黄河三角洲典型地区土壤水盐动态规律、影响因素与预测模型

发布时间：2018-01-03 23:18

  本文关键词：黄河三角洲典型地区土壤水盐动态规律、影响因素与预测模型　出处：《山东农业大学》2017年博士论文　论文类型：学位论文

  更多相关文章： 黄河三角洲 土壤盐渍化 时空变异规律 影响因子 预测模型

【摘要】：随着全球的经济快速发展和人口激增,人地矛盾越来越突出,耕地资源的开发保护和土地退化的治理逐渐成为全球高度关注的热点问题。作为土地退化主要类型之一,土壤盐碱退化也已经成为一个全球性的生态问题。黄河三角洲是我国乃至世界造陆速度最快的河口三角洲之一,具有丰富的土地资源,是我国重要的后备土地资源区,然而,近50%的土地存在不同程度的盐渍化现象。目前,该区土壤盐渍化问题的系统研究尚较缺乏,仍需进一步的探讨。本文选取黄河三角洲典型地区垦利县、无棣县和“渤海粮仓”样板区作为研究区,在春、夏、秋、冬季典型时相,采用野外调查法采集0-15 cm、15-30 cm、30-45 cm、45-60cm土层土壤含盐量数据和0-15 cm土层土壤含水量数据。通过样点数据统计分析和GIS空间插值分析,研究土壤水盐含量的空间分异规律;构建土壤盐渍化动态变化模型,研究土壤水盐含量的时间变异规律;采用定性分析、定量分析和灰色关联度法,研究土壤盐渍化的主要影响因素;采用多元线性回归分析法,筛选主要影响因子,构建不同土层土壤含盐量预测模型;从县域、区域和微域尺度提出了土壤盐渍化防治和改良利用措施。得到以下主要结论:(1)研究区土壤水盐时空变异规律垦利县、无棣县和样板区土壤含水量均为中等变异强度。垦利县含水量较高的土壤主要分布于县域西南部黄河南岸和东部滨海区;无棣县含水量较高的土壤主要分布于县域北部滨海区。自2月至次年5月,样板区土壤含水量呈先升高再降低的月际性变化规律。垦利县和无棣县土壤含水量均表现为夏季最高,春秋次之,冬季最低,而年际间差异不显著。垦利县、无棣县和样板区土壤含盐量分别以2.0-5.0 g·kg-1、2.0-4.5 g·kg-1和2.0-6.0g·kg-1为主。垂直方向上,土壤剖面盐分特征均为底聚型。水平方向上,垦利县土壤含盐量自县域西部至东部逐渐升高,无棣县和样板区则自西南至东北逐渐升高。样板区表层土壤含盐量和土壤盐渍化的月际性差异较强,而随土层深度增加,月际性差异逐渐趋弱。垦利县夏季土壤含盐量最低,春秋次之,冬季最高,但仅稍高0.1-0.3 g·kg-1;土壤盐渍化程度表现为夏季向西北大幅减轻,秋季向东南大幅加重,冬季向东北小幅加重,次年春季向西南略有减轻。无棣县土壤含盐量则为夏季最低,冬季次之,春秋相近且最高;土壤盐渍化程度表现为冬季向东北略有减轻,春季向西南略有加重,夏季向东南大幅减轻,次年秋季向西北大幅加重。另外,垦利县和无棣县土壤含盐量和土壤盐渍化程度均存在年际间差异,但差异不显著,且随土层深度增加,年际间差异逐渐趋弱。县域各时期表层土壤含水量和含盐量均呈正相关,但并不显著;春秋季相关系数大于夏冬季。(2)土壤盐渍化影响因素分析黄河三角洲地区土壤盐渍化的主要影响因素为气候条件(蒸降比)、植被类型(植被覆盖度)、离渤海(黄河)远近、地形地貌(相对高程)、表层质地和土体构型(土体粘粒含量)、潜水埋深、地下水矿化度和人类活动。其中,蒸降比和地下水矿化度与土壤含盐量呈显著正相关;植被覆盖度、离渤海远近、相对高程、土体粘粒含量和潜水埋深与土壤含盐量呈显著负相关。同时,土壤含盐量受距路边远近、不同耕作措施、地形部位等因素影响表现出微域规律性和复杂性。在不同土层中,各影响因子对土壤盐渍化的作用强度均表现为地下水矿化度植被覆盖度潜水埋深土体粘粒含量离海远近相对高程。(3)土壤盐渍化预测模型构建及改良利用垦利县不同土层土壤含盐量的主要影响因子均为地下水矿化度、植被覆盖度、潜水埋深和土体粘粒含量。以这四个影响因子为自变量构建了不同土层土壤含盐量的多元线性回归预测模型,模型的调整决定系数分别为0.7632,0.8216,0.8156和0.7727,预测值与实测值的拟合精度均大于0.78,预测分布图的精度均大于75%,模型的精度较高,拟合效果较好,能较好的反映垦利县春季不同土层土壤含盐量的空间分布特征。在县域尺度上,分别划分了垦利县和无棣县的土壤盐渍化改良利用分区,根据各分区自然状况及存在的问题,提出相应的改良利用措施。在区域尺度上,根据“渤海粮仓”样板区土壤水盐运动规律,提出了不同时期土壤水盐运动的调节模式。在微域尺度上,提出了加强土壤耕作管理、培肥改良土壤和改善农田生态环境三个方面的措施。本文系统研究了黄河三角洲典型地区土壤盐渍化问题,摸清了土壤水盐动态规律及其影响因素,初步提出了土壤盐渍化预测模型,为土壤盐渍化的可持续利用和管理提供科学依据和技术支撑。采用野外调查、GIS与定量模型构建相结合的方法,为盐渍土的定量化分析提供了有效地手段。最后,根据不同尺度土壤盐渍化的特点,提出了针对性的改良利用措施,对研究区盐渍土的改良利用具有参考价值和指导意义。
[Abstract]:With the rapid development of the global economy and population growth, the contradiction between people and land become more and more prominent, the exploitation of the land resources protection and land degradation has become a hot issue of global concern. As the main types of land degradation, soil degradation has become a global ecological problem. The Yellow River Delta is one of delta China and the world's fastest reclamation, has rich land resources, is our country's important reserve land resources in the District, however, nearly 50% of the land has different degree of salinization phenomenon. At present, the system research the problem of soil salinization is still deficient, still need further discussion. This paper selects a typical Kenli county the Yellow River Delta, Wudi county and the "Bohai granary" model area as the study area, in the spring, summer, autumn and winter, the typical phase, using field survey collection 0-15 cm, 15-30 cm 30-45, cm, 45-60cm soil salinity data and 0-15 cm soil moisture data. Through sample data, statistical analysis and GIS spatial interpolation analysis, variation of soil water and salt content in model space; change dynamic of soil salinization, the time variations of soil water and salt content; qualitative analysis the quantitative analysis, and grey correlation method, the main influence factors of soil salinization; using multiple linear regression analysis, selecting the main influence factors, build soil salinity forecasting model; from the county, region and micro scale and puts forward some measures for prevention and improvement of saline soil. The main conclusions are as follows: (1) variability of soil water salt spatial in Kenli County, Wudi county and the model area of soil moisture are moderate variation. The strength of Kenli county with high water content of the soil is mainly distributed in the West The coastal area of southern the Yellow River and South Eastern Wudi County; high moisture content of the soil is mainly distributed in the northern coastal area. From February to May of the following year, yangbanqu soil moisture increased monthly variation and then decreased. Soil moisture in Kenli county and Wudi county were the highest in summer, spring and autumn time the lowest in winter, while no significant inter annual difference. Kenli County, Wudi County, the soil salt content and sample area respectively by 2.0-5.0 G - kg-1,2.0-4.5 G - kg-1 and 2.0-6.0g - kg-1. The vertical direction, soil salinity characteristics were poly type. The horizontal direction, soil salinity from Kenli county the