2019 ASHS Annual Conference

A burgeoning olive industry is already present in Florida. The production area is estimated to be approximately 400 acres. However, little information about the establishment and nutrition of olives in this region is currently available. