四川山丘区不同利用方式土壤磷吸附特性

Phosphorus Adsorption Characteristics of Soils under Different Utilization Ways in Sichuan Hilly Area

[目的]研究四川山丘区11种不同利用方式土壤磷的吸附特性,为生态沟渠底质的选择提供科学依据。[方法]针对生态沟渠中的底质,选取四川山丘区11种不同利用方式的土壤为研究对象,对磷的吸附特性进行研究。[结果]等温吸附时,磷的最大吸附量Qm、吸附平衡常数K、最大缓冲容量MBC均与黏粉粒含量呈正相关,但K和MBC与p H呈负相关;适宜的淹水条件能增加土壤黏粉粒含量,促进非晶质氧化铁的形成,从而有利于土壤对磷的吸附。土壤磷吸附动力学试验表明,在接触时间2 h内吸附反应速率较快,这是磷向沟渠底质转移的主要阶段;去除水体中多余的磷素,应选取黏粉粒含量高的土壤作为生态沟渠的底质。[结论]该研究对生态沟渠底质的合理选择具有重要的实际应用价值。

[ Objective ] To study phosphorus adsorption characteristics of soils under different utilization ways in Sichuan hilly area, in order to provide scientific basis for the selection of ecological ditch substrate. [ Method ] Eleven kinds of soils with different utilization ways in Sichuan hilly area were chosen,and experimental research on the phosphorus adsorption characteristics was done. [ Result] During isothermal adsorp- tion, positive correlation existed between the maximum adsorption capacity Qm, adsorption equilibrium constant K, maximum buffer capacity MBC of phosphorus and clay, silt contents, but negative correlation existed between K, MBC and pH;Suitable flooding condition could in- crease the clay and silt contents of soil, promoted the formation of amorphous iron oxide and was suitable for the adsorption of soil for phosphor- us ; Experiment of soil phosphorus adsorption kinetics had shown that the adsorption reaction was rapid within 2 h of contact time, which was the main stage of phosphorus transferring to ditch substrate ; Soil with high contents of clay and silt should be chosen as the substrate of ecologi- cal ditch to remove the extra phosphorus in water. [ Conclusion] The research results have important practical application value for the reasona- ble selection of ecological ditch substrate.