摘要
地下水与天然植被之间有着复杂的关系,它涉及地下水、土壤、植被等相互之间的动态平衡,而干旱区生物过程微弱,生态系统规模小、稳定性低、地下水的变化会直接影响天然植被的生长发育,与脆弱生态环境的保育有着十分密切的关系,本文针对干旱区这一特殊地域研究其规律,并对有关地下水、土壤含水量、生态地下水埋深的概念和内容做了阐述,从不同角度研究了干旱区地下水与土壤含水量、天然植被、地表荒漠化等关系以及合理地下水埋深的确定进行了总结分析,提出了与合理地下水埋深相关的生态地下水埋深、适宜地下水埋深、最佳地下水埋深、盐渍临界深度、生态警戒地下水埋深等概念,确定地下水与天然植被之间相互作用的结构框架,从生态水文学角度更深层次探讨干旱区地下水与天然植被的关系,为深入研究干旱区生态环境的演变趋势提供依据。
There is a complex relation between groundwater depth and natural vegetation, which involves dynamic balance between groundwater depth, soil and vegetation in arid area. The biological process is not obvious and the scale of ecological system is small and unsteady in arid zone. The change of groundwater depth influences directly the growth of vegetation and is closely related to the protection and development of fragile ecological environment. This paper studies the relation between groundwater depth and natural vegetation in the arid zone. The concepts and contents concerning groundwater, soil moisture and ecological groundwater depth are defined. The relation between groundwater and soil moisture, natural vegetation and surface desertification and identification of rational groundwater depth in arid area is summarized from several aspects. The structure frame of interaction between ground water and natural vegetation is established to provide theoretical ground for further research of evolution trend of ecological environment in arid area. On the basis of thorough analysis of relation between groundwater depth and natural vegetation, the concepts of ecological groundwater depth, appropriate groundwater depth, rational groundwater depth, critical depth for salination and ecological-warning depth of groundwater are put forward. The depth of groundwater within one meter is defined as swamp groundwater depth, the depth of groundwater ranged from one meter to two meters as critical groundwater depth for salination, the depth of groundwater ranged from two meters to four meters as appropriate groundwater depth, the depth of groundwater ranged from four to six meters as ecological-warning depth of groundwater, the depth higher than six meters as desertification depth of groundwater. The vegetation grows exuberantly where the groundwater depth is among the range of appropriate groundwater depth. For example, young Populus euphratica are located in such water circumstance, among which the breast diameter can increase 0.5cm～0.6cm per year; the biomass of salt meadow vegetation ranges from 0.44 ton to 1.87 tons per hectare. The living of vegetation is restrained obviously where the arbor and shrub with deep roots have difficulty in utilizing water and grow badly. The appearance frequency of Tamarix spp. is about 6.0 percent and the coverage degree decrease from 0.3 to 0.1 where the groundwater depth is above the range of desertification.
出处
《资源科学》
CSSCI
CSCD
北大核心
2005年第4期160-167,共8页
Resources Science
基金
国家973重点基础研究发展计划项目(编号:2004CB720201)。
