【作者】 杨婧；

【导师】 胡春元；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2010， 硕士

【摘要】 沙地榆是榆科榆属白榆的一个变种,天然分布于内蒙古自治区中东部浑善达克、乌珠穆沁、科尔沁等沙地中,适生性强,在维持沙地生态系统多样性和沙稳定性方面具有非常重要的作用。但是,最近几十年沙地榆分布面积锐减,密度下降,更主要的是出现了幼苗减少等问题,说明沙地榆的天然更新出现了问题。为了更好地保护、利用这一重要资源,恢复沙地榆自然更新过程,我们研究了沙地榆分布与气候条件的关系,及与地下水埋深、地下水水质的关系。作者首先收集了邻近四个气象站48年的气象资料,采用内插法计算了沙地榆分布中心区、东端白桦替代区、西端消失区的气温和降水量,分析了沙地榆分布与气候因子的关系;又于2008年和2009年夏秋之际,以桑根达来为中心,自北向南、自西向东设定长度100km左右的两条样带,采用样线结合样方法调查了沙地榆分布密度及生长状况;通过开挖剖面测量了潜水埋深,同时提取水样并在实验室完成水质分析,完成了大尺度范围内沙地榆分布与潜水埋深、水质关系的研究;之后,在桑跟达来附近选定一个典型观测点,垂直沙丘走向设置了三条观测样带,详细测量了地形及高程,绘制了地形示意图、沙地榆生长状况图、潜水等水位线图,从小尺度上研究了沙地榆分布与潜水埋深、水质的关系。结果显示:(1)在浑善达克沙地,沙地榆集中分布区多年平均气温在2.2℃左右,多年平均降水量在330-360mm,但这一数值与周边没有沙地榆分布地区的气候条件没有显著差异,因此认为在沙地榆分布范围内,降水与温度不是影响沙地榆分布的主要因素。(2)潜水水质与沙地榆的分布没有明显的相关性,而潜水埋深是影响沙地榆分布的重要因素。沙地榆主要是依靠大气降水及土壤水而不是地下水而生存;当潜水埋深小于1.7-1.8m时,地面不会出现沙地榆,我们把这个水位称为沙地榆生长的限制水位,因此,在浑善达克沙地营造榆树疏林时不可选择潜水埋深小于1.8m的丘间低地。更多还原

【Abstract】 Ulmus pumila L.var.sabulosa is a variant of the Ulmus pumila, which distributed in central and eastern Inner Mongolia Autonomous Region, such as Otingdag sand land, Ujimqin, Mongolian and other sands. It is so strong that it plays a very important role in maintaining the diversity of ecosystem and in desert management program . However, in recent decades dropped Ulmus pumila distribution area, the density decreased, growth recession, more is the emergence of seedling drop, shows natural regeneration of Ulmus pumila problems.In order to better protect the use of this important ecosystem and biological resources, Ulmus pumila to restore the natural renewal process, first need to figure out the growth of Ulmus pumila in terms of environment and natural regeneration, in which the distribution of climate and Ulmus pumila the relationship between the conditions, Ulmus pumila distribution and groundwater level, groundwater quality of the relationship is important. At the first, near 48 years of weather data were collected in four stations, calculated by interpolation of Ulmus pumila distribution center, the eastern end of Birch replacement area, the western end of the temperature and precipitation away zone, analysis of distribution of Ulmus pumila climatic factors; again in 2008 and 2009 summer and fall to the mulberry roots reach to the center, from north to south, from west to east about 100km to set the length of the two transects, transect investigated the combination of sampling methods Ulmus pumila density and growth conditions; excavation profiles measured by the depth of water, while water samples and water quality analysis in the laboratory, completed a large-scale distribution within the Ulmus pumila diving depth, diving and water relations research; later, in the vicinity of Mulberry with up to a typical observation point selected, set perpendicular to the three observed dune transect, detailed measurements of the topography and elevation, schematic drawing of the terrain, Ulmus pumila growth status map, diving and other water level maps, small scale distribution of the Ulmus pumila and diving depth, water quality in the relationship.The results showed:(1) In the Otingdag sand land, suitable Ulmus pumila climate conditions for the growth of annual average temperature is 2.2℃and the mean annual precipitation is about 330-360mm. But there was no significant difference between the figure and the climate of the surrounding areas, precipitation and temperature are not the major factors affecting the distribution of Ulmus pumila.(2) Water quality and the distribution Ulmus pumila have no obvious correlation while the depth of water is an important factor in the distribution of Ulmus pumila. When the diving depth of more than 1.7-1.8m, while the deep of water can not affect the Ulmus pumila distribution, and its growing . Even in high sand dunes over 20m (At the base of Ulmus pumila the distance between surface and diving to 22m or so), Ulmus pumila still be able to grow normally, not only the larger diving depth of the Ulmus pumila no direct impact, said Ulmus pumila mainly by precipitation and sand stored in the free water or condensation water rather than groundwater for its survival; when the diving depth of less than 1.7-1.8m, the ground will not be Ulmus pumila, we called Ulmus pumila this level of growth of water level, reason may be the Groundwater high Ulmus pumila root cause abnormal growth or decay can not be caused, therefore, to create a Ulmus pumila in Otingdag sand land must not choose the depth of water less than 1.8m of the lowland.更多还原