Metal Accumulation in Corn and Barley Grown on a Sludge-amended Typic Ochraqualf
1987
Rappaport, B. D. | Martens, D. C. | Reneau, R. B. | Simpson, T. W.
A field experiment was conducted during the 1984 and 1985 growing seasons in the Atlantic Coastal Plain region to evaluate heavy metal accumulation in corn (Zea mays L.) grain and stover and in barley silage (Hordeum vulgate L.) grown on a poorly drained, sludge-amended soil. The study was conducted using in situ controlled lateral flow plots (1.5 by 2.3 m) on Acredale silt loam (fine-silty, mixed, thermic, Typic Ochraqualfs) with a cation exchange capacity of 6.9 molc kg⁻¹ and a pH of 6.6. An aerobically digested sludge from a wastewater treatment plant with major industrial inputs was applied to the plots in 1984 at rates of 0, 42, and 84 dry Mg ha⁻¹. At the highest application rate, 1.8, 304, 17.2, and 248 kg ha⁻¹ of Cd, Cu, Ni, and Zn were applied, respectively. Cadmium concentration was <0.01 mg kg⁻¹ in the corn grain in both 1984 and 1985. Sludge application increased the concentration of Ni and Zn in the corn grain in 1984 and 1985. Levels of Cd and Cu were unaffected by sludge application in the corn grain for both years. Copper, Ni, and Zn levels were increased in the barley silage by sludge application. Levels of DTPA (diethylenetriaminepentaacetic acid)-extractable metal in the Ap horizon were increased by sludge applicatioo and were 0.25, 60, 2, and 30 mg Cd, Cu, Ni, and Zn kg⁻¹ in the highest sludge treatment, respectively. The DTPA-extractable Cd, Cu, Ni, and Zn within the soil profile indicated no downward metal movement. On this poorly drained soil, phytotoxicity due to metals did not occur even where Cu was applied in excess of 280 kg ha⁻¹, which is the maximum amount of Cu that could be applied to the soil based on USEPA guidelines.
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