汶川大地震对四川理县岷江柏林土壤理化性质及微生物多样性的影响

发布时间：2018-06-16 23:35

本文选题：汶川地震 + 四川理县　；参考：《中国林业科学研究院》2015年硕士论文

【摘要】：2008年发生的“5.12”汶川大地震发生地是我国长江上游重要的水源涵养地和水土保持区,也是我国森林资源的主要分布区之一。地震造成的水土流失、山体滑坡、泥石流等次生灾害,对森林生态系统的稳定和发展带来了持续的不利影响,造成土层变薄、土壤贫瘠化,森林生态功能下降。为此,通过对灾区森林土壤环境的变化特征的研究,对加快灾区森林土壤的生态修复,确保该区域的生态安全具有十分重要意义。本文以理县的熊尔山和蒲溪沟两个受灾区中典型的人工林岷江柏林作为研究对象,采用现代仪器分析方法和分子生物学技术,围绕土壤的基本理化性质、土壤微生物丰度和土壤粘粒矿物等方面开展比较研究,探索地震对森林土壤环境质量带来的影响,为灾区土壤修复提供可靠的理论依据。研究结果得到:(1)地震对岷江柏林土壤理化性质带来十分明显的变化。与未遭地震破坏的土壤相比,5个受地震影响严重的林分表层土壤(0~20 cm)的粘粒含量平均下降了54.4%,土壤容重平均值达1.28 g·cm-3,显著高于对照土壤。同时,地震后造成各个土层(0~20cm、20~40 cm和40~60 cm)的p H显著升高,p H值平均提高了11.5%。地震造成的土体挤压和山体崩塌在一定程度上导致了土壤容重升高,总孔隙度降低,地震造成土壤团聚结构体破坏,土壤颗粒缺乏有机质的胶结,进而土壤抗侵蚀能力减弱,发生粘粒淋失。。受地震影响土壤的阳离子交换量(CEC)最大值为5.88 cmol·kg-1,最小值为1.74cmol·kg-1,平均值为3.72 cmol·kg-1,是对照土壤的1/4~1/5,土壤保肥能力十分低下。土壤粘粒流失、有机质含量减少及p H值增加是导致CEC减少的主要原因。受地震影响土壤的全氮、碱解氮、有效磷、速效钾平均含量均低于对照区,土壤有机质与全氮、碱解氮、有效磷、阳离子交换量之间的相关性达到显著,说明土壤的有机质含量对土壤肥力的提高和维持具有十分重要的作用。调查地的土壤C/N大部分在12以下,而对照土壤的值在19.5~34.9的范围内,表明地震造成土壤的碳损失率大于氮损失率。(2)地震对土壤微生物的群落结构和丰度带来显著的影响。运用荧光定量PCR技术对地震灾区六种土壤微生物丰度进行对比分析得到,调查区土壤中除了含细菌、真菌外,古菌含量也较高。受地震影响,土壤的细菌、真菌、古菌、泉古菌、氨氧化古菌和氨氧化细菌的基因拷贝数平均值分别为4.73×107 copies·g-1干土,6.89×105 copies·g-1干土,2.88×106 copies·g-1干土,6.25×105 copies·g-1干土,5.36×104 copies·g-1干土和4.77×104 copies·g-1干土,都出现显著的下降。受地震影响土壤的不同微生物的平均基因拷贝数由大到小排序为细菌古菌真菌泉古菌氨氧化古菌氨氧化细菌。细菌具有较高的丰度,是受灾地土壤微生物群落中的优势菌。地震影响土壤的微生物数量与土壤各项理化性质相关性不显著。主成分分析发现,古菌、泉古菌和氨氧化古菌3类菌群之间关系密切,表明氨氧化古菌在泉古菌或固菌中占有重要的位置。同时发现,氨氧化古菌和同氨氧化细菌在研究土壤中的数量变动存在着明显的不一致性,两者之间存在着互补性。细菌和真菌在主成分分析中占有位置十分相近,可能同两类微生物同土壤有机质的紧密关系有关,地震造成土壤有机质的急剧减少,将严重影响土壤细菌和真菌的数量。(3)土壤粘粒对调查土壤的理化特性、肥力保持等方面都具有重要的意义。采用XRD、红外谱和EDS等技术分析得到,调查熊尔山、蒲溪沟两地土壤的粘粒组成相似,主要是伊利石、高岭石、绿泥石和伊蒙混层,其中伊利石含量高达69.8%~77.7%。化学组成均以Si O2、A12O3、Fe2O3为主,其中Si O2含量占到一半左右。土壤粘粒比表面积在56.8~46.5 m3·g-1,均以介孔为主。调查土壤中粘粒的组成和结构特征对土壤保水、保肥具有十分重要的作用。研究表明,地震带来的土壤障碍因子包括:土壤有机质含量减少,土壤p H升高,表层土壤质地较粗,粘粒含量少,土壤微生物多样性减少。为此,我们提出以下土壤修复建议:(1)增加土壤有机质。可根据当地实际情况建议施用有机肥料或套种绿肥。(2)提高土壤粘土矿物含量。适当添加缓冲性能强的粘土矿物如蒙脱石、蛭石等,有助于丰富土壤粘粒的组成成分和提高粘粒含量,提高土壤阳离子交换量,促进土壤有机无机复合体的形成。(3)改善土壤p H值。可以选择施用一定的酸性肥料有机无机复合肥(如农家肥和硫酸铵复合肥)、酸性有机改良剂(如褐煤、风化煤等)及p H值相对较低的低温生物炭等修复材料,达到既改善土壤p H条件,又提高土壤有机质的效果。
[Abstract]:The "5.12" Wenchuan earthquake occurred in 2008 is an important source of water conservation and soil conservation areas in the upper reaches of the Yangtze River, and one of the main distribution areas of forest resources in China. The secondary disasters such as soil erosion, landslides and debris flows caused by the earthquake have brought a continuous negative impact on the stability and development of the forest ecological system. The soil layer becomes thinner, the soil is barren and the ecological function of the forest is reduced. Therefore, it is of great significance to accelerate the ecological restoration of the forest soil and ensure the ecological security of the area by the study of the change characteristics of the forest soil environment in the disaster area. This paper takes the two typical artificial forests in Xiong and Puxi gully of Lixian. Berlin, Minjiang River, as a research object, uses modern instrumental analysis and molecular biology techniques to compare the basic physical and chemical properties of soil, soil microbial abundance and soil clay minerals, explore the impact of earthquake on the quality of forest soil environment, and provide a reliable theoretical basis for soil remediation in disaster areas. The results are as follows: (1) the physical and chemical properties of the soil in Berlin, Minjiang River, have been greatly changed. Compared with the soil without earthquake damage, the content of the clay particles in the soil surface soil (0~20 cm), which is seriously affected by the earthquake, decreased by 54.4% and the average value of the soil bulk density reached 1.28 G. Cm-3, which was significantly higher than that of the control soil. The P H of each soil layer (0~20cm, 20~40 cm and 40~60 cm) increased significantly. The P H value increased the soil bulk density and the mountain collapse caused by the 11.5%. earthquake to a certain extent, which resulted in the increase of soil bulk density, the decrease of total porosity, the destruction of the soil aggregate structure, the lack of cementation of the organic matter in the soil particles, and the erosion resistance of the soil. The maximum value of CEC is 5.88 CMoL. Kg-1, the minimum value is 1.74cmol. Kg-1, and the average value is 3.72 CMoL. Kg-1. It is the 1/4~1/5 of the soil, and the soil conservation