Comparison of cadmium uptake by five different food grain crops grown on three soils of varying pH

Abstract

Information is limited on the effect of food grain crop species on cadmium (Cd) uptake from soils varying widely in pH. In this study, 200 μg Cd kg‐1 as cadmium chloride (CdCl2) was added to three soils—Hartsells (pH 5.0), Greenville (pH 6.2), and Windthorst (pH 7.7). Five different food grain crops—flooded rice, soybean, cowpea, oat, and wheat—were grown to maturity. It was found that Cd uptake by the crops varied with soil pH and crop species. Cadmium concentrations in grain were significantly higher on the Hartsells soil than that on the Greenville and Windthorst soils, whereas no significant difference was found between the latter two soils. On the Hartsells soil, Cd concentration in grain followed the order of wheat=soybean > oat > flooded rice > cowpea. On the Greenville and Windthorst soils, the order followed wheat > soybean = flooded rice > oat = cowpea. Cadmium concentration in cowpea grain was the only one that did not exceed 0.100 mg Cd kg‐1, the maximum permissible concentration in cereal grains that is adopted by several European countries.