在盐碱土的水浸提液中,经常要测定的盐分组成是Ca~(++)、Mg~(++)、Na~+、K~+四种阳离子和CO_3~-、HCO_3~-3、CI~-、SO_4~-四种阴离子,有时也测定NO_3~-。这些离子的分析方法很多,操作手续有简有繁,准确性也不一样。从简单、快速、准确的要求出发,钙镁离子测定以EDTA络合法较好,钠钾离子用火焰光度计法较适 In the salinity - alkaline aqueous extract, the salt composition is often determined as Ca ~ (++), Mg ~ (++), Na ~ +, K ~ + and CO_3 ~ -, HCO_3 ~ 3 , CI ~ -, SO_4 ~ - four kinds of anions, sometimes measured NO_3 ~ -. Many of these ion analysis methods, there are simple procedures, accuracy is not the same. Starting from simple, fast and accurate requirements, the determination of calcium and magnesium ions by EDTA complexation method is better, sodium and potassium ions by flame photometry method is more appropriate