Knowledge Resource Center for Ecological Environment in Arid Area
| 荒漠绿洲土壤优先流特征及生态水文效应 | |
| 其他题名 | Characteristics of preferential flow and its ecohydrological implications in desert oasis |
| 闫加亮 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 赵文智 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 土壤优先流是土壤水和溶质快速通过部分土壤剖面向下运移的一种物理现象。它不仅能够影响土壤的碳氮等养分循环，而且也能够对土壤水运动和地下水水质产生影响。近30年来，关于土壤优先流研究主要集中在湿润、半湿润地区，对干旱区半干旱区的，尤其是绿洲生态系统的土壤优先流特征及影响因素的研究较少, 已经成为认识绿洲土壤水运动、量化绿洲灌溉深层渗漏量、提高水肥利用效率以及降低浅层地下水污染的风险的瓶颈。本文以中国生态系统研究网络临泽站为依托，选择天然荒漠草地、人工梭梭固沙林和杨树人工阻沙林等典型植被类型，以及开垦10年、30年和百年以上的绿洲农田，利用染色示踪技术研究了土壤优先流特征及其影响因素以及土壤优先流的生态水文效应。研究结论如下：1）土壤优先流特征天然荒漠草地土壤水主要以基质流向下运移，仅在染色剖面底部有一小部分不稳定的湿润锋；梭梭人工固沙林的土壤优先流呈现明显的漏斗流形态；杨树人工阻沙林的土壤优先流则为典型的不稳定流；绿洲农田土壤优先流形态随着开垦年限的增加而发生变化，表现在开垦10年农田的土壤优先流呈现明显的不稳定流形态，而开垦30年以上的农田则呈现出明显的大孔隙流特征。2）影响土壤优先流的因素天然荒漠草地、梭梭人工固沙林和杨树人工阻沙林受地表特征和土层结构等样地位置固有特性的影响，例如，杨树人工阻沙林地表粘土层的裂隙结构对土壤优先流有重要影响；梭梭人工固沙林土壤优先流主要受沙丘本身倾斜纹理结构的影响；天然荒漠草地和杨树人工阻沙林的土壤优先流最大入渗深度受土壤剖面粘土层的影响。绿洲过渡带不同位置的土壤优先流强度都随降水量的增加而增强。总体上荒漠绿洲土壤优先流强度都随降水量的增加而增强，当降水量超过15 mm时，优先流强度明显增强。绿洲农田土壤粘粒含量和土壤有机碳均对土壤优先流强度有影响，但土壤有机碳在一定程度上掩盖了土壤粘粒对土壤优先流的影响。施用有机肥和提高土壤含水量都可以有效的增加土壤优先流的强度，提高土壤含水量能够显著增加有机碳含量低的土壤的优先流强度。在开垦前10年，绿洲农田土壤优先流强度随着灌溉量的增加呈线性增加，开垦10年以上农田的土壤优先流强度与灌溉量没有显著的线性关系。由垄沟耕作引起的耕作层土壤容重和土壤含水量以及土壤表面裂隙密度的差异对耕作层的优先流特征有重要影响，垄与沟的土壤优先流路径数量在土壤深度7.3 – 16.7 cm 处差异显著（p< 0.01）。平均灌溉量120 mm时优先流的最大入渗深度为43.1 ± 5.9 cm，而灌溉量55 mm的样方由于受到蚂蚁洞的影响，优先流最大入渗深度可达68.3 ± 7.6 cm。根系是影响土壤优先流强度的重要因素之一。但在荒漠绿洲区并不是所有的根系对土壤优先流都有贡献；植被根系对土壤优先流的影响随着土壤粘粒含量的增加而发生变化，总的趋势是随着土壤粘粒含量增加粗根系对土壤优先流的影响减弱，细根系对土壤优先流的影响加强。3）土壤优先流的生态水文效应在绿洲过边缘小降水事件的土壤优先流对一年生草本的种子萌发没有显著影响，而是初始土壤含水量对一年生草本的种子萌发影响显著；杨树人工阻沙林土壤优先流对林下生于裂隙内和裂隙外草本的个体密度和净初级生产力有显著影响。在单次平均灌溉量120 mm的情况下，开垦10年、30年和百年农田土壤优先流现象对地下水水质影响的风险非常低。 |
| 英文摘要 | Preferential flow is a physical process describing how water and solutes move along certain pathways through soil while bypassing other volume tractions of the porous soil matrix. Preferential flow could not only affect soil carbon and nitrogen nutrient cycling; it also could influence groundwater quality. Nearly 30 years, many scholars had performed a large number of studies about preferential flow in the wet and semi-wet land. But little is known about preferential flow and its effects on vegetation under natural conditions in arid and semi-arid desert oasis. That limited us to knowing the soil water movement , quantizing oasis irrigation deep seepage quantity, increasing water use efficiency and reducing the risk of shallow groundwater pollution The study was conducted near the Linze station and selected three experiment sites in the desert oasis fridge and oasis cropland, respectively. We used dye tracer technique to study the characteristics and influence factors of soil preferential flow and Hydro-ecological implications. The main results were as follows:1) Characteristics of preferential flow in desert oasisIn the desert oasis fridge, the characteristics of preferential flow of the oasis ecotone and cropland showed different patterns. At the nature desert grass site, stained soil profiles showed that the soil water was dominated by the matrix flow and there was only a small part of the unstable flow at the bottom of the stained soil profiles, Funnel flow was found at the artificial sand-fixation forest of Haloxylon site; unstable flow was found at the artificial sand-trapping forest of Populus site.In oasis farmland, preferential flow patterns changed with the increasing years of cropland. Soil preferential flow showed typical unstable flow at 10-years-old cropland, while it showed the characteristics of obvious