ability is very low. The loss of soil clay particles, the decrease of organic matter and the increase of P H value are the main factors that lead to the CEC decrease. The average content of total nitrogen, alkali hydrolysable nitrogen, available phosphorus and available potassium in soil was lower than that of the control area. The correlation between soil organic matter and total nitrogen, alkali hydrolysable nitrogen, available phosphorus and cation exchange was significant, indicating that soil organic matter content was very important to the improvement and maintenance of soil fertility. The soil C The majority of /N is below 12, while the value of soil in the range of 19.5~34.9 indicates that the soil carbon loss rate is greater than the nitrogen loss rate. (2) the earthquake has a significant influence on the community structure and abundance of soil microbes. The fluorescence quantitative PCR technique is used to compare and analyze the abundance of six kinds of soil microbes in the earthquake stricken areas. Besides bacteria and fungi, the content of palaeophore in the soil was also high. The average value of gene copies of bacteria, fungi, archaea, spring palaebacteria, ammoxic and ammoxidation bacteria was 4.73 * 107 copies. G-1 dry soil, 6.89 x 105 copies / g-1 dry soil, 2.88 x 106 copies. G-1 dry soil, 6.25 * 105 copies g-1 dry soil. The 5.36 * 104 copies / g-1 dry soil and 4.77 x 104 copies / g-1 dry soil were all significantly decreased. The average gene copy number of different microbes from the soil affected by the earthquake was from large to small to the bacteria paleo ammoxidation of paleo ammoxic bacteria. The bacteria had higher abundance, which was the advantage of the soil microbial community in the affected soil. The correlation between the number of microbes affecting the soil and the physical and chemical properties of soil was not significant. The principal component analysis found that the relationship between the 3 types of bacteria was closely related to the Archaea, the paleoarchaea and the ammoxic bacteria, indicating that the ammonia oxidizing archaea had an important position in the spring palaeobacteria or the solid bacteria. There are obvious inconsistencies in the changes in the number of soil. The position of the bacteria and fungi in the principal component analysis is very close, which may be related to the close relationship between the two types of microbes and the organic matter in the soil. The earthquake caused a sharp decrease in the organic matter of the soil, which will seriously affect the number of soil bacteria and fungi. (3) Soil clay particles are of great significance to the investigation of soil physical and chemical properties and fertility. Using XRD, infrared spectrum and EDS techniques, the clay particles in the soils of Xiong mountain and Puxi gully are similar, mainly illite, kaolinite, chlorite and Imime, and the illite content is up to the 69.8%~77.7%. chemical group. The content of Si O2, A12O3 and Fe2O3 dominated, of which the content of Si O2 accounted for about half. The specific surface area of soil clay particles was 56.8~46.5 m3. G-1, which were mainly mesoporous. The investigation of the composition and structural characteristics of clay particles in soil has a very important role in soil conservation and fertilizer conservation. The soil P H increased, soil texture was coarser, clay content was less, and soil microbial diversity decreased. Therefore, we proposed the following soil remediation recommendations: (1) increase soil organic matter. Organic manure or interplanting green manure can be applied according to local actual conditions. (2) improve soil clay mineral content. Appropriate adding buffer performance is strong. Clay minerals such as montmorillonite and vermiculite help to enrich the composition of soil clay particles and increase the content of clay particles, increase the amount of soil cation exchange and promote the formation of soil organic and inorganic complexes. (3) improving the P H value of soil. Organic modifiers (such as lignite, weathered coal, etc.) and low P H values of low temperature biological carbon have been used to improve the soil P H conditions and improve the effect of soil organic matter.
【学位授予单位】：中国林业科学研究院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714

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