【摘要】 传统的沙地治理上,忽略了沙丘的环境资源的作用,往往把沙丘作为治理对象,利用各种措施把其拉平。沙丘是风作用于流沙的结果,沙丘形成后,成为风障,使风的强度下降,方向改变,这不仅使风的剥蚀作用下降,甚至消失;而且气流携带流沙的能力下降,流沙在沙丘的下风向下降沉积,沙丘增大,阻沙作用增强(正反馈作用)。所以说沙丘是风制风障、沙成沙阻,是沙区防风固沙的重要资源。沙丘还改变地表的小气候,使热量,温度及蒸散条件发生分异,为植被的多样性创造了条件,沙丘的阴坡比地带偏冷润,阳坡比地带偏干热,这是沙地非地带性植被形成及植物非地带性分布的根本原因。调查发现浑善达克沙地东段,维持乔灌木生存的水分主要来源于2m左右的土层,所以这些乔灌木能在草原地区生存主要是沙丘为其提供了逃避干旱胁迫的条件。因此沙丘是很好的环境资源条件。更多还原

【Abstract】 The classic method of sand land management does not treat the sand dune as a resource of environment,but tread it as the target of harness and bring it to the same level as around by means.Sand dune is the result of wind on drift sand.The formed sand dune is a windbreak;it decreases the intensity of wind and change the direction of wind.This leads to not only a decrease of erosion effect by wind,but also a decrease of the capacity of carrying sand by the wind.The drift sand falls down on the sand dune,and enlarges the sand dune,then increase the action of sand dune to stop the drift sand(positive feed back effect).So the sand dune is a windbreak made by wind,and a obstruction of drift sand made from drift sand.The sand dune is an important windbreak and sand-fixation resource of the sand land.The sand dune also can change microclimate of the sand land,and differentiate the heat quantity,temperature and the evapotransporation condition,form a condition for the biodiversity of vegetation.The dark slope of the sand dune is more moisture and lower temperature,and the sunny slope is higher temperature and drier than the zonal climate.This is the true reason why azonal vegetation forming in the sand land and some azonal plants distribute in the sand land.Investigation shows that the water for some trees is mainly from the soil of 2m layer,thus the dark slope of sand dune gives a more cool and moisture environment for the trees in the grassland region Therefore sand dune is an excellent environment resources on the sand land.更多还原