Yield and Metal Composition of Lettuce and Wheat Grown on Soils Amended with Sewage Sludge Enriched with Cadmium, Copper, Nickel, and Zinc1
- G. A. Mitchell,
- F. T. Bingham and
- A. L. Page2
Lettuce (Lactuca sativa L. vat. longifolia) and wheat (Triticum aestivum L. ‘Inia’) were grown under greenhouse conditions on an acid and a calcareous soil amended with sewage sludge enriched with Cd, Cu, Ni, or Zn to determine relative toxicities of the metals and uptake characteristics of the test plants.
While the order of toxicities was not the same for all soil and plant-species combinations, Cd was, in general, most toxic followed by Ni, Cu, and Zn. The latter three metals were about equally toxic to wheat grown in the calcareous soil; in the acid soil, Cu was about four times and Ni about six times more toxic to wheat than was Zn. Yield results indicated strong soil and plant species effects. Nickel was more phytotoxic to lettuce and wheat grown in the acid than in the calcareous soil, whereas Cd, Cu, and Zn toxicity depended on plant species and metal-concentration range. At relatively low soil treatments, Cu and Cd were more toxic to lettuce grown in the calcareous than in the acid soil.
Both DTPA and water-soluble metal concentrations were significantly correlated with metal uptake by plants. Water-soluble concentrations of Cd, Cu, and Ni better predicted plant uptake of these metals while Zn uptake was more closely correlated with DTPA-soluble Zn.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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