盐渍化灌区土壤空间变异及HYDRUS水盐模拟研究

发布时间：2018-01-30 23:18

本文关键词： 空间变异尺度效应多重分形 HYDRUS模型灌水模式　出处：《内蒙古农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：在河套灌区引黄水量大幅减少的背景下,对河套灌区土壤空间变异性及水盐模拟进行研究,对工农业经济发展、水资源利用及生态环境等各个方面都具有重大的现实意义。本文以河套灌区永济灌域和隆胜试验区两个尺度为背景,分析土壤颗粒组成、含水率、EC值及有机质含量的空间变异性,进而通过土壤水盐运移模型模拟土壤水盐运移过程,揭示不同质地土壤水盐动态变化规律,优化灌水调控模式,研究结果可为灌区管理决策提供理论依据。研究表明,两个尺度下,各指标的变异系数介于15.56%～133.05%之间,除隆盛试验区尺度的40～60cm 土层的粘粒含量和0～100cm所有土层的砂粒含量呈强变异性外,其它属中等变异性;在同一尺度下,土壤粘粒含量、粉粒含量及有机质含量的空间变异性随着土层深度的增加而增加,砂粒含量、含水率及EC值则反之;在不同尺度的同一土层深度,土壤含水率及有机质含量的空间变异性为永济灌域尺度大于隆胜试验区尺度,其它则反之。地统计结果显示,永济灌域尺度20～40cm 土层的粉粒含量、砂粒含量不存相关性,其余不同尺度各个土层的土壤粘粒、粉粒、砂粒含量、含水率及有机质含量属强烈的空间相关性和中等空间相关性。土壤EC值在隆胜试验区尺度呈较强烈的空间相关性,在永济灌域尺度呈弱空间相关性,40～60cm 土层无空间相关性。各指标的空间相关距离皆随着研究尺度的增大而增大。多重分形分析结果表明,各指标不同尺度不同土层均具明显的多重分形特征;土壤粘粒含量在隆胜试验区尺度全部土层及永济灌域尺度40～60cm 土层的空间分布是以小数值数据为主,其它土层反之;土壤粉粒和砂粒含量在两个尺度不同土层的空间分布均以大数值数据为主;含水率在永济灌域尺度0～20cm、20～40cm、40～60cm及80～100cm 土层及隆胜试验区尺度0～20cm、20～40cm 土层的空间分布以大数值数据为主,而其它土层反之;EC值在隆胜试验区尺度80～100cm 土层及永济灌域尺度20～40cm 土层的空间分布以大数值数据为主,其它土层反之;有机质含量仅在隆胜试验区尺度上0～20cm、20～40cm及80～100cm 土层的空间分布以小数值数据为主,其它土层和永济灌域尺度全部土层均反之。数值模拟结果表明,砂壤土的适宜灌水量在玉米生育期为300 mm,秋浇期为150mm;粉砂壤土的适宜灌水量在玉米生育期为330 mm,秋浇期为180mm;粉土的适宜灌水量在玉米生育期为360mm,秋浇期为210mm。
[Abstract]:The spatial variability of soil and the simulation of water and salt in Hetao Irrigation area were studied under the background of large reduction of water diversion from the Yellow River in Hetao Irrigation area, and the economic development of industry and agriculture was also studied. The utilization of water resources and ecological environment are of great practical significance. Based on the two scales of Yongji Irrigation region and Longsheng Experimental area in Hetao Irrigation District, this paper analyzes the composition of soil particles and water content. The spatial variability of EC value and organic matter content, and then simulate the process of soil water and salt migration through soil water and salt migration model, reveal the dynamic changes of soil water and salt in different texture, and optimize irrigation control model. The results can provide a theoretical basis for the management decision of irrigation district. The results show that the coefficient of variation of each index is between 15.56% and 133.05%. Except for the strong variability of clay content in 40cm-60cm soil layer and the sand content in all soil layers of 0 ~ 100cm, the others belong to moderate variability. At the same scale, the spatial variability of soil clay content, silt content and organic matter content increased with the increase of soil depth, while the sand content, moisture content and EC value were reversed. At the same soil depth of different scales, the spatial variability of soil moisture content and organic matter content is that the scale of Yongji irrigation area is larger than the scale of Longsheng experimental area, and the other is the opposite. The geostatistical results show that. There is no correlation between the silt content and the sand content in the irrigation area of Yongji irrigation area, but the clay, silt and sand content in the other soil layers of different scales. Soil EC values showed strong spatial correlation in the scale of Longsheng experimental area and weak spatial correlation in the scale of Yongji irrigation area. There is no spatial correlation in 400-60cm soil layer. The spatial correlation distance of each index increases with the increase of research scale. Multifractal analysis results show that. Each index has obvious multifractal characteristics in different scales and different soil layers. The spatial distribution of soil clay content in all soil layers in Longsheng experimental area and in 4060 cm soil layer in Yongji irrigation area is dominated by small numerical data, whereas the other soil layers are not. The spatial distribution of soil silt and sand content in two different soil layers is dominated by large numerical data. The water content is at the scale of 0 ~ 20 cm, 20 ~ 40 cm, 40 ~ 60 cm and 80 ~ 100 cm soil layer in Yongji irrigation area, and the scale is 0 ~ 20 cm in Longsheng experimental area. The spatial distribution of 20 ~ 40cm soil layer is dominated by large numerical data, while other soil layers are not. The spatial distribution of EC value in the scale of 80 ~ 100cm soil layer in Longsheng experimental area and 204cm soil layer in Yongji irrigation area is dominated by large numerical data, whereas the other soil layers are inversely distributed. The spatial distribution of organic matter content on the scale of 0 ~ (20) cm ~ (20) ~ (20) cm ~ (20) ~ (40) cm and 80 ~ (100) cm soil layer is dominated by small numerical data. The numerical simulation results showed that the suitable irrigation amount of sandy loam was 300 mm in maize growth period and 150 mm in autumn. The suitable irrigation amount of silty loam was 330 mm in maize growth period and 180 mm in autumn period. The suitable irrigation amount of silt was 360 mm in maize growth period and 210 mm in autumn.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.4;S274

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