【作者】 吐尔逊·艾山；

【作者基本信息】 新疆大学 ， 生态学， 2012， 博士

【摘要】 由于地球上的不同地区在气候、母岩、地形、动物和植物等方面的不同，导致土壤的物理特性、化学特性、生物特性等方面存在明显的差异，形成了各种各样的土壤类型。在特定的时间和空间尺度上，某一区域的土地退化（如盐渍化等）及演变必然会导致该区域范围内土壤特性的空间变异性。因此很有必要在时间和空间序列上对土壤特性的时空变异性进行研究，以便更准确地了解土壤特性时空变异和区域生态环境之间的关系。本文运用RS/GIS技术，采用相关分析、传统统计学和地统计学相结合的方法，首先，研究渭-库绿洲盐渍化土壤为主的各景观类型的时空分布与景观格局的变化趋势；然后，分析渭-库绿洲土壤含盐量、矿化度、电导率、含水率、PH值、八大离子等土壤特性的时空变异情况，及其揭示其绿洲土壤特性的时空变异规律及相互之间的关系；最后，研究地下水埋深及地下水矿化度的变化规律及原因。这对研究区土地的合理利用、了解土壤的结构和功能、合理的水资源灌溉利用、土壤盐碱化防治、改良和有效利用提供科学依据，从而对保护渭-库绿洲生态环境的稳定性做出贡献。本研究得出以下主要结论：1)采用遥感与地理信息系统技术，对研究区1989、2001、2006和2011年4期TM/ETM+影像进行分类与统计，获得各景观类型的面积及比例。在此基础上，采用转移矩阵、LUCC分析方法，对渭干河—库车河三角洲绿洲的以盐渍化土壤为主的景观类型的数量特征、时空分布及变化趋势进行分析。结果表明，各研究时间区段，研究区景观类型发生了明显变化。在1989～2011年这22a期间，研究区各景观类型中所占面积最大的为非盐渍地，非盐渍地面积呈一直增长的趋势，面积增加了1497.126km²；重度盐渍地面积呈明显减少的趋势，累计减少了1401.7km²，是减少面积最大、减少速度最快的土地类型；中轻度盐渍化地面积的变化不大，22a来减少了39.653km²，但空间上的变化较大；水体和其它地类所占面积有增长趋势，而2001～2011年期间，均有减少趋势。研究区景观格局分析结果表明，1989～2011年期间，研究区整体斑块团聚程度有所增加，斑块类型形成了良好的连接性，景观的异质性程度、景观的复杂性程度在减少，景观破碎度逐渐下降。2)研究区7次野外考察数据的土壤盐渍化及酸碱度的分级划分分析结果表明，不同采样时间土壤样品各层的平均土壤酸碱度均属于微碱性土。研究区土壤含盐量按其含量大小在土壤剖面中均呈自上而下的垂直分异规律，表明盐分具有强烈表聚性。土壤含盐量的空间变化分析结果表明，绿洲内部土壤含盐量小于绿洲外围。表层土壤含盐量的空间、时间尺度上的研究结果表明，研究区盐渍化土壤主要集中于研究区的东部和东南部，研究区西部和西北部含盐量较低。大体上具有从研究区的西北、西边区域向研究区东南和东部区域的方向增加的趋势。从时间尺度上，研究区春季土壤含盐量大于秋季含盐量，土壤含盐量往加重方向发展。根据土壤中CL^－/(2SO₄^2-)当量比值来进行盐渍化土壤分类结果表明，不同采样时间，绝大多数情况下，各层土壤盐渍化类型主要以硫酸盐渍土和氯化物-硫酸盐型盐渍土为主；研究区土壤中的硫化物在土壤剖面中均呈自上而下增多的趋势，而氯化物呈自上而下减少的趋势。3)土壤特性间的相关性分析结果表明，不同采样时间土壤含盐量、电导率与矿化度相互间具有较高的正相关性；绝大多数采样时间，含盐量、电导率、矿化度分别与PH值、含水量之间没有显著相关性；PH值与含水量之间也基本上没有显著相关性。研究区表层土壤含盐量与Na⁺、Cl^-、SO₄^2-离子之间具有比较好的正相关性。含盐量与Ca²⁺离子之间也有一定的正相关性。不同采样时间，含盐量与HCO₃^-之间均没有相关性，这因为HCO₃^-是土壤碱化特征的表现，碱化与盐化表现为相逆关系，碱化与脱盐过程密切相关，说明研究区土壤总体上没有脱盐现象。4)灌区38眼监测井的11年的地下水埋深和矿化度数据分析结果表明：每年春季地下水埋深空间变异性比其它季节大，这反映研究区地下水埋深一定程度上受春灌的影响，并通过地下水位多年月平均值变化和地下水位季节变化分析中可以得出，研究区春季地下水位最高，秋季地下水位最低。从灌区地下水位时空变化分析结果表明，研究区的平均地下水位总体上有下降趋势，地下水位从灌区上部往下部或边缘有上升特征。灌区大部分观测井地下水矿化度属于微咸水或咸水，地下水矿化度的季节性变化不太明显。但灌区地下水矿化度时空变化分析结果表明，1997-2007年期间，渭干河灌区地下水矿化度总体上有下降趋势。地下水矿化度也有从灌区上部往下部或边缘上升特征。更多还原