west to the east gradually increased, Wudi county and sample area from southwest to northeast gradually increased. The difference monthly model of surface soil salinity and soil salinization is strong, and with the increase of soil depth, the monthly difference gradually weakening. The Kenli County summer Quaternary soil salt content is lowest, and highest in winter, but only slightly higher 0.1-0.3 g kg-1; soil salinization in summer to the northwest to the southeast fall sharply reduces sharply increased in winter to the northeast, slightly increased, the following spring slightly to reduce Wudi county. Soil salt content was the lowest in summer in winter, spring and autumn are similar, and the highest degree of soil salinization; winter to the northeast is slightly reduced, increased slightly to spring, summer to the southeast to the northwest the next year fall sharply reduces sharply increased. In addition, Kenli county and Wudi County, the soil salt content and soil salinization there were interannual differences, but the difference is not obviously, and with the increase of soil depth, the inter annual difference gradually weakening. The county during the period of surface soil moisture and salt content were positively correlated, but not significant; in spring and autumn than in summer and winter. The correlation coefficient (2) saline soil The main influence factors of influencing factors of soil salinization in the Yellow River Delta as the climatic conditions (evaporation precipitation ratio), vegetation types (vegetation coverage), from Bohai (the Yellow River) and topography (relative elevation), surface texture and soil (soil clay content), groundwater depth, groundwater salinity and human activities. Among them, evaporation precipitation ratio and groundwater mineralization and soil salt content showed a significant positive correlation; vegetation coverage, distance from Bohai, relative elevation, soil clay content and groundwater depth and soil salinity has significant negative correlation. At the same time, the soil salt content under different distance from the side of the road, farming measures, factors affecting the topographic position showed the micro domain regularity and complexity. In different soil, effects of these influencing factors on soil salinization showed groundwater mineralization degree of vegetation coverage of phreatic water from the sea near the soil clay content The relative elevation (3). Soil salinization forecast model and modified factor utilization in Kenli County Soil mainly affects the soil salinity are the mineralization degree of groundwater, vegetation coverage, groundwater depth and soil clay content. With these four factors as independent variables to construct a linear soil salt content in different layers of regression prediction model, adjustment coefficient of determination of model 0.7632,0.8216,0.8156 and 0.7727 respectively, the predictive value of the fitting precision and the measured value is greater than 0.78, the prediction accuracy of distribution was greater than 75%, the model precision is high, the fitting effect is good, can better reflect the Kenli County in the spring soil salinity distribution in spatial characteristics. The county scale, the author divided the improvement of soil salinization in Kenli county and Wudi County by partition, each partition according to the natural conditions and the existing problems, put forward corresponding improvement measures by At the regional scale, according to the movement of soil water and salt Bohai granary "model area, puts forward the regulation mode of soil water and salt movement in different periods. In micro scale, put forward to strengthen the management of soil tillage, fertilization and soil improvement of farmland ecological environment measures in three aspects. This paper studies in the Yellow River delta soil salinization problems, find out the factors of the dynamic rule of soil water and salt and its influence, proposed soil salinization forecast model, provide scientific basis and technical support for the sustainable utilization of soil salinization and management. Based on the field investigation, the construction method of the combination of GIS and quantitative model, provides effective means for quantitative analysis of saline soil. Finally, according to the characteristics of soil salinization in different scale, proposed the use of measures for improvement, improvement of saline soil in the study area with ginseng The value and guiding significance of the examination.

【学位授予单位】：山东农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S156.4
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本文编号：1376035