石灰改良对酸性土壤磷解吸动力学特征的影响

采用连续液流法研究了石灰施用对酸性土壤磷解吸动力学特征的影响.结果表明,石灰处理并不影响动力学模型对磷酸根的解吸机制,选用的抛物线方程、Elovieh方程、权函数方程等6个动力学模型对磷酸根解吸过程的拟合效果均达到显著水平,其中,以权函数方程和抛物线方程拟合度最佳.与对照相比.石灰改良后,赤红壤和黄红壤对磷的解吸具有较高的初始瞬时速率,黄红壤具有较低的初始瞬时速率.扩散机制是磷从固相表面向溶液的移动机制.抛物线扩散方程的扩散系数R可望成为较好的指示土壤磷素生物有效性的良好指标.

Study on the Characteristics of Phosphorus Adsorption-desorption in Acid Soils under Lime Amendment

By the technique of sequent liquid flow method, the influence of lime amendment to phosphorus adsorptiondesorption kinetics were studied in three acid soils. Zero-order,first-order, parabolic diffusion, Elovich function, power, exponent function equation were selected to fit the experimental dada and all the equations were up to extremely significant level. Among these equation, power function aud parabolic diffusion equation had the best fitted effect. Lime application treatment had no effect on kinetic models fitted to P desorption. P diffusion and movement was the mechanism of P from solution to solid surface. Compared with the contrast treatment, P in lime application treatment had higher rate in the beginning stage in lateritlc red soil and yellow red soil, while lower rate in brown red soil. Diffusion coefficient R in parabolic diffusion equation could possibly become a good index to reflect soil P bioavailability.