引黄春灌对盐碱土区地下水动态及理化性质的影响

目的]探究引黄春灌对区域浅层地下水动态及地下水理化性质的影响.方法]通过监测试验区盐碱地春灌前后地下水位、八大离子(Na+、K+、Ca2+、Mg2+、HCO3-、Cl-、SO42-、CO32-)质量浓度、地下水EC值、pH值、土壤电导率等指标,运用数理统计和水文地球化学分析的方法,分析春灌前后地下水动态及春灌后地下...

The Changes in Depth and Physicochemical Properties of Groundwater in Response to Spring Irrigation in Hetao Irrigation District

【Objective】Irrigation in Hetao Irrigation District relies on water diverted from the Yellow River,and it has a direct consequence for physicochemical properties of both soil and groundwater.The purpose of this paper is to study the impact of spring irrigation on depth and physicochemical properties of the groundwater.【Method】The experiment was conducted on a saline-alkali soil.We measured the changes in groundwater table,typical cation and anion ions,EC,pH,and other factors in the groundwater before and after the spring irrigation.The impacts of the irrigation on changes in groundwater depth and its physicochemical properties were analyzed using statistical methods.【Result】The irrigation increased the concentrations of TDS,Ca²⁺,K⁺+Na⁺,SO₄^2-and Cl^-,especially K⁺+Na⁺+and Cl^-which not only had the largest coefficient of variation but also varied most erratically over space.Along with rock weathering and evaporation crystallization,cation exchange was another factor that modulated the change in chemical composition of the groundwater.After the irrigation,chemical composition of the groundwater shifted from Na-Mg-Cl^-SO₄-HCO₃ type and Na-Cl^-SO₄-HCO₃ to Na-Cl^-SO₄ type.Depending on irrigation amount and region,it took 10~20 day for the groundwater to respond to the irrigation,with the groundwater table rising by 1.197~2.142 m at a daily rate 0.0798~0.169 m/d.【Conclusion】Spring irrigation increased the average TDS content of grounded by 15.6%,indicating a salt leaching,but it also raised the groundwater table giving rise to soil salinity.Therefore,to alleviate soil salinization,spring irrigation amount should be reduced,and drainage system should be improved in the region.