The relative rates of release of potassium, calcium, and magnesium from soils during electrodialysis

The relative rates of release during electrodialysis of potassium, calcium and magnesium from field soils, from single‐base soils containing the three cations separately, and from a soil saturated with, equivalent amounts of all three cations, were studied. In all cases potassium was released much more rapidly than either calcium or magnesium. Potassium fertilization of the soil resulted in a quicker release not only of potassium but also of calcium and magnesium. The rates of release of calcium and magnesium were similar from single‐base soils, but the presence of potassium and calcium depressed the rate of release of magnesium. There was little difference in the relative rates of removal of the three bases during leaching of the triple‐base soil with ammonium acetate. The relatively easy release of potassium is possibly connected with the ‘luxury consumption’ of potassium by plants.