Effect of Municipal Wastes on Crop Yields and Uptake of Heavy Metals1
- P. M. Giordano,
- J. J. Mortvedt and
- D. A. Mays2
A field experiment was initiated in fall 1971 to compare 90-, 180-, and 360-kg/ha rates of Zn supplied in ZnSO4 and in garbage compost or sewage sludge. The same treatments were reapplied to half of each plot in fall 1972. Forage yields of sweet corn (Zea mays L.) in 1972 and 1973 were higher with applied compost and sludge but were unaffected or reduced by ZnSO4 applications. Concentrations of Zn were much higher in forage with ZnSO4 than with the organic wastes; concentrations in grain were similar among all treatments. Reapplication of the treatments did not result in proportional increases in heavy metal concentrations in either forage or grain. However, concentrations of Cd in forage and grain were about threefold higher with compost and sludge.
Bush beans (Phaseolus vulgaris), double-cropped after sweet corn each year, were more sensitive to excessive Zn. All rates of ZnSO4 and sewage sludge depressed yields of mature pods, and dry matter yields of bean vines were lower with the high rate of ZnSO4 but relatively unaffected by sludge. Concentrations of Cd and Ni were slightly higher in vines and pods from sludge-treated plots.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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