Arsenic Residue Toxicity to Vegetable Crops Grown on Plainfield Sand1
- L. W. Jacobs,
- D. R. Keeney and
- L. M. Walsh2
In a field study, sodium arsenite, which is used widely in Wisconsin as a defoliant for potatoes, was applied to a Plainfield sand at rates ranging from 45 to 720 kg As/ha. The plots were planted to potatoes in 1967; peas, snap beans, and sweet corn in 1968; and to peas in 1969. Yields of potatoes were greater than check at the 45 and 90 kg As/ha rates, but decreased to 79 and 24% of check yield at the high As rates. Snap bean and sweet corn yields also decreased with increasing As, and no growth was obtained on the high As plots. The As content of above-ground portions of potatoes varied widely, and bore no relationship to As treatment. Evidence of As contamination by windblown As-treated soil was obtained. Arsenic was below detectable limits in edible portions of peas and sweet corn, but up to 0.5 ppm of As accumulated in potato tubers and up to 84 ppm in potato peelings. Detectable levels of As occurred in snap beans, with up to 1 ppm As accumulating in snap bean seeds and pods from the 180 kg As/ha plots. Yield decreases were related highly to total, 1 N NH4OAc extractable and Bray P-l extracfcible As. The data suggest that, with the Plainfield sand, marked yield reductions of peas, snap beans, andsweet corn occur at about 10, 1, and 5 ppm of total,N NH4OAc, or Bray P-l extractable As, respectively. The finding that yield reductions and As contamination of vegetable crops will occur indicates that use of As as a potato vine defoliant on sandy soils should be discouraged.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .