土壤中不同形态水的化学组成研究

发布时间：2018-06-10 06:37

本文选题：土壤质地 + 重力水　；参考：《南京大学》2015年硕士论文

【摘要】：土壤水是土壤的重要组成部分之一,土壤中各种物质的运移,主要是以水溶液的形式进行的。土壤水与大气降水、地表水、地下水以及植被都有着重要的联系,在水分循环和物质循环中发挥着至关重要的作用。研究表明,土壤中不同形态水分对植物生长和地下水的贡献不同。因此,研究土壤中不同形态水的化学组成,对于植物生长、土壤-地下水之间污染物运移具有重要的指导意义。本文以南京八卦洲地区3种典型土壤及中山弱透水层土壤为研究对象,利用室内分步离心的方法,提取自然状态下4种质地土壤中的重力水、毛管水和有效膜状水,研究土壤中不同形态水的水分含量和化学组分分布特征,结合土壤的理化性质,探讨影响各形态水水化学成分的因素。得出的主要结论有:1、中山与八卦洲4种质地土壤中各形态水的水分含量变化特征一致,表现为毛管水有效膜状水重力水,但各形态水分含量占土壤总含水量的比例因采样点不同而变化。中山轻粘土采自地下水面以下,其重力水占土壤总含水量的比例明显高于八卦洲3种质地土壤。八卦洲3种质地土壤成土背景相似,粘粒含量是影响各形态水分含量的重要因素,土壤中自由水(重力水+毛管水)占土壤总含水量的比例随土壤粘粒含量增加而降低。2、中山和八卦洲4种质地土壤的各形态水中Zn、Cu、Ni和Cr含量变化特征相似,都表现为毛管水中各重金属含量最低。土壤各形态水中重金属呈不均匀分布,由各形态水分在土壤中赋存条件、滞留时间及化学过程不同所决定。毛管水受毛管力作用保持于毛管孔隙中,不易存留质量分数较大的重金属元素,导致其重金属含量较低。重力水在土壤中迁移性最强,容易受到降水对表层淋滤、灌溉等外源输入因素的影响。有效膜状水中重金属含量受土壤中重金属的释放作用明显。土壤本身重金属含量和成土背景制约着各形态水中重金属含量基准值。八卦洲采样地由长江冲积形成,其土壤各形态水中重金属含量基准值受土壤本身重金属含量的制约。中山土壤采样地曾经历过海水入侵,海水长期与土壤接触,通过物理、化学及生物过程影响土壤中重金属的释放,进而对各形态水中重金属含量产生影响。中山轻粘土各形态水中As、Zn、V和Cu的含量至少比八卦洲各形态水中元素含量高一个数量级。八卦洲3种土壤成土环境及矿物组成相似,其重力水与毛管水之间的重金属含量差异性随土壤中粘粒含量增加而变大,说明粘粒含量对重金属在重力水-毛管水之间的迁移转化具有控制作用。粘粒含量越低,越有利于重力水与毛管水之间的重金属交换。而土壤有效膜状水与毛管水之间的重金属交换作用受土壤粘粒含量和有机质含量共同作用。3、土壤各形态水中主量元素含量分布特征不一致。其中八卦洲3种质地土壤的重力水、毛管水和有效膜状水中各主量元素含量无明显差异。中山土壤的有效膜状水和毛管水中主量元素含量差别不大,高于重力水中各元素含量。中山土壤长期处于与海水接触的环境中,Na+是各形态水中主要阳离子。八卦洲3种土壤各形态水中主量元素来源于碳酸盐等矿物的溶解,Ca~(2+)为主要阳离子。受海水入侵的影响,中山轻粘土土壤水中Ca、Na、Mg和K的含量显著高于八卦洲3种质地土壤水中各元素浓度。八卦洲3种质地土壤的成土环境及矿物组成相似,土壤粘粒含量是影响各形态水中主量元素的主要因素,砂壤土各形态水中Ca、Mg和Na的含量最高。
[Abstract]:Soil water is one of the important components of soil. The movement of various substances in the soil is mainly carried out in the form of aqueous solution. Soil water has an important relationship with atmospheric precipitation, surface water, ground water and vegetation, and plays an important role in the water cycle and material circulation. The contribution of the division to the plant growth and the groundwater is different. Therefore, the study of the chemical composition of different forms of water in the soil has important guiding significance for the plant growth and the movement of the pollutants between the soil and the groundwater. In this paper, 3 typical soils and the weak pervious layer soil in Zhongshan, Bagua, Nanjing, are taken as the research object, and the indoor stepwise centrifugation is used. Methods, the gravity water, capillary water and effective membrane water in the soil of 4 natural states were extracted. The water content and chemical composition distribution characteristics of different forms of water in the soil were studied, and the factors affecting the chemical composition of water and water in various forms were discussed in combination with the physical and chemical properties of the soil. The main conclusions were as follows: 1, 4 soil soils in Zhongshan and Bagua continent were found. The water content of the water in each form is the same, showing the effective membrane water gravitational water of the capillary water, but the proportion of the water content of each form varies with the sampling point. The proportion of the light clay in Zhongshan is below the surface of the ground, and the proportion of its gravity water to the total soil water content is obviously higher than that of the 3 germplasm soil in Bagua continent. Eight The soil formation background of the 3 germplasm of Gua Zhou is similar, and the content of clay particles is an important factor affecting the water content of each form. The proportion of free water (gravity water + capillary water) in soil decreases.2 with the increase of soil clay content, and the changes of Zn, Cu, Ni and Cr in various forms of soil