Knowledge Resource Center for Ecological Environment in Arid Area
| 民勤灌区地下水动态特征及其与土壤盐渍化的关系 | |
| 其他题名 | Dynamic characteristics of groundwater and its relationship with soil salinization in Minqin Oasis, Northwest of China |
| 李会亚 | |
| 出版年 | 2017 |
| 学位类型 | 硕士 |
| 导师 | 冯起 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 民勤绿洲位于西北干旱区，由于自然和人为因素的共同作用，地下水矿化度普遍偏高。对于缺水的民勤绿洲来说，利用高矿化度地下水灌溉成为缓解农业用水紧张的有效途径，但地下水中的盐分离子直接进入土壤，极易造成土壤盐渍化。为防止民勤成为“第二个罗布泊”，国家从2007年开始实施《石羊河流域重点治理规划》，每年从外流域向民勤调水，该规划的实施对民勤绿洲生态恢复产生了积极影响。本文基于研究区内采集的地下水样数据和表层土样数据，利用经典统计学与地统计学方法，研究地下水的时空动态和地下水化学演化驱动机理，以及土壤盐分的空间变异，并利用灰色关联分析和冗余分析研究地下水动态与土壤盐渍化的关系，提出防治土壤盐渍化的水盐调控措施。结果表明：（1）研究区地下水埋深呈现出4月开始下降，8–9月达到最低值，10月以后恢复上升的季节性变化趋势。从1999–2007年，研究区地下水埋深逐年下降；2007年以后，泉山区和湖区的部分区域地下水埋深出现回升。由灰色关联分析知，气象因素对研究区地下水埋深动态变化的影响更大。（2）研究区地下水矿化度均值为3.142 g/L，从西南到东北方向呈明显的递增趋势。从2010–2014年，地下水矿化度均值由3.349 g/L下降到3.142 g/L，说明调水入民政策对该区地下水质的改善起到积极的作用。坝区地下水水化学类型以SO4–Na型、SO4–Mg型和SO4–Ca型为主，泉山区以Cl–Mg型和SO4–Na型为主，湖区以SO4–Na型为主。沿着坝区→泉山区→湖区方向，地下水水化学类型逐渐趋于单一。研究区地下水水化学演化主要受到蒸发浓缩、阳离子交换和溶滤作用的共同影响。（3）盐渍土主要分布在坝区东坝镇东部、泉山区双茨科乡南部以及湖区西渠镇北部和东湖镇东部的区域。从2010–2014年，该区表层土壤全盐从2.645 g/kg下降到0.947 g/kg，尤其是湖区下降的最为明显，说明调水入民政策对湖区土壤盐分的淋洗起到了积极的作用。（4）在研究区的地下水浅埋区，地下水埋深对土壤盐渍化的影响较为明显。坝区表层土壤全盐随着地下水矿化度的升高呈三次方增加的趋势，泉山区表层土壤全盐随着地下水矿化度的升高则呈对数增加的趋势。根据灰色关联分析和冗余分析的结果可知，坝区地下水中的Na+和Cl–含量对表层土壤全盐的影响最大，而泉山区是地下水中的Ca2+和Cl–，湖区则是地下水中的Na+和SO42–。（5）针对民勤灌区存在的土壤盐渍化威胁，应该大力推广膜垄沟灌，定期进行土壤洗盐作业，并增加耐旱耐盐经济作物的种植比例。 |
| 英文摘要 | Minqin Oasis is located in the northwest arid area of China, due to the interaction of natural factors and human factors, the groundwater generally has a high mineralization degree. For Minqin oasis lack of surface water, it has become a effective way to relieve water shortage through using high salinity groundwater for irrigation, but the salt ions of groundwater can directly get into the soil. Under the action of strong evaporation, the surface soil easily produces secondary salinization. In order to prevent the Minqin Oasis become “the second Lop Nor”, “Key Management Plan of Shiyang River Basin” was implemented in 2007, and this plan has a positive impact to ecological restoration of Minqin Oasis. In this paper, base on the groundwater samples data and topsoil salinity data, the spatial and temporal dynamic characteristics of groundwater depth, the evolution mechanism of groundwater hydrochemistry and the spatial variability of soil salinity are studied by the method of Classical Statistics and Geostatistics. The relationship between groundwater and soil salinization is studied by using the method of Gray Relation Analysis and Redundancy Analysis. The result shows that:(1) The seasonal variation of groundwater depth in the study area: from April, the groundwater depth began decreasing; in August or September, it reached the lowest value; in October, it began to recover gradually. From 1999 to 2007, the groundwater depth of the study area showed a downward trend by year. After 2007, the groundwater depth of some region in Quanshan and Huqu had a rise trend. According to the Grey Relation Analysis, the meteorological factors had greater influence on the dynamic change of groundwater depth in the study area.(2) The average value of mineralization degree of groundwater was 3.142 g/L. The mineralization degree of groundwater showed an obvious increasing trend from southwest to northeast. From 2010 to 2014, the mineralization degree of groundwater decreased from 3.349 g/L to 3.142 g/L, indicating that the policy of water diversion had a positive impact on the improvement of groundwater quality in this area. The main groundwater chemical types in Baqu were SO4–Na, SO4–Mg and SO4–Ca, and those in Quanshan were Cl–Mg and SO4–Na, and that in Huqu was SO4–Na. Along Baqu→Quanshan→Huqu, the groundwater chemical types tended to be single. Evaporation concentration, cation exchange and dissolution were the main hydrological chemical processes which controlled the groundwater chemical evolution.(3) The high value of total salt mainly distributed in the east of Dongba township, the south of Shuangcike township, and the east of Huqu. From 2010 to 2014, the total salt decreased from 2.645 g/kg to 0.947 g/kg, especially the total salt of Huqu decreasing obviously, indicating that the policy of water diversion had played a positive role to the leaching of soil salt in Huqu.(4) In the shallow area of groundwater depth, the influence of groundwater depth on soil salinization was obvious. The topsoil salt of Baqu had a three times increase with the mineralization degree of groundwater increasing, and the topsoil salt of Quanshan had a logarithmic increase with the mineralization degree of groundwater increasing. According to the results of the Gray Relation Analysis and Redundancy Analysis, the content of Na+ and Cl– of groundwater had the greatest influence on the content of topsoil salt in Baqu, and the content of Ca2+ and Cl– of groundwater had the greatest influence on the content of topsoil salt in Quanshan, and the content of Na+ and SO42– of groundwater had the greatest influence on the content of topsoil salt in Huqu.(5) Facing with the threat of soil salinization in Minqin Oasis, furrow irrigation under plastic mulch should be vigorously promoted, leaching soil salt should be done regularly, and the proportion of drought tolerance and salt tolerance cash crops should be increased. |
| 中文关键词 | 地下水动态 ; 土壤盐渍化 ; 空间变异性 ; 冗余分析 ; 民勤绿洲 |
| 英文关键词 | groundwater dynamics soil salinization spatial variability Redundancy Analysis Minqin Oasis |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287948 |
| 推荐引用方式 GB/T 7714 | 李会亚. 民勤灌区地下水动态特征及其与土壤盐渍化的关系[D]. 中国科学院大学,2017. |
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