河套灌区土壤盐分分布及其影响因素初步分析

发布时间：2018-03-04 04:06

本文选题：河套灌区　切入点：土壤盐分　出处：《扬州大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以河套灌区为研究对象,在野外调研和采样基础上,采用描述性统计分析、地统计分析方法,对表层土壤盐分空间变异性进行了研究,并且探讨了导致灌区土壤盐分空间变异的自然和人为因素,研究成果可为干旱区土壤盐碱化的防治改良提供一定的科学依据。通过研究得到了以下主要结论：(1)统计分析和正态分布性检验表明：表层土壤(0-15cm)含盐量服从对数正态分布,具有较强的变异性；地下水位埋深服从标准正态分布,属中等变异水平。根据地统计学的原理可知,河套灌区地下水矿化度实测数据的分布都服从标准正态分布,流域内地下水矿化度具有明显的时空变异性。(2)半方差函数分析表明：2012年4月份和7月份表层土壤含盐量块金系数、地下水位埋深块金系数和地下水矿化度块金系数分别为20%、18%、18%、15%、24%和15%,具有较强的空间相关性,说明其空间变异受区域因素影响较大,区域结构性因素影响比较突出。(3)空间尺度上,地下水位埋深愈浅,表层土壤盐碱化程度愈重。而地下水矿化度与土壤含盐量空间变化趋势无明显关联性。时间尺度上,7月份地下水位埋深较4月份浅,而盐土范围有向重度盐碱化土壤过度的趋势。随着年内不同季节的变化,咸水(5g/L)的面积变化比较平缓,受季节变化的影响不大；其它几种水质类型则随季节出现明显的波动。(4)灌区多年平均进盐量大于排盐量,总体上处于一个积盐状态。在相同种植年限中,不同土地利用方式下,土壤盐分含量为林地草地耕地。在相同土地利用方式下,种植年限与土壤盐分含量成反比,随着种植年限的增加,盐分含量降低的幅度越来越小。林地的土壤盐分表聚性较为明显,耕地和草地的盐分在剖面分布呈表层低于底层的情况,盐分大量积聚在20-60cm。(5)河套灌区土壤盐分空间分布的差异主要取决于地下水位埋深空间分布、土壤类型与质地、土地利用类型与种植作物类型和灌溉作用过程等的共同作用。
[Abstract]:Taking Hetao Irrigation District as the research object, the spatial variability of surface soil salinity was studied by descriptive statistical analysis and geostatistical analysis based on field investigation and sampling. The natural and human factors that lead to the spatial variation of soil salinity in irrigated area were also discussed. The results can provide a scientific basis for the control and improvement of soil salinization in arid areas. The main conclusions are as follows: 1) the statistical analysis and normal distribution test show that the salt content of surface soil is distributed from logarithmic normal to 15 cm). It has strong variability, the underground water table buried depth is from the standard normal distribution, belongs to the medium variation level. According to the principle of geostatistics, the distribution of the measured data of groundwater salinity in Hetao Irrigation area is in accordance with the standard normal distribution. The semivariance function analysis of groundwater mineralization in the basin shows that the gold coefficient of salt content in surface soil was obtained in April 2012 and July. The gold coefficient of underground water table buried deep block and the gold coefficient of underground water mineralization are 20 ~ 18% and 15%, respectively, which have strong spatial correlation, indicating that their spatial variation is influenced by regional factors, and the influence of regional structural factors is more prominent on spatial scale. The shallower the groundwater table is, the more salinization degree of the surface soil is, but there is no obvious correlation between the salinity degree of groundwater and the spatial variation trend of soil salt content. In time scale, the buried depth of groundwater table in July is lower than that in April. However, the salinized soil has a tendency of excessive salinization. With the variation of different seasons in the year, the area of salt water (5g / L) changes slowly, but is not affected by the seasonal change. Other types of water quality fluctuated obviously with the season. 4) the annual average salt intake in irrigation area was larger than that of salt discharge, and it was generally in a salt accumulation state. In the same planting years, under different land use patterns, Under the same land use pattern, the soil salt content is inversely proportional to the soil salt content, and with the increase of planting years, The soil salt accumulation of woodland is more obvious, and the distribution of salt in the profile of cultivated land and grassland is lower than that of the bottom layer. The spatial distribution of soil salt in Hetao irrigation area mainly depends on the spatial distribution of groundwater table depth, soil type and texture, land use type and crop type and irrigation process.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S151.9

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