用动力学方法研究土壤矿物层间钾的释放

STUDY OF THE INTERLAYER POTASSIUM RELEASE OF SOIL MINERALS THROUGH KINETIC METHODS

本文就业已用于研究土壤矿物层间钾释放的动力学方法进行了归类和评述,并对钾的释放速率及其影响因素,以及钾的释放动力学机理作了相对详细的综述。研究者们的结果表明,粒径小的土壤颗粒钾的释放速度比大者快;三八面体硅酸盐矿物比二八面体的释放速度大。云母族矿物钾释放速度序为:铁质黑云母(三八面体)>镁质金云母(三八百体)>白云母(二八面体),它们的释放量与时间的平方根成线性关系。Martin的试验结果表明,供试土壤层间钾的释放速度可用一阶扩散方程很好地描述。氢离子浓度过高时(pH<3),会导致粘粒结构的破坏,从而加快了钾的释放速度。温度(T)、淋洗速度(L)和盐浓度(N)与钾的释放速度(r)的关系可表达为r=k(L△TN^(1/2))。钾的释放过程中涉及了多种动力学机理,其中层间扩散是钾释放中非常基本的机理。

In this paper, the kinetic methods used in studying the release of inter-layer K of soil minerals are grouped and commented on, and the rate of K-release and the affecting factors as well as the kinetic mechanisms are reviewed in more detail. The researchers' results indicated that, small clays released interlayer K at a higher rate than larger ones, and so did the triotahedral ( trio. )silicate minerals than the dioctahedral ( dio. ) ones.The rates of K-release of micas in releasing order were. Fe-rich biotite ( trio. )>Mg-rich phlogopite ( trio. ) >muscuvite ( dio. ) .Their fraction of interlayer K released was a linear function of the square root of time.Martin's experimental data suggested that the rate of K-release of soils employed could be discribed satisfactarily by the first-order diffusion equation. Hydrogen ion concentration up to 10^(-8) or higher ( pH<3 ) may lead to the distruction of the clay structure so as to speed up the rate of K-release. The relation between temperature ( T ) ,the rate of leaching ( L ) and the salt concentration ( N ) and the rate of K-release could be expressed as r = k(L. AT-N1/2 ) . During the release of potassium, several kinetic mechanisms were involved simultaneously, however, the interdiffusioa -was the most essential one.