采用无机磷分级方法研究了有机酸对石灰性土壤和红壤无机磷形态转化的影响，结果表明，有机酸对石灰性土壤和红壤无机磷形态有明显的影响。石灰性土壤经柠檬酸和草酸浸提后，其Ｃａ２Ｐ、Ｃａ８Ｐ和ＯＰ的含量增加；而Ｃａ１０Ｐ、ＦｅＰ和Ａ１Ｐ的含量下降。柠檬酸和酒石酸对红壤无机磷的形态也产生明显影响，表现为Ａ１Ｐ含量增加，ＦｅＰ和ＣａＰ含量下降，ＯＰ变化不大。有机酸通过影响土壤中无机磷组分，促进难溶性磷酸盐溶解，从而提高土壤磷的有效性。研究还表明，施磷能明显提高石灰性土壤和红壤无机磷含量。 The effects of organic acids on the transformation of inorganic phosphorus in calcareous soils and red soils were studied by inorganic phosphorus fractionation. The results showed that organic acids had obvious effects on the forms of inorganic phosphorus in calcareous soils and red soils. After calcareous soil was leached by citric acid and oxalic acid, the content of Ca2-P, Ca8-P and O-P increased, but the content of Ca10-P, Fe-P and A1-P decreased. Citric acid and tartaric acid also had a significant effect on the inorganic phosphorus forms in red soil. The results showed that the content of A1P increased, the content of FeP and CaP decreased, while the content of P changed little. Organic acids can improve the availability of soil phosphorus by affecting the inorganic phosphorus components in the soil and promoting the dissolution of insoluble phosphates. The study also shows that phosphorus application can significantly increase the content of inorganic phosphorus in calcareous soils and red soils.