沙坡头地区吸湿凝结水对生物土壤结皮的生态作用

Ecological effect of hygroscopic and condensate water on biological soil crusts in Shapotou region of China

以沙坡头植被固沙区为研究对象,采用野外试验与室内分析相结合的方法,探讨了吸湿凝结水对生物土壤结皮的生态作用.结果表明:在沙坡头人工固沙植被区内,吸湿凝结水90%分布在表层3cm以内,不影响土壤表层水分含量;夜间形成的吸湿凝结水在日间参与了地表水分与大气层水汽的交换过程,弥补了日间蒸发作用导致的土壤水分的散失,使表层土壤水分不会迅速降低.吸湿凝结水形成量与生物土壤结皮中的叶绿素含量呈正相关关系,能够提高该区生物土壤结皮的生长活性,有利于其生物量的积累.

By the method of field experiment combined with laboratory analysis, this paper studied the ecological significance of hygroscopic and condensate water on the biological soil crusts in the vegetation sand-fixing area in Shapotou region of China. In the study area, 90% of hygroscopic and condensate water was within the 3 cm soil depth, which didn＇ t affect the surface soil water content. The hygroscopic and condensate water generated at night involved in the exchange process of soil surface water and atmosphere water vapor, made up the loss of soil water due to the evaporation during the day, and made the surface soil water not reduced rapidly. The amount of the generated hygroscopic and condensate water had a positive correlation with the chlorophyll content of biological soil crusts, indicating that the hygroscopic and condensate water could improve the growth activity ofthe biological soil crusts, and thus, benefit the biomass accumulation of the crusts.