N and K fertilization usually increases olive fruit oil content as well as fruit size and pulp to pit ratio. The
objective of this work was to investigate whether the increase in fruit oil content occurs via increased oil
concentration in the pulp, or via increased fraction of pulp in the fruit. In 2009 Leccino olive trees were
fertilized with the equivalent of 180 kg of urea-N, split in three equal doses (April, June, September). In
April, K2O fertilizer (potassium sulphate) was also applied for an equivalent amount of 100 kg of K2O per
hectare. Control trees were not fertilized. Fresh and dry weight offruit, pulp and pit, fruit and pulp oil and
water content, pulp firmness and fruit maturity index were measured throughout fruit growth, on fruit
samples from both fertilized and control trees. At all sampling dates, fertilized plants had significantly
greater fruit weight, both on a fresh (+23% on average) and dry (+17% on average) basis. Pulp/pit ratio also
increased significantly with fertilization (+23%, both on fresh and dry basis). Fruits offertilized plants also
had significantly higher oil content on dry matter basis (+9% on average). However, pulp oil content did
not differ significantly between treated and control plants. The same was found for water content, which
was significantly higher in the fruit of fertilized plants (+5% on average), but not in the pulp. Fertilization
did not affect fruit maturation (i.e., color and pulp firmness).