ASSESSMENT OF PLANT-AVAILABLE CADMIUM IN SOILS

A study has been made of the amounts of cadmium recovered by a variety of reagents and extraction procedures from soils to which Cd has been added. Correlation of these results with the Cd content of radish plants grown in these soils has shown that the most sensitive of several possible indices to Cd uptake by plants is the amount extracted by a 1-hr shaking with 1N ammonium nitrate solution at a soil/solution ratio of 1:10 (wt/vol). The greater efficiency of this extractant compared with other proposed extractants is ascribed to the system reflecting the natural pH of the soil which has a marked effect on cadmium availability to plants.