Effect of misting on air temperature and humidity and its relationship with fruit set and yield of navel orange

Abstract

The effect of misting (fine-drop microsprinkling over the canopy) on air temperature and humidity under the canopy of the trees, and its relationship to fruit set and fruit yield in orange (Citrus sinensis L.) was studied. The study was conducted in a Washington var. Navel orange, orchard in Güemez, Tamaulipas, México, during the 2001 production cycle. Misting was done with microsprinklers placed over the tree crowns at a rate of 2.0 mm h ^-1, with one-hour cycles, from March to June, 2001. The treatments evaluated were: T1=30°C, T2=34°C, T3=38°C, which were the air temperatures to begin misting, plus T4, the control treatment without misting. When the air temperature was above or equal to 36°C and solar radiation was above or equal to 900 Wm ^-2, misting reduced air temperature up to 5°C inside the canopy and increased air water vapor pressure up to 12% between 12:30 and 16:00 h when there was a greater incidence of solar radiation. Misting at T 30°C increased fruit set and fruit yield. A correlation of -0.99 between the reduction in air temperature induced by misting and fruit yield was observed. Misting had no effect on internal and external fruit quality.