河西绿洲灌区土壤盐渍化特征及其与有效锌含量关系研究

发布时间：2018-03-08 19:15

本文选题：有效锌　切入点：全盐　出处：《甘肃农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以河西绿洲灌区盐渍化耕地土壤为研究对象,对土壤的盐渍化特征及其与土壤有效锌含量的关系进行了调查研究,为揭示河西绿洲灌区盐渍化环境对土壤有效锌影响机理提供了可靠的参考。通过对研究区内农田的盐渍化环境因子含量及有效锌含量的测定,对盐渍化环境因子(盐分含量、p H值、盐分离子组成)与有效锌间的相关关系进行统计分析,得出如下结论。(1)研究区各层土壤均呈盐化状态,剖面土壤盐分具有明显的表聚特征,呈“T”型分布。剖面中的阳离子以Ca2+为主,离子含量最高,占各土层阳离子总量的31.28%~48.09%,其次是Na+,占25.11%~35.18%;阴离子以SO42-为主,占各土层阴离子总量的70%以上,其次是HCO3-,占7.60%~20.00%。各层土壤p H的平均值介于8.55~8.63之间。(2)研究区土壤中的有效锌含量介于0.289~0.736mg.kg-1之间,平均为0.473mg.kg-1,低于土壤缺锌临界值(0.5 mg.kg-1),变异系数为18.67%。该区盐渍化土壤的有效锌含量总体较低。从不同类型盐碱地土壤有效锌的含量来看,盐化潮土最高,黑碱土次之,镁质盐渍土最低;从不同盐渍化程度土壤有效锌含量来看,轻质盐渍土最高,中度盐渍土次之,重度盐渍土最低。(3)典范对应分析结果表明,K+与Mg2+、Ca2+与SO42-在各土层内始终有较好的关联性;Na+与Cl-在0~20cm和40~100cm土层的关联性较好,SO42-与Na+正好与其相反,在20~40cm土层的关联性较好;K+与Na+在40~80cm土层的关联性较好。在0~100 cm全剖面上,土壤p H的空间分布受HCO3-和Na+含量的影响较大,土壤含盐量受SO42-、Cl-和Ca2+含量的影响较大,是影响河西绿洲灌区盐碱地类型和分布的主要因素。(4)各土层的影响因素与全剖面有所不同,0~20 cm土层内土壤含盐量和p H的空间分布主要受控于SO42-含量,20~40 cm土层内受Cl-、Na+-、Ca2+和SO42-共同影响,40~60cm和60~80cm土层内K+是主要影响因素,80~100 cm土层内主要受控于K+和Mg2+含量。(5)该区盐渍化土壤的有效锌含量总体较低。从不同类型盐碱地土壤有效锌的含量来看,盐化潮土最高,黑碱土次之,镁质盐渍土最低;从不同盐渍化程度土壤有效锌含量来看,轻质盐渍土最高,中度盐渍土次之,重度盐渍土最低。(6)全盐含量的高低不是影响土壤有效锌含量的决定因素。p H值与有效锌含量之间呈现出了极显著的负相关关系,但是负相关关系的变异性较大。盐分离子中HCO3-和Mg2+与有效锌含量呈现出了极显著的负相关关系;其他离子在回归分析过程中拟合程度并不好,没有较显著的相关关系。
[Abstract]:In this paper, the salinization characteristics of soil and the relationship between soil salinization and available zinc content in Hexi oasis irrigated area were investigated. In order to reveal the influence mechanism of salinized environment on soil available zinc in Hexi oasis irrigation area, the contents of salinized environmental factors and available zinc in farmland were determined. The correlation between salinization environmental factors (salt content, pH value, salt ion composition) and available zinc was statistically analyzed. In the profile, Ca2 is the main cations, and the ion content is the highest, accounting for 31.288.09% of the total cations in each soil layer, followed by Na (25.11% 35.18%), and so 42- is the main anion in the profile. Accounting for more than 70% of the total anions in each soil layer, followed by HCO _ 3, which accounted for 7.60,20.00.The average value of soil pH in each layer was between 8.55 and 8.63, and the available zinc content in the soil was between 0.289 and 0.736 mg 路kg ~ (-1). The average value was 0.473 mg 路kg ~ (-1), which was lower than the critical value of soil zinc deficiency (0.5 mg 路kg ~ (-1)), and the coefficient of variation was 18.67. The available zinc content of salinized soil in this area was relatively low. According to the content of available zinc in different types of saline-alkali soil, salinized tidal soil was the highest, and black alkali soil was the second. According to the soil available zinc content of different salinization degree, the light saline soil is the highest, the moderate salinized soil is the second. The results of canonical correspondence analysis showed that the correlation between K and Mg2 Ca 2 and so 42- was always good in each soil layer. The correlation between Na and Cl- was better in 0 ~ 20 cm and 40 ~ 100 cm soil layer, so _ 42- and Na were just the opposite. The correlation between K and Na was better in the soil layer of 20 ~ 40cm than that in the soil layer of 40 ~ 80cm. The spatial distribution of soil pH was greatly affected by the contents of HCO3- and Na, and the salinity of soil was influenced by the contents of SO42-Cl- and Ca2. It is the main factor that affects the type and distribution of saline-alkali land in Hexi oasis irrigation area.) the influencing factors and the whole profile of each soil layer are different. The spatial distribution of soil salinity and pH in 20cm soil layer is mainly controlled by so _ 4 _ 2-content ~ (20) ~ (40 cm) soil layer. K in the soil layer of 40cm and 80cm is the main factor controlled by K and Mg2 contents in 100cm soil layer.) the available zinc content of salinized soil in this area is generally lower. The available zinc content of soil in different types of saline and alkali soils is lower than that in the soil layer of different types of saline-alkali soil. The salinized tidal soil was the highest, the black alkali soil was the second, the magnesia saline soil was the lowest, and the light salinized soil was the highest, the moderate saline soil was the second, according to the soil available zinc content of different salinization degree, There was a significant negative correlation between total salt content and available zinc content, which was not the determinant factor of soil available zinc content. However, there was a significant negative correlation between HCO3- and Mg2 in salt ions and the content of available zinc, while the other ions did not fit well in regression analysis, and there was no significant correlation between HCO3- and Mg2 in the process of regression analysis.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S156.41

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