徐淮地区花碱土类型与地下水的关系及类型演变

Evolution of Patch Alkali Soil Types in the Xuhuai District in Connection with Groundwater

徐淮地区花减土共同发育在黄泛冲积母质上,包括盐化、碱化和盐碱化黄潮土３个类型。盐分下降过程中,Ｎａ＋、Ｃｌ－、ＳＯ＿４￣（２－）含量和ＳＡＲ显著下降,Ｃａ％、（ＨＣＯ＿３＋ＣＯ＿３）％基本增加,土壤盐渍类型由Ｎａ－Ｃｌ·ＳＯ＿４或Ｎａ－ＳＯ４·Ｃｌ到Ｎａ－ＨＣＯ３·Ｃｌ·ＳＯ＿４再到Ｃａ－ＨＣＯ＿３,花减土类型转化可能为盐化或盐碱化黄潮土至碱化黄潮土,最终为非盐碱化黄潮土。ｐＨ值与盐分非直接相关而与ＲＳＣ和总碱度呈正相关。地下水矿化度减少过程中,Ｃｌ－、Ｎａ＋含量和ＳＡＲ下降,而Ｃａ％、（ＨＣＯ＿３＋ＣＯ＿３）％增加,水化学类型由Ｎａ·Ｍｇ－Ｃｌ·ＨＣＯ＿３至Ｎａ·Ｍｇ·Ｃａ－ＨＣＯ＿３再到Ｃａ－ＨＣＯ＿３。地表积盐程度与地下水矿化度非直接相关,但地表盐渍类型与地下水化学类型有一定联系,在Ｎａ·Ｍｇ－Ｃｌ·ＨＣＯ＿３型地下水上,仅发育盐化黄潮土,而在Ｎａ·Ｍｇ－ＨＣＯ＿３·Ｃｌ型地下水上,３种类型花碱土均有可能出现。

The patch alkali soils (PAS) in the Xuhuai district of jiangsu Province have developedupon the loess alluvial deposit,including three types,i.e,salinized yellow fluvo-aquic soil(SYFAS),alkalized yellow fluvo-aquic soil(AYFAS),and slksli-salinized yellow fluvo-aquic soil (ASYFAS).The salt and alkali of the PAS are centered at the surface soil layer and distributed sporadically,and the saline-alkali properties are complicated.There exists some connection between each of the three types of PAS.Forty samples of surface PAS.and 40 samples of corresponding groundwater were collected.The development of the types of PAS and groundwater and the relationships between the PAS types and their groundwater were analysed.The results are as follows.① The Na+,Cl-,SO4(2-)contents and SAR decreased significantly while Ca% and(HCO3+CO3)% increased generally during the desalinization Process.The salinization type varied from Na-Cl·SO4·Cl or Na-SO4·Cl to Na-HCO3·Cl·SO4 toCa-HCO3,consequently, the development of the PAS might be from SYFAS or ASYFAS to AYFAS,and finally to non-ASYFAS.The pH value was correlated with RSC andtotal alkalinity,and indirectly correlated with salt content.② The Cl- and Na+ contents and SAR fell while Ca% and(HCO3+CO3)% rose during the groundwater dilution Process,and the hydro-chemical type changed from Na·Mg-Cl·HCO3 to Na·Mg·Ca-HCO3 to Ca·HCO3 ③ The salinity of the surface soil did not directly correlated to the mineralization degree of groundwater,while the saline chemistry type was related to the hydro-chemistry type to some extent. Only SYFAS grew on the groundwater of Na·Mg-Cl·HCO3,and all of thethree types of PAS could occur upon the groundwater of Na·Mg-HCO3·Cl.