Cadmium sulfate application to sludge‐amended soils: III. Relationship between treatment and plant available cadmium, zinc, and manganese1

Abstract

Swiss chard (Beta vulgaris var. cicla) and corn (Zea mays L.) were used as biological indicators of Cd, Zn and Mn availability in 12 soils amended with and without sludge, CdSO4 and CaCO3. Soil Cd, Zn and Mn were partitioned into six fractions: soluble, exchangeable, adsorbed, organically bound, carbonate bound and sulfide bound, by theuse of H2O, KNO3, H2O, NaOH, EDTA and HNO3, respectively. The data indicate that the major portion of total Cd was found in the carbonate, residual and organic fractions. Addition of CaCO3 caused an increase in the soluble and exchangeable fractions of Cd in the soils. The concentrations of Cd in the saturation extracts of the limed soils were significantly greater than those of the unlimed soils; however, this was not reflected in greater plant uptake of Cd from limed soils.