Effects of Foliar Applied Mg on Yield, Fruit Quality and Macronutrients of ‘Washington’ Navel Orange1

Where Mg deficient ‘Washington’ navel orange trees were sprayed with Mg, leaf Mg was increased from a deficient to an optimum level in the first year of application. However, it was not until the fourth year of application that a yield increase occurred. At least 2 sprays annually were required. There was an increase in total soluble solids in the juice as a result of the sprays, but there were no other consistent effects on fruit quality. Magnesium in the feeder roots was increased by the foliage sprays. Leaf K was decreased by the Mg sprays. One year after cessation of the sprays the leaf Mg was again in the deficiency range.