macropore flow at the more than 30 years of farmland.2) The impact factors of preferential flow in desert oasisThe preferential flow was effected by inherent characteristics of the experimental site in the desert oasis fridge. For example, at the artificial sand-trapping forest of Populus site, soil surface crack has an important role in soil preferential flow, and inclined sand layer structure was the main factor of the preferential flow. The maximum infiltration depth was all affected by the inter-clay layer at the nature desert grass and artificial sand-trapping forest of Populus sites. In all, preferential flow is enhanced with the increase of rainfall depth and soil preferential flow strength enhanced obviously when the rainfall depth of more than 15 mm.In oasis farmland, soil clay content and soil organic carbon are all influential to soil preferential flow, but soil organic carbon can obscured the influence of soil clay on soil preferential flow. organic matters and high soil moisture content can effectively increase the strength of the soil preferential flow. Improving soil moisture content can significantly enhance the strength of preferential flow in spite of low soil organic carbon soil. The each indices of preferential flow presented obviously linear relationship at the 10 year old cropland, and was no significant linear relationship at the 30 years old and over-hundred year old cropland. Differences of soil bulk density, soil water content and soil surface crack being induced by cultivation had important effects on the characteristics of preferential flow, and stained path number significantly greater at the ridge than at the furrow (p < 0.01) at the depth of 7.3-16.7 cm of soil profiles. The maximum infiltration depth of irrigation 120 mm was 43.1 ± 5.9 cm, while the maximum infiltration depth of irrigation 55 mm could reach 68.3 ± 7.6 cm because of the ant hole.The plant root is one of the important factors that affect soil preferential flow. But not all of the root system has a contribution on soil preferential flow in the desert oasis fridge and oasis farmland. And the importance of the vegetation root on soil preferential flow increased with the soil clay content increased. The general tendency was that the effect of the root system on soil preferential weakened with the soil clay content increase, while the influence of fine root system on soil preferential flow enhanced.3) Eco-hydrology implications of preferential flowIn desert oasis fridge, soil preferential flow of little rainfall event had no significant impact on seed germination of the annual herb, while the initial soil water content had a significant effect on seed germination of the annual herb. At the artificial sand-trapping forest of Populus site, soil preferential flow phenomenon had significantly affect the individual density and aboveground net primary productivity of herbs. At the oasis cropland, Preferential flow did not pose a risk to groundwater quality at the three experimental sites after 120 mm irrigation. |
| 中文关键词 | 绿洲化 ; 土壤质地 ; 土壤有机碳 ; 土壤含水量 ; 地下水 |
| 英文关键词 | Oasisization Soil texture Soil organic carbon Soil water content Ground water |
| 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/2XILL650/287678 |
| 推荐引用方式 GB/T 7714 | 闫加亮. 荒漠绿洲土壤优先流特征及生态水文效应[D]. 中国科学院大学,2016. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [闫加亮]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [闫加亮]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [闫加亮]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
