Knowledge Resource Center for Ecological Environment in Arid Area
| 科尔沁沙地沙丘土壤水分运移与水分特征研究 | |
| 其他题名 | Soil moisture transport and water characteristics in the Horqin Sandy Land |
| 杨婷婷 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 王安志 ; 阿拉木萨 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 土壤水分是干旱半干旱地区植物生长的主要限制因子，植被建设又是防治荒漠化的有效措施。在长期沙地治理过程中，大面积的沙丘人工植被建设方法被广泛采用，取得了显著的固沙效果。但同时对其水分平衡过程产生了不利影响，造成了沙丘系统的水分失衡，即：人工植被建设将流动沙丘改造为固定沙丘后，增加了沙丘表面植被盖度，改变了地表形态，增加了水分消耗，增加了沙丘土壤水分的流失，将会对固沙植被的长期稳定存在产生影响，降低固沙效果。本文以科尔沁沙地为研究对象，调查并观测了10个不同植被覆盖度沙丘的植被特征、土壤水分和地势地貌等，进而分析了沙丘土壤水分季节动态变化及空间分布规律。同时利用HYDRUS模型对流动沙丘土壤水分运移和土壤蒸发对地下水埋深的响应进行研究，明确沙丘的土壤水分平衡特征。并通过土壤水分与植被盖度间相互关系的比较分析，提出了科尔沁沙地沙丘植被建设适宜的盖度范围，为该地区荒漠化治理提供理论基础。本文的主要结论包括：1.在整个生长季（4—10月），不同植被盖度的沙丘土壤含水量受地势影响变化趋势整体一致。土壤含水量从沙丘顶部到中部波动增加，从沙丘中部到底部大幅度上升，平均土壤含水量是底部＞中部＞顶部。根据土壤水分变化规律，将沙丘土壤在垂直剖面（0—200 cm）上划分为 3个土壤层：表层敏感层（0—20 cm），根系吸水层（20—140 cm）和深部稳定层（140—200 cm）。根据沙丘土壤水分的季节变化规律划分为干季（4—6 月）和湿季（7—10 月）。湿季土壤含水量大于干季，降水降低了土壤水分异质性。2.在实验期间（6—8月），随着地下水埋深的增加，裸地蒸发量呈下降趋势，蒸发量与降雨量比值和地下水补给量与蒸发量的比值均逐渐减小。地下水埋深分别是61 cm，71 cm，121 cm，131 cm，180 cm和191 cm的土壤，累积蒸发量分别占降雨量的134%，122%，71%，57%，55%和55%，累积地下水补给量分别占累积蒸发量的21%，21%，14%，12%，4%和1%。当地下水埋深大于239 cm，理论上土壤水分供应蒸发较弱。整个生长季节，流动沙丘在0—200 cm土壤深度蓄水量增加19 mm，渗漏量为95 mm。沙丘对丘间地补给水量为16 mm。3.植被盖度与土壤含水量呈负相关的趋势。随着植被盖度的增加，土壤含水量低于1.55%的土壤深度范围增加，持续时间延长。在沙丘顶部、中部和底部，植被盖度分别超过0.46、0.52和0.71时，土壤处于严重干旱状态，植物生存受到威胁。 关键词：科尔沁沙丘，HYDRUS模型，水分运移，土壤蒸发，植被盖度 |
| 英文摘要 | Soil moisture is the main limiting factor for plant growth in arid and semi-arid areas. Vegetation construction as effective measures to control desertification. In the process of long-term sand control, artificial vegetation construction method with large area sand dune has been widely adopted, and remarkable sand fixing effect has been obtained. However, it has adverse effects on its water balance process, resulting in the water imbalance in the sand dune system, after the construction of artificial vegetation, the flow sand dunes were transformed into fixed sand dunes, which increased the coverage of the surface vegetation on the sand dunes, changed the surface morphology, increased the water consumption and increased the loss of soil moisture in the sand dunes, which would have an impact on the long-term stability of sand fixing vegetation and reduce the effect of sand fixation.In this paper, the characteristics of vegetation, soil moisture and geomorphology of ten sand dunes with different vegetation coverage were investigated and observed in Horqin sandy land, and the seasonal dynamics and spatial distribution of soil moisture in the sand dunes were analyzed. At the same time, the HYDRUS model was used to study the soil water movement and the response of soil evaporation to groundwater in the mobile dunes. Through the comparison and analysis of the relationship between soil moisture and vegetation coverage, the suitable coverage range of sand dune vegetation construction in Horqin sandy land is proposed, which provides a theoretical basis for desertification control in this area. The main conclusions were as follows:1. In the growing season (April to October), the soil water content of sand dune with different vegetation coverage is consistent with the change trend of topography influence. And the trend of fluctuation increased from the top to the middle of sand dune, then there was a significant upward trend from the middle to the bottom, and the average soil water content was at the top of bottom, and the average soil moisture is at the bottom of the top > middle > bottom. According to the regularity of soil moisture change, the soil of sand dune (0—200 cm) were divided into 3 soil layers on the vertical profile of soil.: the surface sensitive layer (0—20 cm), the root water absorbing layer (20—140 cm) and the deep stable layer (140—200 cm). According to the seasonal variation of soil moisture in sand dune, it is divided into dry season (April to June) and wet season (July to October). The wet season soil moisture is greater than the dry season, and precipitation reduced soil moisture heterogeneity.2. During the experiment period (June to August), with the increase of groundwater depth, the evaporation of bare land is decreasing. And the ratio of evaporation to rainfall and groundwater recharge to evaporation decreased gradually. The groundwater depth is 61 cm, 71 cm, 121 cm, 131 cm, 180 cm and 191 cm of the sand dunes, cumulative evaporation accounted for 134%, 122%, 71%, 57%, 55% and 55% of rainfall respectively, and cumulative groundwater recharge 21%,14%,12%,4% and 1% of cumulative evaporation capacity respectively. And the soil evaporation is not affected by of groundwater when the groundwater depth was deeper than 239 cm. In the whole growing season, the soil water storage in 0—200 cm soil depth of in the moible sand dune increased 19mm, and the amount of seepage was 95mm. The water supply of sand dune to the interdune is 16mm.3. There was a negative correlation between vegetation coverage and soil water content. With the increase of average vegetation coverage, the soil depth range of soil water content was less than 1.55%, the time was prolonged. At the top, middle and bottom of the sand dunes, and the soil was drought stress when the vegetation coverage is more than 0.46, 0.52 and 0.71 respectively, which is not suitable for the survival of the vegetation. Key words: Horqin sand dune，HYDRUS model，water migration，soil evaporation， vegetation coverage |
| 中文关键词 | 科尔沁沙丘 ; HYDRUS模型 ; 水分运移 ; 土壤蒸发 ; 植被盖度 |
| 英文关键词 | Horqin sand dune，HYDRUS model，water migration，soil evaporation， vegetation coverage |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院沈阳应用生态研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288107 |
| 推荐引用方式 GB/T 7714 | 杨婷婷. 科尔沁沙地沙丘土壤水分运移与水分特征研究[D]. 中国科学院大学,2018. |
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