control. The current research demonstrates strong universality and compensates for the shortcomings of existing wind erosion models, which can provide a theoretical basis for regional-scale wind erosion assessment models.
Subjects: Geosciences >> Geography submitted time 2021-04-23 Cooperative journals: 《干旱区研究》
Abstract：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d60参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。
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：以青藏铁路沱沱河段取土场作为研究区，选取生长年限为10 a的碱茅[Puccinellia distans (Linn.) Parl.]、垂穗披碱草（Elymus nutans Griseb.）、冷地早熟禾（Poa crymophila L.）和星星草[Puccinellia tenuiflora (Griseb.) Scribn.] 4种草本作为试验供试种，分别进行室内单根拉伸与剪切试验，较为系统地评价了4种草本其单根力学强度特征。结果表明：（1）取土场4种草本单根平均抗拉强度由大至小为：碱茅（66.29 MPa）>垂穗披碱草（50.78 MPa）>冷地早熟禾（46.11 MPa）>星星草（40.62 MPa），单根平均抗剪强度由大至小为：碱茅（44.37 MPa）>垂穗披碱草（37.74 MPa）>冷地早熟禾（36.80 MPa）>星星草（26.66 MPa），且两者均与根径之间符合幂函数负相关关系；（2）对生长年限为5 a和10 a的4种草本单根抗拉力和抗剪力对比分析得出，4种草本根系抗拉力增长幅度为11.71%~62.31%，抗剪力增长幅度为26.30%~92.61%；（3）比较4种草本根系其不同根径级别的力学强度，得出碱茅和垂穗披碱草根系力学性能相对优于其他2种草本，可优先作为研究区固土护坡植物种。本研究可为青藏铁路沱沱河段及周边优势护坡植物的筛选提供一定理论依据。
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