Abstract
An irrigation study was conducted on young 'Valencia' orange (Citrus sinensis L. Osbeck) trees planted in January 1999 at the Indian River Research and Education Center in Ft. Pierce. Trees were irrigated with microsprinklers with top hats to direct the water into a 3 ft diameter area around the tree. Plots consisted of eight trees, with irrigation treatments during rain-free periods scheduled once per day (1D), every 3 days (3D), or whenever tensiometer readings at a depth of 15 cm exceeded 15 kPa (T15). One year after planting, the trees on the T15 treatment had similar trunk cross-sectional area, but slightly less height and canopy development than the other treatments. Two years after planting, the T15 treatment trees had about 90% of the height and canopy width of the other treatments and about 19% less trunk cross-sectional area. At 3 years after planting, trees on the 1D irrigation program had about 12% more trunk cross-sectional area, and about 10% more height than the other treatments. At 4 years after planting, the 1D treatment was superior in all respects to the other treatments. In March 2003, the 1D treatment trees had about 16-18% more trunk cross-sectional area, 5-8% more canopy width, and 7-10% more height than other treatments.
