古尔班通古特沙漠南部沙垄水分动态——兼论积雪融化和冻土变化对沙丘水分分异作用

Variation Pattern of Soil Water Content in Longitudinal Dune in the Southern Part of Gurbantünggüt Desert: How SnowMelt and Frozen Soil Change Affect the Soil Moisture

2004年3月至2005年7月对古尔班通古特沙漠南部典型半固定沙垄土壤水分进行了系统监测，结合气象资料，特别是对冬季积雪和冻土资料的分析，认为该沙漠沙丘土壤水分时空变化规律在很大程度上受积雪融化和季节性冻土的影响．由于冬季稳定存在20-30cm的积雪于春季融化，使得春季沙丘土壤含水率成为全年最高的季节，从而为早春植物的萌发生长创造了有利的条件．冬季1m多深的冻土于早春时节由表及里开始消融，沙丘表面融化的雪水在坡面重力作用下，沿难以透水的冻土层上界自坡上向坡下发生迁移，在春夏季形成了垄间最高、坡部次之和垄顶最少的土壤水分空间格局．该研究具有生态学意义，可为古尔班通古特沙漠特殊环境条件下植被恢复与重建提供依据．

Based on the soil moisture on a longitudinal dune measured from March in 2004 to July 2005 and analyzing the weather station data in the southern part of Gurbantunggut Desert, it is found that the spatial and temporal variations of soil moisture are mainly affected by snow melting and frozen soil changing. There is a stable snow cover with a depth of 20-30 cm on the dune surface during winter in the desert, it melts quickly in early spring and supplies water to soil, as a result, the spring becomes the richest season of soil moisture during a whole year. Again, there is a notable frozen soil layer in the desert, which melts from top to bottom in early spring. Under.gravity, melting water moves from the dune crest downwards. Therefore, the soil moisture is high in interdune, medium on slope and little on crest in spring and early summer. This result provides the base for vegetation rehabilitation in desert.