The cation exchange capacity of plant roots, and its relationship to the uptake of insoluble nutrients

Abstract

The cation exchange capacity (C.E.C.) of the roots of 20 plant species was measured by a rapid technique not involving toxic reagents or harmful temperatures. Significant differences between the root C.E.C. of various species were found, and with three exceptions, legumes > herbs > grasses. Nitrogen supply had little effect on the legumes and herbs, but significantly increased the C.E.C. of two grasses. The concentrations of calcium and phosphorus in the tops of plants utilizing rock phosphate were each positively correlated with root C.E.C. The concentration of phosphorus was not greater in the tops of plants with relatively large root systems.