Cadmium Adsorption by Soils and Uptake by Plants as Affected by Soil Chemical Properties
1981
McBride, M. B. | Tyler, L. D. | Hovde, D. A.
The quantity of Cd²⁺ adsorbed by soils from the northeastern USA was measured at a given equilibrium concentration (10⁻⁵M) of the metal in soil solution. This “retention capacity” was strongly related by a linear function to the exchangeable Ca²⁺ content of the soils. In addition, Cd²⁺ uptake by corn plants grown in these soils amended with 1-µg Cd²⁺/g of soil was measured and found to be related to the retention capacity of the soil for Cd²⁺ by a curvilinear function. Although organic matter and clay in soil were able to limit Cd²⁺ uptake by the plants, the best soil indicators of Cd²⁺ availability were the retention capacity and exchangeable base (mainly Ca²⁺) content. The ability of exchangeable bases to account for most of the variability in Cd²⁺ adsorption by the soils as well as uptake by the plants is attributed to the important role of Cd²⁺-Ca²⁺ exchange reactions in the soil.
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