在实验室条件下对两种水稻土在为期 6周的淹水过程中 ,其氧化层和还原层土壤中还原物质总量 (TRS)、草酸盐可提取铁 (Feo)、连二亚硫酸钠 -柠檬酸 -碳酸氢钠可提取铁 (Fe DCB)和磷吸附的变化进行了研究 .结果表明 :淹水可急剧增加新鲜土样中的 TRS、Feo 和土壤对磷的吸附 ,并且还原层土壤的TRS、Feo 和土壤对磷的吸附明显高于氧化层土壤 .TRS、Feo 和磷吸附之间存在着极显著的相关关系 ,表明淹水过程中土壤 Eh的下降、致使 Fe DCB向结晶度差的 Feo 转化是导致土壤对磷吸附显著增加的主要原因 During the 6-week flooding of paddy soils under laboratory conditions, the contents of total reducing substances (TRS), oxalate-extractable iron (Feo), sodium dithionite- Citric acid-sodium bicarbonate (Fe DCB) and the change of phosphorus adsorption were studied.The results showed that flooding could dramatically increase the adsorption of phosphorus by TRS, Feo and soil in fresh soil samples, and the reduction layer soil The adsorption of phosphorus on TRS, Feo and soil was significantly higher than that on oxide soil. There was a significant correlation between TRS, Feo and P adsorption, indicating that the decrease of soil Eh during flooding led to the decrease of Fe DCB to poor crystallinity Feo conversion is the main reason for the significant increase of soil P uptake