荒漠地区柽柳人工固沙林土壤水分动态研究

柽柳林土壤剖面的含水量与裸沙地土壤含水量的变化趋势有相似性，表层（0－30cm)含水量均受蒸发量和降雨量的影响变化较大，由于树冠的遮荫作用林地该层平均含水量高于裸沙地的含水量，30－200cm范围内林地土壤的各测量层平均含水量较裸沙地的低，林地和裸沙地土壤含水量均值随深度的变化可用二次函数描述；降雨对每月的0－200cm的土壤水量没有明显的影响，说明降雨多数在当月就被蒸散和深层渗漏所消耗；发现柽柳人工固沙林能在沙土壤的0－200cm范围内有较低的含水量条件下生存。

Soil water regime of Tamarix ramosissima sandbreak in the desert region

The distribution of soil water content in the shrub sand land a nd bare sand soil was measured.The water content of both bare soil and shrub land increased as the depth of soil profile increased.The soil water content of shrub land was higher than that of bare soil in soil depth of 0~30 cm because of shade of shrub canopy,which was significantly affected by rainfall and evaporation.The soil water content of shrub land was lower than that of bare soil in soil depth of 30~200 cm.The relationship between the average values of water contents and their depths of measured soil layers can be described by a quadric function.The rainfall did not significantly influenced the soil water storage of stand in 0~200 cm,which means that the most rainfall of a month was completely consumed by evapotranspiration and seepage at the same time.We suggest that the redistribution of soil water and groundwater by tree root systems is the one of important factors that affects the survival of Tamarix ramosissima from severe environmental conditions.