古尔班通古特沙漠工程防护体系内土壤水分变化规律

Soil Moisture Distribution in Straw Barrier System in Gurbantonggute Desert of Xingjiang,China

古尔班通古特沙漠位于准噶尔盆地腹地,是我国最大的固定与半固定沙漠。近年来在沙漠腹地进行的一系列工程建设项目,不可避免地造成对地表的扰动,并直接影响土壤水分状况。通过对工程防护体系内典型部位和原始沙面的土壤水分进行系统监测,得到土壤水分变化规律。研究结果表明,工程防护体系内土壤含水率整体高于原始沙面的土壤水分。土壤水分含量的季节变化表现为3～4月的补给期、5～7月的失水期、8～10月的弱失水期和11～2月的冻结滞水期。其垂直分布可分为表层30cm的活跃层、30～60cm的过渡层和60cm以下的稳定层。防护体系内坡向和坡度对土壤水分有显著的影响,阴坡明显高于阳坡,陡坡又低于缓坡。

The Gurbantonggute Desert, located in Junggar Basin in north Xinjiang, with an area of 48 000 km2, is the second largest desert in China. It is comprised mainly of fixed and semifixed longitudinal dunes. In recent years, many linear engineering projects have been constructed across the longitudinal dunes. This has disturbed the sand surface and affected soil moisture directly. In this study we measured the moisture at the typical soil profile, and some results are concluded. From the top to the bottom there exist 3 distinctive layers of soil moisture, namely upper active soil moisture layer (0~30 cm), middle medium soil moisture layer(30~60 cm) and lower stable soil moisture layer(60~10 cm). Based on the seasonal variation of sandy soil moisture, it can be divided into 4 phrases: the soil moisture is increased in early spring, lost in summer and autumn and stable in winter. The soil moisture in straw barrier system is higher than the natural land for biocrust and ephemeral plant play an important role in redistribution of soil water. Slopward direction to the soil moisture is also discussed.