【作者】 王雪梅；

【作者基本信息】 新疆大学 ， 自然地理学， 2010， 博士

【摘要】 土壤盐渍化是当今世界上土地荒漠化和土地退化的主要类型之一,也是世界性的资源问题和生态问题,对干旱半干旱地区绿洲农业可持续发展具有重要阻碍作用,并对绿洲生态系统的稳定构成极大威胁。因此,正确评价和预防土壤盐渍化对促进干旱区绿洲农业生产和区域可持续发展具有重要的现实意义。本研究选择具有长期研究基础的渭干河—库车三角洲绿洲作为典型研究区域,在景观生态学和可持续发展的理论指导下,以研究区多时相遥感影像数据和多年野外观测数据为基本信息源,运用空间信息技术,统计学及景观生态学等分析方法,从不同尺度对渭干河—库车河三角洲绿洲土壤盐渍化的变化及其生态效应进行综合、集成的研究。通过科学把握区域土壤盐渍化动态变化和生态环境演变的过程和规律,为区域生态环境恢复与重建、土地可持续利用的决策提供科学依据。同时,对渭干河—库车河三角洲绿洲土壤盐渍化及其生态效应的研究亦是全球变化的一种区域响应。通过对区域尺度的土壤盐渍化问题进行深入研究,本研究得出以下主要结论：1)以1989年、2001年TM/ETM数据以及2007年ALOS数据为主要遥感信息源,采用遥感分析方法和地理信息系统技术相结合,建立渭干河—库车河三角洲绿洲土壤盐渍化时空动态数据库。在此基础上,采用图谱模型、转移矩阵和LUCC分析模型方法,开展了渭干河—库车河三角洲绿洲土壤盐渍化遥感动态变化研究,对渭干河—库车河三角洲绿洲土壤盐渍化数量特征、时空分布、变化趋势进行了探索。研究结果表明,在1989-2007年间,渭干河—库车河三角洲绿洲重度盐渍地面积呈现明显下降趋势。中度盐渍地面积虽然发生上下波动,但整体面积却有所增加。轻度盐渍地面积则呈现较为明显的下降趋势,非盐渍地面积增长显著；同时,结合盐渍土空间插值结果分析,认为该绿洲盐渍地主要分布于渭干河和库车河的下游,塔里木河的北部,绿洲的西南、南部、东部和东南部地区,可溶性盐以氯化物为主,并伴有少量的硫酸盐-氯化物类。盐渍地在绿洲内部呈条形状分布,而在绿洲外缘呈片状分布,主要分布趋势表现为由绿洲内部向外部的转移。2)在对三期遥感影像判读分析的基础上,开展渭干河—库车河三角洲绿洲土地利用／土地覆盖动态变化研究,建立研究区土地利用／土地覆盖的时空动态数据库。同时,运用多种模型方法对渭干河—库车河三角洲绿洲土地利用／土地覆盖的动态变化进行定量分析,揭示其空间分布及变化规律。在1989-2007这18年间,渭干河—库车河三角洲绿洲LUCC的总体变化趋势：绿洲面积有一定幅度的扩张；在土地利用／土地覆盖类型上主要表现为耕地和居民区面积的持续增加和天然林地、草地和盐渍地面积的减少。3)以野外实测数据为主要数据源,通过各盐分特征量的空间分布的分析,认为在不同采样时间,土壤含盐量、电导率、TDS和八大盐离子在三层均呈T型分布：0-10cm>10-30cm>30-50cm,盐分表聚强烈,各盐分特征量存在一定的空间变异性；通过对电导率、TDS、土壤PH值、含水量以及盐离子与含盐量进行相关分析和回归分析,结果表明：电导率、K+ + Na+与含盐量相关关系极其显著(P<0.01),回归模型拟合效果良好。TDS和Cl-与土壤含盐量之间有显著的相关关系(P<0.05),回归模型拟合效果较好。而土壤PH值、含水量、CO32-、HCO3-、SO42-、Ca2+以及Mg2+与含盐量的回归模型效果并不显著；通过主成分分析认为,在该绿洲土壤系统中,以Cl-和K+ + Na+为主的第一主成分代表了土壤盐化状况,以SO42-、Mg2+和Ca2+为代表的第二主成分和第三主成分反映了土壤的结构状况,而以CO32-和HCO3-为主的第四主成分则代表了土壤的碱化特征。4)运用数量生态学的方法对渭干河—库车河三角洲绿洲的盐生植被及其土壤化学因子进行分析,结果表明,土壤盐分和土壤PH值与丰富度指数(R)、多样性指数(H’)和均匀度指数(E)负相关关系显著(P<0.05),而与优势度指数(C)具有显著正相关关系(P<0.05)；土壤盐分是影响这一地区植被分布的关键因子,同时土壤PH值也对该区盐生植被的分布有着一定的影响；根据研究区盐生植物分布规律显示,柽柳、盐穗木和芦苇这三种盐生植物广泛分布于各种盐渍化生境,具有较宽的生态分布幅度和很高的耐盐能力。5)以景观生态学理论为指导,参照Costanza R.的生态系统服务价值的评价方法,对渭干河—库车河三角洲绿洲生态系统服务功能价值进行了评价。认为景观结构的动态变化对生态系统服务功能价值影响显著；同时,各生态系统单位面积的服务价值对生态系统的服务总价值也有一定的影响。通过研究区土壤盐渍化对生态系统服务价值的损失分析,在1989-2007年间,土壤盐渍化对生态系统服务价值的损害作用在不断下降；由林地和草地发生土壤盐渍化造成的生态系统服务价值缺失最为严重,在总缺失价值中占有较大比例；土壤盐渍化对耕地和水域生态系统服务价值损失最小,所占比例较小；土壤盐渍化对气候调节、水源涵养和废物处理功能损失价值较大,而对气体调节、土壤形成与保护以及原材料生态功能损失价值较小。由于区域土壤盐渍化形成机理的复杂性决定了土壤盐渍化的研究将从多层次、多角度、多方法等方面进行综合研究。因此,从景观生态学的角度,在大尺度范围内探索土壤盐渍化动态变化规律,土壤盐渍化与相关生态系统的相互关系、作用机理以及盐渍化区域生态恢复的自组织机理等方面的研究将是今后努力探索的主要方向。更多还原

【Abstract】 Soil salinization is a major type of land desertification and degeneration in the worldwide today. Soil salinization is also a major constraint and obstacle of oasis’ agricultural sustainable development in arid and semiarid areas, and poses the enormous threat stably to the oasis ecosystem. Therefore, it has the vital realistic significance to evaluate accurately and prevent scientifically soil salinization in order to promote oasis’agricultural development and regional sustainable development in arid areas.This study selected the delta oasis of Weigan and Kuqa River as the typical research area, which has a long-term researched foundation in Xinjiang’s arid area. Under the theory of landscape ecology and sustainable development, used different periods’remote sensing satellite data and long-term field measuring data as the basic data sources, used spatial information technology (RS, GIS, GPS), statistics technology and landscape ecology method, to research synthetically the change of soil salinization and ecologic effects in the delta oasis of Weigan and Kuqa River. Grasping scientific the change rule of the soil salinization and eco-environment in different spatial and temporal scale which could provide scientific basis for the regional eco-environment construction and land sustainable development. At the same time, studying on the change of soil salinization and ecologic effects in the delta oasis of Weigan and Kuqa River is a regional respond to the change of global. Through the research of the regional soil salinization, this thesis indicates some major conclusions as the following:1) Taking the 1989’s,2001’s TM/ETM+ and 2007’s ALOS satellite data as the basic information sources, launch the research of soil salinization change trends. On the foundation of data basic, using the methods of the geography model, transfer matrix, the LUCC model to analysis the change of soil salinization and explored the quantitatively the distribution and the change trends of soil salinization. The results indicate the areas of severely soil salinization presented the obvious decreased trends in the delta oasis of Weigan and Kuqa River from 1989 to 2007; the areas of moderately soil salinization present the fluctuation up and down, but the whole areas was decreased; the slightly soil salinization presented the obvious decreased trends, while the areas of non-salinization showed the trendy of dramatically raise. At the same time, union salty chronometers space interpolation result analysis, the salinized soil is mainly distributed in the lower reaches of the Weigan and Kuqa River, the northern margin of the Tarim River, the west-southern, the southern, and the eastern, the east-southern of oasis. The soluble salt by the chloride primarily, and is accompanied by the few sulfate-chlorination category of things. The distributions of salinized soils are stripe inside oasis, while are slices in the marginal oasis. The main distribution trendy displays the transfer from inside to outside of oasis.2) On the foundation of analysis the satellite data (TM/ETM+ and ALOS), established the spatial and temporal data basic of LUCC in the delta oasis of Weigan and Kuqa River by the combination of RS and GIS. On the foundation of data basic, using the methods of the geography model, transfer matrix, the LUCC model to analysis the change of LUCC, reveal the distribution and change laws of LUCC quantitatively. The results indicate:the whole tendency is the surely increasing of oasis areas in the delta oasis of Weigan and Kuqa River from 1989 to 2007.The type of LUCC showed the continued increasing of the human living region, and the decreased of the natural forest, grass and soil salinization.3) Taking the data of field investigations as the brief data sources, analyzed the spatial distributions of the characteristics of soil salinization. The results indicate:the soil salt content, conductivity, TDS and eight ions assume "T" in three distribution, which is 0-10cm>10-30cm>30-50cm. The salty chronometers gather intensely in the different sample time. The characteristics of soil salinization have different changeability in the space. Using the analysis of correlation and regression to study the relations between the soil compositions, the results indicated the relations of correlation between content of salt with conductivity and