Vol. 109 (1996): Proceedings of the Florida State Horticultural Society
Citrus

DOES MOVING UNDERTREE SPRINKLERS INTO THE CANOPY ADD PROTECTION FROM COLD DAMAGE?

Published 1996-12-01

Keywords

  • cold protection,
  • frost protection,
  • irrigation,
  • sprinkling,
  • microsprinklers,
  • microclimate modification
  • ...More
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Abstract

Little difference in the level of protection offered by various microsprinkler placements was observed following the Feb. 5, 1996 freeze in a 5 acre grove on the Main Campus of the University of Florida, Gainesville, during which the temperature in the grove dropped to 20.5F within the irrigated grove and to 15F at the Agronomy Farm 8 miles WNW of the grove. Damage to the trees was ranked from 1 (extensively damaged) through 9 (least damaged) on Mar. 14, 1996. The 455 trees were protected by 11 methods of sprinkler placement but with the rate to each tree held constant. The methods varied in both sprinkler number and in their locations on the ground beneath the tree and locations within the canopy. The means and SD for these treatments were 6.48 ± 1.55, 6.45 ± 1.69, 6.39 ± 1.55, 6.37 ± 1.69, 6.29 ± 1.62, 6.29 ±± 1.79, 6.10 ± 1.91, 6.07 ± 1.62, 5.76 ± 1.41, 5.71 ± 1.66. No significant difference in the protection provided between any of the treatments was shown. No significant differences were observed between the undertree and intree treatments; 166 trees with sprinklers under them were 5.99 ± 1.56 whereas the 289 trees with sprinklers within the canopy were 6.28 ± 1.65. Buoyancy of water vapor relative to dry air may explain these results.