in Zhongshan and Bagua Zhou 4 germplasm are similar. The heavy metals in the water are the lowest in the water. The heavy metals in each form of the soil are unevenly distributed, which are determined by the conditions of each form of water in the soil, the retention time and the chemical process are different. The capillary force of the capillary water is kept in the pore of the capillary, and it is not easy to retain the heavy metal elements which have large mass fraction, causing its heavy weight. The content of heavy metals in the effective membrane water is obviously affected by the release of heavy metals in the soil. The heavy metal content and the background of the soil itself restrict the reference value of the heavy metal content in the water. Eight The sampling site of hexagram is formed by the alluvium of the Yangtze River. The reference value of heavy metals in each form of the soil is restricted by the content of the heavy metal in the soil itself. The soil sampling site in Zhongshan has experienced the invasion of the sea water, the sea water is exposed to the soil for a long time, and the physical, chemical and biological processes affect the release of heavy metals in the soil and then the heavy gold in the water. The content of As, Zn, V and Cu in the water of Zhongshan light clay is at least one order of order higher than that of the water elements in the eight diagrams. The soil formation environment and mineral composition of the eight diagrams are similar. The difference of the heavy metal content between the gravity water and the capillary water increases with the increase of the clay content in the soil, indicating the clay particles. The content of heavy metals has a control effect on the transfer and transformation between the gravity water and the capillary water. The lower the content of the clay particles, the more conducive to the exchange of heavy metals between the gravity water and the capillary water. The exchange of heavy metals between the soil effective membrane water and the capillary water is affected by the soil clay content and the organic matter content,.3, and the water in each form of the soil. There is no significant difference in the content distribution of main elements. There is no significant difference in the content of the main elements in the soil of the 3 germplasm of the Eight Diagrams continent, in the water and in the effective membrane water. The content of the effective membrane water and the main element content in the water of the Zhongshan soil is not very different, which is higher than the content of the elements in the gravity water. The soil of Zhongshan has long been connected with the sea water. In the contact environment, Na+ is the main cation in various forms of water. The main elements of the 3 kinds of soil in the eight diagrams of the eight diagrams of soil are derived from the dissolution of carbonate and other minerals, and Ca~ (2+) is the main cation. Under the influence of seawater intrusion, the content of Ca, Na, Mg and K in the water of Zhongshan light clay soil is significantly higher than the concentration of each element in the soil water of the eight guugua 3 germplasm. Eight The soil forming environment and mineral composition of the 3 germplasm of Gua Zhou are similar. The content of soil clay particles is the main factor affecting the main elements in the water, and the content of Ca, Mg and Na in the water of sandy loam is the highest.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S151.9

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