Adsorption And Desorption Of Phosphorus By Sediments And Typical Soil From XiTiaoXi Watershed

Based on the sediments from the upsteam of FuShi Reservoir and the topical soil taken from the XiTiaoXi watershed,this study investigated the the adsorption and desorption of phosphorus (P) on the soil and sediments with different properties under different initial phosphate concentration, pH of top water and organic matter content of the soil and sediments. The results indicated that:(1) The high phosphorus concentration in the sediments is the resources of phosphorus in water bodies.(2) In comparison with the sediments,the soil had a larger adsorption capacity and a smaller sorption-desorption equilibrium concentration.The maximum adsorption of P on soil was 566.451 mg·kg-1. Therefore,it is important to strength the soil and water conservation and decrease the phosphorus loss from field into water bodies in the eutrophication control.(3) The adsorption and desorption capacity is increasing with the increased phosphorus concertration between soil,sediment and overlying water. (4)The soil and sediments would continue to release phosphorus into the overlying water until the phosphorus concentration reached the sorption-desorption equilibrium concentration. So we should focus on reducing the phosphorus concentration of the soil and sediment in water pollution control.(5)There was a positive correlation between the P adsorption capacity and total Fe,amorphous Fe,OM,Fe/Al—P contens.(6)There was a remarkable influence of pH of the overlying water on P adsorption and desorption. The P adsorption decreased rapidly under pH<3 or pH>9.However, the acidification of the water bodies can increase the phosphorus concentration of the overlying water. (7) The organic matter played an important role in the controlling the process of P adsorption/desorption on soil and sediment.