黑河下游土壤和地下水盐分特征分析

根据405个土壤样品和101个水样,分析了黑河下游土壤盐分分布规律以及与地形地貌部位、地下水水化学的关系.结果表明:额济纳三角洲地区的土壤具有质地粗、含盐量高、盐分表聚性强的特征,该地区呈现盐碱化和沙漠化严重、可利用土地资源骤减、生态环境恶化的状况.在所有剖面上盐分的分布呈现漏斗型分布,土壤中盐分随地形变化较为复杂,但与地下水化学变化相一致.地下水矿化度普遍比较高,大多数地区的矿化度在800~3000 mg·L^-1之间变化;水化学类型主要有HCO₃·SO₄-Na、Cl·SO₄-Na(Ca)、HCO₃·Cl-Na(Ca)SO₄·Cl-Na和SO₄·Cl-Na(Ca-Mg).地下水矿化度的高低与补给源的距离远近密切相关,在河岸附近的矿化度变化幅度较小;在远离河道地区,随离岸距离的增减而升降,体现了矿化度的高低主要依赖于上游补给水量变化.

Analysis of the Characteristics of Soil and Groundwater Salinity in the Lower Reaches of Heihe River

Using field investigations and chemical analyses (including 405 soil samples and 101 water samples),the evolution of soil salt with groundwater quality and the location change in the lower reaches of Heihe River were made clear.The soil is coarse,and the salt content is high with high surface concentration in Ejin delta.In the study area,land desertification and land salinization is serious,land resources decrease rapidly,and ecosystem environment deteriorates seriously.Soil salinity has a funnel distribution in the vertical section and it became complicated with topography changing;however,its changing trend is similar to the groundwater quality.The salinity of groundwater is usually high,varying from 800 mg·L^-1 to 3000 mg·L^-1.The main water chemical types are HCO₃·SO₄-Na,Cl·SO₄-Na(Ca),HCO₃·Cl-Na(Ca)SO₄·Cl-Na and SO₄·Cl-Na(Ca-Mg).Analyses of the samples from two longitudinal profiles(a-a’ and b-b’) show that the salinity of groundwater is close related with the distance to the river course.The far to the river course is,the high the salinity is,and the vice versa.