为探讨土壤镁质碱化原因，进行模拟试验。结果表明，如果没有碳酸盐存在，单独的Ｃｌ—Ｍｇ型地下水不会使土壤发生镁质碱化。Ｃｌ—Ｍｇ型地下水是通过溶液中Ｍｇ（２＋）与碳酸盐长期作用在土壤中积累了Ｍｇ（ＨＣＯ３）２，从而使土壤产生强碱性反应、高总碱度和高镁质碱化度。Ｃｌ—Ｍｇ型地下水与碳酸盐的共同作用是土壤镁质碱化性状产生和镁质碱化土形成原因之一。 In order to explore the reason of soil magnesium alkalization, a simulation experiment was carried out. The results show that Cl-Mg-type groundwater alone does not cause magnesium alkalisation in the soil without carbonate. Cl-Mg type groundwater accumulates Mg (HCO3) 2 in the soil through long-term action of Mg (2+) and carbonate in solution, resulting in strong alkaline reaction, high total alkalinity and high magnesia alkalinity . The combined action of Cl-Mg type groundwater and carbonate is one of the reasons for the formation of magnesian alkalinity and formation of magnesia-alkalized soils.