Influence of nutritional status of phosphorus on flowering in the olive (Olea europaea L.)

- Foliar application of P to young olive trees did not increase phosphorus concentration in leaves.
- Cultivars differs in tree vigor, phosphorus level and the time of first flowering.
- Application of P to well-nourished plants does not affect early flowering.

Two different field experiments were carried out during four years with one-year-old olive trees recently planted. In the first experiment, 'Hojiblanca', 'Picual' and 'Arbequina' received several foliar applications along each season of 0, 100 or 200 ppm phosphorus. The second experiment was established with 24 olive cultivars to determine the effect of cultivars in the nutritional status of phosphorus and flowering. No phosphorus fertilizers were applied in this experiment. Foliar application of phosphorus to young olive trees during several seasons did not increase phosphorus concentration in leaves. This lack of response to phosphorus application could be because these trees have high levels of phosphorus in leaves. Consequently, no effect on vegetative growth or flowering was observed in response to phosphorus application. Differences in vigor, phosphorus level, and the time of first flowering were observed among cultivars, but no relationship was found between leaf phosphorus concentration and vigor or the time of first flowering. Results indicate that if the nutritional status of phosphorus in olive trees is above the sufficiency threshold phosphorus does not affect flowering. The time of first flowering seems to depend on the cultivar.