Cadmium-Enriched Sewage Sludge Application to Acid and Calcareous Soils: Effect on Soil and Nutrition of Lettuce, Corn, Tomato, and Swiss Chard
1982
Mahler, R. J. | Bingham, F. T. | Page, A. L. | Ryan, J. A.
Eight soils with pH values ranging from 4.8 to 7.8 were amended at a 1% rate with a municipal sewage sludge containing variable amounts of CdSO₄. The resultant concentrations of Cd in the soils ranged from 0.1 to 160 µg Cd/g. To observe the interactive effects of soil pH and Cd on elemental composition of plants, lettuce (Lactuca sativa var. Longifolia), tomato (Lycopersicon esculentum Mill.), sweet corn (Zea mays L.), and Swiss chard (Beta vulgaris var. cicla) were grown for 7 weeks in a greenhouse in pots containing the treated soils. Comparison of Cd availability to lettuce, Swiss chard, corn, and tomato grown on acid soils with that on calcareous soils revealed less Cd uptake by plants under alkaline soil conditions. The concentrations of Cd in the saturation extracts of the calcareous soil groups were significantly greater than those of the acid soil groups; however, this was not reflected in greater plant uptake of Cd from the calcareous soils. Cadmium additions to the soils generally decreased Zn and Mn concentrations in saturation extracts in calcareous soils. These decreases were reflected in reduced concentrations of Zn and Mn in leaves of the test crops. The relationships between saturation-extract compositions of Cd, Zn, and Mn and their plant compositions were found to be different for the acid as compared with the calcareous soil groups.
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