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Effects of accumulated fluoride on yields and fruit quality of Washington navel oranges

Journal Article · · Proc. Am. Soc. Hortic. Sci.; (United States)
OSTI ID:6308497

Bearing Washington navel orange trees were sprayed periodically over a 6 year period with dilute NaF and NaCl solutions. Approximately 15 sprayings with .0025 or .00125N NaF solutions were applied between March 15 and September 15 to produce F accumulations of 150 and 75 ppm F in bloom cycle foliage. Control trees were sprayed with .0025N NaCl to eliminate Na as a factor in the experiment. Fluoride toxicity symptoms produced by these treatments were indistinguishable from those produced by exposure of citrus trees to HF gas and consisted of (1) a characteristic interveinal chlorosis pattern, (2) premature leaf drop, and (3) reduced leaf size. In addition, there were significant reductions in fruit production beginning with the third year of treatment. For the 6 year period, yields were reduced 15% by the annual accumulation of 75 ppm F and 22% by the accumulation of 150 ppm F (dry weight basis) in bloom cycle foliage. No effects of the F treatments on fruit quality criteria (taste, vitamin C, citric acid, soluble solids, size, juice content, rind thickness) were observed in these experiments. Very little of the F applied as sprays found its way into the fruit.

Research Organization:
Univ. of California, Riverside
OSTI ID:
6308497
Journal Information:
Proc. Am. Soc. Hortic. Sci.; (United States), Journal Name: Proc. Am. Soc. Hortic. Sci.; (United States) Vol. 91; ISSN PASHA
Country of Publication:
United States
Language:
English