谢家店子滑坡体植被恢复与土壤物理性质研究

发布时间：2018-05-26 12:17

本文选题：谢家店子滑坡体 + 植被恢复　；参考：《西华师范大学》2017年硕士论文

【摘要】：2008年汶川地震后,谢家店子发生强烈山体滑坡,滑坡体坡面土壤条件非常恶劣几乎没有植物生长。经过几年自然恢复,滑坡体上植被逐渐丰富,土壤结构等性质逐渐改善。本文以植被恢复过程中植物群落对土壤性质的影响为切入点,对谢家店子滑坡体植被恢复情况、土壤物理性质、以及二者间关系进行研究。建立土壤抗蚀性评价指标体系对滑坡体不同海拔位置土壤抗蚀性评价。主要研究结果如下:(1)2016年谢家店子滑坡体植被恢复良好,各样地均已形成乔灌草的群落结构,植物种类也已经非常丰富。总体上,随着海拔降低,恢复时间增加,群落α多样性的4种指数都处于下降中,表明群落中单一物种聚集现象增强,优势种的地位也在增强。各样地间β多样性Cody指数相较于2012年和2014年显著减小,说明不同海拔样地群落间物种变化速度趋于稳定。总体上滑坡体已经形成桤木lnus cremastogyne-西南绣球Hydrangea davidii+乌泡子Rubu sparkeri-伏地卷柏Selaginella nipponica+边缘鳞盖蕨Microlepia marginata的乔灌草群落。(2)谢家店子滑坡体土壤容重随着海拔降低而逐渐减小。土壤孔隙度、持水性均表现出随海拔降低而增大的趋势,表明相较于坡体上部,坡下下部有更好的通气透水能力,同时保水能力也有明显提升。所有样地土壤均属于轻砾石土,土壤质地还比较密实。随着海拔下降,石砾和砂粒含量有所下降,而粉粒和黏粒含量有所上升,土壤质地密实情况在逐渐改善。所有样地0.25mm团聚体总量均低于50%,土壤结构均较差,但随着海拔降低,总量有所增加,说明土壤结构在改善。团聚体结构破坏率和MWD(干)-MWD(湿)随海拔降低逐渐减小,说明土壤结构稳定性在逐渐增强。随着海拔降低,初渗率、稳渗率、平均渗透率和渗透总量都有所增大。以这四个特性为评价指标做主成份分析,得到土壤渗透性能力评价公式,发现滑坡体表层土壤渗透性随海拔降低而逐渐增强。(3)通过相关性分析得知乔木物种数与灌木物种数、乔木个体总数与灌木个体总数间都表现出负相关。群落多样性中,Margalef指数与其它指数间相关性并不好,而Simpson和Shannon-Weiner之间相关性较好。砂粒含量减少最有助于降低土壤容重。土壤中0.25mm水稳性团聚体相较于0.5mm水稳性团聚体更有利于增强土壤渗透性能。但黏粒含量和总孔隙度大小对土壤渗透影响最大。乔木种类数、个体总数增多有利于改善土壤物理性质。Margalef指数与土壤持水量,土壤渗透等大多数土壤物理性质都表现出负相关性,说明滑坡体上植被丰富度降低反而有利于改善土壤物理性质。(4)选取6类21个指标作为谢家店子土壤抗蚀性评价因子体系,进行土壤抗蚀性评价,结果显示滑坡体土壤抗蚀性主要受土壤渗透性和孔隙度的影响,土壤抗蚀性随海拔降低而逐渐增强,表明随着恢复时间增长,土壤抗蚀性也在增强,原因可能在于土壤中累积了更多的有机质、腐殖质,从而改善了土壤结构。
[Abstract]:After the Wenchuan earthquake in 2008, a strong landslide occurred in the Xie Jia store, and the soil conditions on the slope surface of the landslide body were very bad. After several years of natural recovery, the vegetation on the landslide body was gradually enriched and the soil structure was gradually improved. The restoration of the landslides, the physical properties of the soil and the relationship between the two were studied. The evaluation index system of soil erosion resistance was established to evaluate the soil erosion resistance of the landslides at different altitudes. The main results were as follows: (1) the vegetation of the Xie Jia Zi landslide was well restored in 2016, and the community knot of the grass was formed in all kinds of land. On the whole, with the increase of altitude and the increase of the recovery time, the 4 indices of the community alpha diversity are in the decline, which indicates that the aggregation of single species in the community is increased and the status of the dominant species is enhanced. The number of beta diversity Cody fingers of the community is significantly smaller than that in 2012 and 2014, indicating different seas. The rate of species variation between the plots was stable. On the whole, the landslides had formed the alder lnus cremastogyne- southwestern Hydrangea Hydrangea davidii+, Rubu sparkeri-, Rubu sparkeri-, Rubu sparkeri-, Selaginella nipponica+ edge squid Microlepia marginata. The soil porosity and water holding capacity showed a tendency to increase with the decrease of altitude, which showed that the lower slope was better ventilated and permeable than the upper part of the slope. At the same time, the water retention ability also increased obviously. All soil samples were light gravel soil, and the soil was more dense. With the elevation, gravel and sand grains were reduced. Content decreased, but the content of powder and clay increased, and the density of soil texture was gradually improved. The total amount of 0.25mm aggregate in all samples was less than 50%, the soil structure was poor, but the total amount of soil increased with the decrease of altitude, indicating that soil structure damage rate and MWD (dry) -MWD (wet) decreased gradually with altitude. The stability of soil structure increased gradually. With the decrease of altitude, the initial permeability, the permeability, the average permeability and the total permeation were all increased. The evaluation formula of the four characteristics was used as the evaluation index, and the evaluation formula of soil permeability ability was obtained. It was found that the permeability of the surface soil of the landslide body was gradually increased with the decrease of altitude. (3) The correlation analysis showed that the number of tree species and the number of shrubs showed negative correlation between the total number of trees and the total number of shrubs. Among the community diversity, the correlation between the Margalef index and the other indices was not good, but the correlation between Simpson and Shannon-Weiner was better. 0.25mm water stable aggregates are more beneficial to soil permeability than 0.5mm water stable aggregates. However, the number of clay particles and total porosity have the greatest impact on soil permeability. The number of trees and the increase of the number of individuals are beneficial to the improvement of soil physical properties.Margalef index and soil water holding capacity, soil permeability and so on. The properties all show negative correlation, indicating that the decrease of vegetation richness on the landslide is beneficial to improving the physical properties of soil. (4) select 6 categories and 21 indexes as the evaluation factor system of the soil anti erodibility of the Shijia store, and evaluate the soil erosion resistance. The results show that the soil erosion resistance of the landslide is mainly influenced by soil permeability and porosity, and the soil erosion resistance is mainly influenced by soil permeability and porosity. The erosion resistance of soil gradually increased with the decrease of altitude, indicating that the soil corrosion resistance was also enhanced with the increase of recovery time, which may be due to the accumulation of more organic matter and humus in the soil, thus improving the soil structure.
【学位授予单位】：西华师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157

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