Zinc fertilization increases flowering and fruit yield of ‘Improved Meyer’ lemon

A field study was performed in southern Puerto Rico to determine the impact of zinc (Zn) fertilization in the productivity of 'Improved Meyer' lemon. The experiment was done in a Vertisol known to have relatively low concentrations of available Zn. Lemon trees that had reached the fruit production age were sprayed with Zn sulfate three times from spring to fall, for a total of 0 (control), 2, 4, 6, and 8 kg of Zn ha^-1. There were 7 trees of similar size per treatment. Flower relative abundance and fruit relative abundance were significantly affected by Zn rates, reaching the greatest values at the rate of 4 kg of Zn ha^-1, without further increase at higher Zn rates. Fruit weight and juice volume were also greater in lemons harvested from trees fertilized with 4 kg of Zn
ha^-1. These results show that under the conditions of this research, Zn fertilization enhanced flowering and fruit production in 'Improved Meyer' lemon, and the magnitude of the effect was rate dependent.