K++Na+ are very positive significantly(P<0.01), and the fitful of regression models are very well; the relations of correlation between content of salt with TDS and Cl- are positive significant (P<0.05), and the fitful of regression models are well too; while, the models of regression between content of salt with soil PH, content of water, CO32-,HCO3-, SO42-,Ca2+ and Mg2+ are not significant. Through the principal components analysis, think in this oasis soil system, the soil mantle characteristic available four principal constituents manifests:the first principal components have represented the soil salt chemicals condition, the second principal components and the third principal components have reflected the soil structure condition, but the fourth principal components have represented the soil alkalize characteristic.4) Using the method of numerical classification, analyze the relationship of halophytes with soil chemical factors in the delta oasis of Weigan and Kuqa River. The results indicated that the characteristics of soil salt and soil pH are negative correlative to richness index, diversity index, and evenness index significantly (P<0.05), while are positive correlative to dominance index significantly (P<0.05). Soil salinity and soil PH turned up to be the main determinants to the distribution patterns of halophytes. The soil salinity affects this local vegetation distributed essential factor, simultaneously the soil PH value also lives the vegetation to this area salt the distribution to have certain influence. According to the distribution of vegetation, show Tamarixram osissina, Halostachys caspica with Phragm ites australis distribute to various living environment of salinized soil. These vegetations have wide ecological distribution scope and high ability fitting to salinized soil.5) On the basis of the theory of landscape ecology, referring to methods of landscape pattern ecosystem service values proposed by Costanza R. analyze the ecosystem service value change in the delta oasis of Weigan and Kuqa River. The result manifests that the landscape structural change and the value of annual ecosystem services have significant affections on ecosystem service value. Analysis the losses value of ecosystem service which be caused by soil salinization. The result indicates that the damaged of ecosystem services value by soil salinization is falling from1989 to 2007. The ecosystem service values of forest and grass have much loss, which have large proportions. While, plough and waters which have a little proportions lost little ecosystem service values. Soil salinization causes much ecosystem service values loss to climate control, water source self-control and waste treatment, and little ecosystem service values loss to gas control, soil formed and protected with raw material.Because of the complicated characteristics about the formation mechanism of soil salinization, the study on soil salinization will be synthetically from multi-level, aspects and multiple perspectives, multi-methods. Therefore, on the point of landscape ecology, discovering the dynamic change rule in large scale, studying the correlation, the mechanism of interaction, the salinized region ecology self-restore of soil salinization with ecosystem will be the main considered direction in future research.更多还原