古尔班通古特沙漠地表土壤凝结水形成影响因素分析*

沙漠中水分条件是决定生态分异的关键因素,地表凝结水的产生对沙漠植物与结皮生物的水分补充有重要的作用。利用微渗计对古尔班通古特沙漠土壤表层凝结水形成特征及影响因素进行分析。研究表明沙漠土壤凝结水形成总量随着表层土壤生物演替从流沙、藻类、地衣和苔藓依次增加。分析影响凝结水形成的因素表明土壤中细粒物质以及地衣和苔藓生物相对土壤粗粒物质更有利于凝结水形成。在土壤结皮演替过程中土壤中的细粒颗粒含量增加的同时生物有机体含量也在增加,因而随着表层土壤生物演替凝结水形成量呈增加趋势。凝结水形成量与日均相对湿度、土壤湿度呈显著正相关,而与日均风速、日均温度、土壤温度呈负相关。研究说明在干旱的沙漠地带土壤凝结水是除降水以外补充表层土壤水分重要的水分来源。

The analyze of factors that effect on the total amount of condensation water formation on topsoil in the Gurbantunggunt Desert

Water condition are the key factor to ecological conditions in desert area, in such area the condensation water produced in soil surface serves as an important source for plants and biological soil crusts(BSC). Through measuring condensation water formation on successional BSC in the Gurbantunggunt Desert with micro-lysimeter, and we analyze the factors that effect the amount of condensation water. The total amount of condensation water increased with the succession of BSC (sand, cyanobacterial crust, lichen crust and moss crust respectively). The more proportion of silt, clay and living organisms such as lichen and moss in the latter successional BSC lead the more of condensation water and direct water vapor adsorption. The air humidity and soil moisture have positive effect on amount condensed water of soil. The wind speed, air and soil temperature have negative effect on amount of condensed water. The results suggested that, besides precipitation, the condensation water play a vital role in providing an essential source of water for surface soil in arid and semi-arid areas.