The Investigation About Relationship Between Ulmus Pumila Distributing And Weather & Groungwater In Otingdag Sand Land

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.