Biostimulants and nitrogen affect pomegranate flowering and fruiting

Research was conducted in Puerto Rico to assess the effects of nitrogen rates and soil-applied biostimulants on the flower and fruit production of ‘Ambrosia’ pomegranate. The plants were grown from cuttings, in plastic containers 40 cm in height and 40 cm in diameter filled with a vertisol soil from Lajas, Puerto Rico. The treatments were two nitrogen rates (100 and 125 g N tree^-1 year^-1) combined with three biostimulant treatments (no biostimulant, an amino acid formulation for soil application, and an extract of the marine alga Ascophyllum nodosum). Biostimulant application was done every 2 weeks as a soil drench. The combination of 100 g of nitrogen and no biostimulant was considered the control treatment. Among the treatments, significantly more flowers were produced by trees receiving the combination of amino acids and 100 g of N, leading to increased fruit production. When pomegranate trees were treated with amino acids and the nitrogen rate was elevated to 125 g tree^-1, flower production was similar to that of control trees. Alga extract treatments did not increase flower production, but increased fruit retention. This research showed that some biostimulants such as amino acid and alga extract formulations may be used to manage flowering and fruit yield in pomegranate in a tropical environment.