Abstract

                                The Zn and B adsorption data clearly shows that the soils not only vary in their capacity to retain Zn and B but also in the energy with which they adsorb it. These two factors affect the ability of a soil to release Zn and B and to maintain supply in the soil solution. The rate of adsorption Zn and B study indicate that the equilibrium period of 24 h was sufficient to study the Zn and B adsorption characteristics of soils. The Elovichian model best described the kinetics of Zn and B adsorption by these soils. Though adsorption of Zn and B confirmed to both Langmuir and Freundlich adsorption isotherms, the fit was excellent with Langmuir adsorption isotherm for Zn and Freundlich adsorption isotherm for B. Clay, OM, CEC of the soils were significantly correlated with K values of Freundlich equation for B adsorption, b values of Langmuir equation for Zn adsorption. Removal of either OM or CaCO, reduced the adsorption capacity of B in the soils of Tamil Nadu. The study on the adsorption of Zn indicates that removal of OM, addition of P reduced the adsorption capacity as well as energy of its adsorption. P fertilization reduced the Zn requirement for optimum plant growth in soils of Tamil Nadu.

Key words : Zinc, Boron, Adsorption, Isotherm, Langmuir and Freundlich equations.