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我国黄河流域中下游及辽河下游一带(北纬34°-42°,东经106°-124°),分布有河流冲积、风积所形成的内陆和沿海沙地。这些沙地的气候特点是:春季多大风,降水量少,年平均降水量150-750毫米;蒸发量较大,年蒸发量1,500-2,500毫米;气候干燥,湿度低,年平均绝对湿度5-10毫巴,年平均相对湿度65-70％。土壤为冲积土、草甸土、砂性淡钙土;土种有细沙土、沙土、沙壤土、沙砾土等交错分布。土壤干旱瘠薄,有机质含量一般小于1％,缺乏氮、磷营养元素。土壤结构疏松,蓄水与保水力差,酸碱度约为8左右。地表温差变化大,增热与散热都快。旱生植物如白茅、菅草、蒿类等生长旺盛。由于沙地自然条件较差,加上造林技术和抚育管理措施没有跟上,杨树人工林一般生
The middle and lower reaches of the Yellow River basin in China and the Liaohe River (latitude 34 ° -42 ° north, longitude 106 ° -124 °), the distribution of river alluvial, aeolian formed inland and coastal sand. The climatic characteristics of these sandy areas are: how strong the spring windy season is, with less precipitation and an annual average rainfall of 150-750 mm; large evaporation with an annual evaporation of 1,500-2,500 mm; dry climate, low humidity and annual average absolute humidity of 5- 10 mbar, annual average relative humidity 65-70%. Soil alluvial soil, meadow soil, sandy loamy soil; soil with fine sand, sand, sandy loam, sand and gravel soil staggered distribution. Soil arid infertility, organic matter content is generally less than 1%, the lack of nitrogen and phosphorus nutrients. Loose soil structure, water and poor water retention, pH is about 8 or so. Large changes in surface temperature, heat and heat are fast. Dry plants such as white grass, Jian grass, Artemisia and other growth. Due to poor natural conditions in the sand, coupled with afforestation techniques and tending management practices did not keep up, poplar plantation general health