【摘要】 沿海农田N、P排放是沿海湿地和近海水质污染源之一。研究围海造田土壤P化学行为对评价其水质污染风险,制定兼顾农业生产和环境保护P肥管理措施具有实际意义。本研究以浙江省慈溪市3个代表性时期(宋代,明代,现代)围海造田水稻田土壤为研究对象,研究了3种温度条件下(15℃,25℃,35℃)土壤P吸附动力学,并获得了其热力学参数。结果表明:①水稻土的P吸附动力学曲线可用Langmuir、Freundlich及Temkin等温吸附方程拟合,而以Freundlich方程的拟合度最高;水稻土壤P吸附热(△H0)分别为4.39,11.40,15.97 kJ/mol,对照前人的研究结果,推测围海造田土壤P吸附作用力是氢键力和偶极间力为主。②土壤最大吸附量(Qm)依次为:宋代>明代>现代土壤,说明,随着种植年限延长,土壤保持P容量增加,土壤固P能力增强。土壤最大吸附量(Qm)与有机质之间呈线性正相关(p<0.01),因此,增施有机肥提高土壤有机质有利于增强土壤P吸附能力。随着温度的上升,土壤最大吸附量逐渐增大,建议选择高温季节使用P肥,可有利于P吸附,降低农田土壤P排放污染风险。更多还原

【Abstract】 Emissions of nitrogen and phosphorus(P) from coastal farmlands are one of water pollution sources of coastal wetlands and water body.The knowledge on phosphorus chemical behavior of the foreshore reclamation paddy soils can help evaluate water pollution risks of agricultural production and develop environmental friendly P management measures.The dynamics of phosphate adsorption at three temperatures(15℃,25℃,35℃) were investigated in the foreshore reclamation paddy soils originated at three historical periods(Song dynasty,Ming dynasty and Present age) in Cixi,Zhejiang,and thermodynamics parameter and of P adsorption in these soils were also estimated.The results showed that: 1) Kinetic curves of phosphate adsorption could be well described by Langmuir,Freundlich and Temkin equations with the best fitness of Freundlich equation,the sorption parameters of thermodynamics(△H0) were 4.39,11.40,15.97 kJ/mol,respectively;P sorption could be dominated by hydrogen bond forces and dipole bond forces referenced to the results of Von Open(1991).2) The Qm for these paddy soils tested followed the decrease order as bellow: Song dynasty>Ming dynasty>Present age,implying that capacity of soil phosphorus adsorption increased with the increase of rice-planting duration.The Qm was significantly positively correlated with soil organic matter(SOM)(p<0.01).Therefore,application of organic fertilizer induced to increase of SOM could be conducive to increase soil P adsorption capacity.Qm increased with increasing temperature suggested that phosphate fertilization could be used in summer to reduce the risk of P loss risk from soils.更多还原