『Abstract
　The high phosphorus levels cause the release of phosphorus from soils, thereby increasing the potential for phosphorus export to adjacent water bodies. The loss of phosphorus from soils to surface waters is a major source of water quality impairment. Therefore, soil phosphorus immobilization seems necessary. In this study, red mud (RM) was employed to immobilize phosphorus in a typical agricultural soil. It was found that phosphorus was effectively immobilized by RM. Batch leaching experiments showed that RM reduced phosphorus release from 14.38 to 2.56 mg/kg when soil was amended with 1% RM. Column leaching experiments showed that RM reduced the total amount of phosphorus released from 36.73 to 18.70 mg/kg during the investigated period. Sequential chemical extraction results indicated that RM amendment transformed H2O-P into more stable fractions. The results suggested that application of RM amendment to soils could significantly immobilize soluble phosphorus, reducing phosphorus release to the environment.

Keywords: Red mud; Immobilization; Phosphorus; Clay soil; Release』

Introduction
Materials and methods
　Materials
　Adsorption isotherm investigation methods
　Incubation methods
　Leaching investigation methods
　Analytical methods
Results and discussion
　Soil characteristics
　Adsorption isotherm for phosphorus
　Batch leaching experiments
　Column leaching test
　Effect of RM immobilization on soil phosphorus speciation
Conclusions
Acknowledgments
References