土壤盐化过程中阳离子对镉的形态分布影响

Impact of inorganic cations on cadmium fractions in the alkaline saline soils

以硝酸盐为例,实验分析了无机盐阳离子对碱性盐化土壤中镉形态分布的影响。结果表明,随着Na+、K+、Ca2+、Mg2+等阳离子进入土壤,土壤中镉的有效态含量增加,对镉有明显的活化作用;随着Na+、K+、Ca2+、Mg2+浓度的增加,有效态镉的含量进一步增加,镉有效态的增加幅度可达到55.46%～68.39%;土壤镉的其它各形态含量都随着Na+、K+、Ca2+、Mg2+等的加入而减少,其中碳酸盐态的减少量为23.61%～63.14%,铁锰氧化态的减少量为10.77%～25.66%,有机态的减少量为18.11%～54.68%,残渣态的减少量为2.14%～12.78%。不同种类阳离子对土壤中镉形态变化的影响程度有差异,钙离子对土壤中镉的吸附竞争能力最强,镁离子次之,而钠离子和钾离子对镉的吸附竞争能力相似。

The impact of inorganic cations on cadmium fractions in in the alkaline saline soils was studied by experiment.The result showed that cadmium effective fraction content in the soil increased with the addition of Na＋,K＋,Ca2＋and Mg2＋,meaning that the the soil absorption to cadmium reduced and cadmium occurred activations.The cadmium effective fraction content further increased with the increase of Na＋,K＋,Ca2＋and Mg2＋ concentrations in soil solution,and the increased rate could reach about 55.46%～68.39%.The concentrations of the other cadmium fractions reduced with the addition of the cations,and the carbonate fraction concentration reduced about 23.61%～63.14%,Fe-Mn oxidation bound concentration reduced about 10.77%～25.66%,organic bound concentration reduced about 18.11%～54.68% and residual fraction reduced about 2.14%～12.78%.The impact of the cation types on cadmium fractions was different;Ca2＋ had the strongest adsorption competitiveness with cadmium in the soil,followed by Mg2＋,and the adsorption competitiveness of Na＋and K＋with cadmium was similar.