沙坡头人工植被区微生物结皮对地表蒸发影响的试验研究

Effect of Microbiotic Crust on Evaporation Process in Vegetated Area in Shapotou Region

微生物结皮是干旱半干旱地区生态系统的重要组成部分,其生态水文过程受到了广泛关注,但对微生物结皮在地表蒸发过程中的作用存在较大的争议。笔者利用微型Lysimeter对沙坡头地区几种典型微生物结皮和流沙地表的蒸发过程进行了试验观测,并与水面蒸发进行了对比分析。结果表明,结皮和流沙地表的蒸发速率随时间的变化趋势基本相同,但在不同的蒸发阶段具有各自不同的特点,总的说来,发育良好的苔藓结皮导致相对较少的无效降水,但在更长的时间维持较高的蒸发速率;流沙和初步发育的降尘结皮导致了较多的无效降水,但由于降水的入渗深度相对较深,需要更长的时间完成蒸发过程。

Microbiotic crust is one of the important components in arid and semi-arid area, which attracts more and more attentions for its hydrological process recently. In this paper, evaporation process of the typical microbiotic crust is studied by using micro-Lysimeter in vegetated area in Shapotou region. The result shows that well developed microbiotic crust results in less invalidation precipitation than sandy soil, but sandy soil conserves 18% precipitation in deeper layer when the soil covered with microbiotic crust had been dry completely.