Distribution of available boron and sorption desorption behaviour of boron in some soils of Cooch Behar district of West Bengal: Part II - Sorption and desorption of boron.

摘要

Twenty four soil samples collected from different places of Cooch Behar district of West Bengal were used to estimate the adoption/desorption of applied boron. The sorption/desorption findings were fitted to the standard adsorption isotherms namely, Freundlich and Langmuri adsorption isotherms. The soils had the lower capacity of boron sorption. The Freundlich k value was higher during desorption run that in sorption run indicating greater affinity of sorbed boron for the soil surface, thereby leading to low desirability of once-sorbed boron. Similar trend was also found in the Langmuir adsorption maxima. The Freundlich equation gave a better fit than the Langmuir equation representing greater R2 values. Freundlich k had positive correlation with CEC clay and organic matter content of the soils. Similar trend was also observed in case of Langmuir adsorption isotherm indicating that the soils having higher clay and organic matter content have the greater adsorption sites for boron adsorption. The changes in Gibbs free energy for B adsorption on all the 24 soils were found to be positive indicating that B adsorption was not a spontaneous process and leachability of B was higher for these soils resulting in boron deficiency.