关键词: 生态环境效应, 土壤水盐分异, 黑河中游, 张掖绿洲

Abstract: The soil moisture and salt contents analysis for representative oases in the middle reaches of Heihe River presented in this paper shows that the horizontal diversity of topsoil moisture content in oasis-desert belt is distinct under no irrigation condition, that is, the topsoil moisture content reduces from 20% of oasis to 2.9% of oasis-desert ecotone. The change of soil moisture content in oasis-desert belt reflects the utilization degree of water resources. Where is over extracting of groundwater and human intensive activities where exists \!ecological gap\", which is disadvantageous to the stabilization of oasis ecosystem. The horizontal variance of soil dissoluble salt contents indicates that salt contents in oasis soil are lower than that in ecotone soil and desert soil. Besides, the soil salt contents are different in desert types outside oasis, that is, the soil salt content in sandy desert is lower than that in the Gobi. The vertical profiles of desert soil salt content indicate that the higher salt content is not in the surface layer but in the subsurface layer of 40～60 cm. The soil moisture and salt content variances have resulted in the deserta diversity outside oasis, the drought-tolerance and salt-tolerance of deserta increase gradually from oasis in higher place to oasis in mid-position.

Key words: oasis, eco-environmental effects, soil moisture and salt contents