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Greenhouse and laboratory experiments were conducted to characterize the chemical form or forms of Cd, which is a contaminant in phosphate fertilizers, in terms of plant availability and extractability from soil. Winter wheat (Triticum aestivum L.), cv. Nugaines, was grown on Mountview silt

This study related Cd-Zn concentrations in plants to levels of Cd and Zn in soil recovered by several extractants soon after application of Cd and Zn sources to soil. Cadmium nitrate and ZnSO/sub 4/ or Zn(C/sub 2/H/sub 3/O/sub 2/)/sub 2/ were mixed with a Zn-deficient Crowley silt loam soil, cropped with corn (Zea mays L.), and then cropped with Swiss chard (Beta vulgaris). Applied Cd significantly increased the Cd/Zn ratio in both crops, especially in Swiss chard, which accumulates heavy metals. A previously published sequential-extraction procedure was used to fractionate Cd and Zn in soil after the corn harvest. Results of statistical analyses showed the highest correlation between Cd uptake by each crop and the carbonate and sulfide fractions of Cd in soil. Including other Cd fractions resulted in only slightly higher R/sup 2/ values. Zinc uptake by each crop was best related to the organic fraction of Zn in soil, and including the other Zn fractions did not affect the relationship. These results show that Cd and Zn uptake by corn or Swiss chard was not related to similar chemical fractions of these elements in soil, and that the Cd/Zn ratio in plant tops was significantly affected by bothmore » Cd and Zn applications to soil.« less