【目的】研究32年连续不同施肥对耕地棕壤K+吸附解吸动力学特征的影响。【方法】采用去离子水淋洗土壤,连续液流法研究9个不同施肥处理耕层土壤钾吸附解吸动力学特征。【结果】不同施肥处理土壤对K+吸附、解吸平衡时间变幅分别为26—65 min和65—130 min;平衡吸附量和平衡解吸量范围分别为7.40—19.44 cmol?kg-1和0.070—0.258 cmol?kg-1;反应速度与反应时间的关系符合方程V=A+Blnt,且线性关系良好;CEC、黏粒、有机质、速效钾与吸附解吸各参数呈现不同程度的相关性;4种方程中,Elovich和一级动力学方程分别是拟合吸附和解吸过程的最优模型。【结论】不同施肥处理K+吸附解吸动力学特征差异很大,施用有机肥可以提高土壤对钾素的吸附能力;施钾量越高的处理,解吸能力越强;长期定位不同施肥通过改变土壤理化性质影响棕壤钾素吸附解吸动力学特性;长期不同施肥钾素在土壤中吸附解吸动力学过程不同。
【Objective】The objective of study was to investigate the kinetics characteristics of K+ adsorption and desorption of brown soil under long-term (32 years) fertilization.【Method】Nine samples of different treatments were flowed through with deionized water as pretreatment. Miscible displacement techniques were used to study the adsorbing-desorbing process. 【Result】The equilibrium time of adsorption ranged from 26 min to 65 min, and that of desorption ranged 65-130 min. The ranges of equilibrium adsorbing capacity and the equilibrium desorbing capacity were 7.40-19.44 cmol?kg-1 and 0.070-0.258 cmol?kg-1. The relation between velocity of potassium adsorbing and time could be described with the model of V=A+Blnt. There were correlation between parameters of adsorption and desorption were related with CEC, Clay, OM and available K in different degrees. First-order, Elovich, Parabolic diffusion and Dual constant were used to describe the kinetics of K adsorption and desorption of experimental soils. The results showed that Elovich and First-order were the best kinetic models for describing adsorption and desorption, respectively.【Conclusion】There were great different characteristics of adsorption and desorption under different fertilizations. The ability of adsorption could be increased by applying organic manure. And the ability of desorption improved with potassium rates. The effect of long-term fertilization on K+ adsorption and desorption kinetics of brown soil was up to the changes of physic-chemical properties of soil. There were different dynamic processes of potassium in soil under different fertilizations.