BEHAVIOR OF CADMIUM IN CONTRASTING INDIAN SOILS

Adsorption behaviour, chemical speciation and plant uptake of cadmium (Cd) was studied in two contrasting soil types of India, namely, an Ul tisol and a Vertisol. Results indicated that both soil types followed Freundlich adsorption isotherm; the adsorption capacity (mu g Cd g(-1) soil) of Vertisol was about thirty times more than that of Ultisol. D ata on chemical speciation studies have shown that the extraction of p lant-available forms of Cd (exchangeable + adsorbed + organic-bound fr actions) was considerably higher from Ultisol than from Vertisol. The results of adsorption behaviour and chemical speciation studies were w ell reflected in the plant-uptake studies, where, a significant reduct ion in forage yield was observed at 100 ppm Cd in Ultisol and 200 ppm Cd in Vertisol due to significantly higher plant tissue concentrations of Cd grown in the Ultisol than that grown in the Vertisol.