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

发布时间：2018-04-29 12:34

本文选题：黄河源区 + 草地退化　；参考：《草业学报》2017年09期

【摘要】：为研究黄河源区高寒草地不同退化程度的植物根-土复合体抗剪强度特征,以青海河南县境内的黄河源区高寒草地作为研究区,进行了根-土复合体试样抗剪强度试验研究,系统分析了区内草地不同退化类型的根-土复合体抗剪强度特征及其不同退化程度之间的阈值。结果表明,区内草地其平面形态呈现不规则状椭圆形退化形态,且愈近于圆心部位草地退化相对愈严重,其退化程度表现出由外至内可依次划分为未退化区、轻度退化区、中度退化区、重度退化区;随着退化程度的加剧,原生植物种类及数量呈减少的趋势,次生植物则逐渐取代原生植物并构成优势植物种类,其结果使得根-土复合体的根系含量表现出逐渐减少的特征,根-土复合体抗剪强度亦逐渐减小;同时,根据4种类型退化区草地根-土复合体抗剪强度特征,分别确定出各退化区交替界限之间的根-土复合体抗剪强度阈值,即表现在未退化区与轻度退化区之间植物根-土复合体的黏聚力阈值为28.07kPa,轻度退化区与中度退化区复合体的黏聚力阈值为20.46kPa,中度退化区与重度退化区复合体的黏聚力阈值为9.21kPa。该项研究成果通过由力学强度角度出发定量研究草地不同退化程度的根-土复合体强度变化规律,从而对科学有效地防治该区草地退化具有重要理论研究价值和实际指导意义。
[Abstract]:In order to study the shear strength characteristics of plant root-soil complex with different degrees of degradation in the alpine grassland in the source region of the Yellow River, the shear strength of the root soil complex sample was studied with the alpine grassland in the source region of the Yellow River in Henan, Qinghai Province, as the study area. The shear strength characteristics of root-soil complexes of different degraded types of grassland in this area and the thresholds between different degradation degrees were analyzed systematically. The results showed that the planar morphology of grassland in the region presented irregular elliptical degeneration, and the degradation degree of the grassland near the center of the grassland was relatively more serious. The degradation degree of the grassland could be divided into undegraded area and mild degraded area from outside to inside. With the increase of degradation degree, the species and quantity of native plants decreased, while secondary plants gradually replaced native plants and constituted dominant plant species. The results show that the root content of root-soil complex decreases gradually, and the shear strength of root-soil complex decreases gradually, and the shear strength of root-soil complex in four types of degraded grassland is analyzed. The shear strength threshold of root-soil complex between the alternating boundaries of each degraded area is determined respectively. The cohesion threshold of plant root-soil complex is 28.07 KPA, the cohesion threshold of mild degraded zone and moderate degraded area is 20.46 KPA, the cohesion threshold of moderate degraded zone and severe degraded area complex is 9.21 kPa. From the point of view of mechanical strength, the results of this study quantitatively study the change law of root-soil complex strength in different degree of grassland degradation, which has important theoretical research value and practical guiding significance for scientific and effective prevention and control of grassland degradation in this area.
【作者单位】：青海大学地质工程系;中国科学院青海盐湖研究所;青海大学农牧学院;
【基金】：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) 青海省自然科学基金资助项目(2014-ZJ-906)资助
【分类号】：S812.6

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