关键词: 生态安全, 地下水动态, 作物, 绿洲, 民勤县, 石羊河

Abstract: Based on the technology of GIS and RS, status and formation cause of ecological security of Minqin Oasis in Shiyanghe river basin was studied. The following results have been got. The increasing probability of soil encroached by wind and sand has decreased the security of soil. Depth of groundwater descended constantly and the area percent of groundwater depth between 5~20 m increased to 62.1% in 2001 from 39.6% in 1987. The groundwater mineralization in northern oasis increased. The area percent of wheat and cotton in growth safety separately decreased to 56.2%, 71.3% in 2001 from 63.8%, 91.5% in 1987. The ecological defense system that made up of forest and sparse grassland was destroyed. The decrease of surface water resource was the main reason of ecological security deterioration, and the unreasonable land use has ac celerated the degradation of ecological environment.

Key words: ecological security, groundwater dynamics, crop, oasis, Minqin, Shiyanghe river basin