【Abstract】 The diversity of climate, parent rock, topography, animals and plants in variousregions on earth, leading to distinct difference on soil physio-chemical and biologicalproperties in the formation process of a variety of soil types. Land degradation （e.g.,salinization） and its evolution in a given region will inevitably cause the variability ofsoil characteristics in specific temporal and spatial scales. Therefore, it is necessary tostudy spatio-temporal variability of soil properties in time and space sequence to moreaccurately understand the relationship between the spatio-temporal variability of soilcharacteristics and its regional ecological environment.In this paper, we used RS/GIS technology with the combination of correlationanalysis, traditional statistics and geostatistics methods. Firstly, we conducted aresearch on spatio-temporal distributions of saline soil-based landscape types and itsvariation tendency. Then, we analyzed the temporal and spatial variation of soilproperties, such as soil salinity, conductivity, moisture content, pH value and the eightions. Finally, we studied the causes and variations of groundwater level andgroundwater salinity. This can be a scientific basis for the rational use of landresources, better understanding of the soil structure and function, reasonable use ofwater resources in irrigation, soil salinity control and improvement, and thus cancontribute to the eco-environmental stability protection in Weigan-Kuqa Oasis.This research paper draws the following main conclusions:1) The area and proportion of each landscape types acquired throughclassification and statistics on four different period of TM/ETM+images （1989,2001,2006and2011, respectively）, using remote sensing and geographical informationsystem technology. On this basis, quantitative characteristics, spatio-temporaldistributions and variations of landscape types were analyzed by transfer matrix andLUCC analysis method. The results show that the study area landscape type haschanged significantly during each period. From1989to2011, area of non-saline land is maximum in landscape types in the study area, and has shown an increasing trend,has increased1497.126km²; Severe salinized land has a constant decrease with acumulative reduction area of1401.7km², is the fastest and largest reduction land type;There was little change with decreased area of39.653km²in the moderate and slightsaline land in the past22years, but with a big spatial variation; Area water and otherland type had a rising trend from1989to2001, and had a decreasing tendency in theperiod from2001to2011. The results of landscape pattern analysis show that, plaquereunion has increased in the study area, plaque type formed a good connection, thedegree of heterogeneity and complexity of landscapes has reduced, fragmentationdegree was gradually declined.2) The results from soil salinization and PH value grading and analysis show thatall soil samples from different time and soil layers are belong to the slightly alkalinesoil. According to salt content size, Soil salt content in study area showed a top-downvertical differentiation characteristic in the soil profile, indicating that the salt has astrong property of surface gathering. The analysis on spatial variation of soil saltcontent showed that the oasis soil salt content is less than the oasis periphery. Theresults from spatial and temporal variation analysis of soil surface salt content showedthat saline soils are mainly concentrated in the east and southeast of the study area,soils in the west and northwest are with low salt content. In general, from west andnorthwest side to east and southeast corner of study area, soil salt content increasesgradually. From the time scale, soil salt content in spring was greater than in fall, soilsalt content kept increasing.Saline soil classification results by the equivalent ratio of CL^－/(2SO₄^2-) in thesoil showed that during different sampling time, chloride-sulfate and sulfate soilswere in the first place in different soil layers in the depth of10-30cm and30-50cm;Sulfides in the soil profile showed a growing trend from top to bottom, while thechloride reduced from top to bottom. 3) The results of correlation analysis on soil characteristics indicates that there ishigh positive correlation between soil salinity, conductivity and mineralization degree;there is no significant correlation between pH value and water content, and betweensoil characteristics above （salinity, conductivity and mineralization degree）,respectively; there is good positive correlation between topsoil salt content and Na⁺,Cl^-, SO₄^2-ions; There is also certain positive correlation between salt content andCa2+ion; In different sampling period, there is no correlation between salt content andHCO₃^-, because HCO₃^-is the performance of alkalization. There is an inverserelationship between alkalization and salinization process, and alkalization is closelyrelated to desalination. This illustrates that there is no desalination phenomenon in thestudy area.4) Analyzing results of groundwater depth and salinity data obtained from38monitoring well in the irrigation area during11-year period show that the spatialvariability of groundwater level in each spring larger than other seasons, reflecting thespring irrigation influence on groundwater level to a certain extent; It could beconcluded by analyzing Monthly average groundwater level changes and seasonalvariation of groundwater level, groundwater level in the study area reaches the top inspring, falls to minimum level in fall; The analysis on spatial and temporal changes ofgroundwater level showed that the overall average groundwater level of study areahas declining trend, while groundwater level is rising from upper part of irrigationarea to lower part or to fringe; groundwater of most of the monitoring wells werebrackish or salt water, and seasonal groundwater salinity were not changingsignificantly. The results from spatio-temporal variation analysis on groundwatersalinity in Irrigation area showed that groundwater salinity was decreasing during theperiod from1997to2007. Groundwater salinity was rising from upper part ofirrigation area to lower part or to periphery.更多还原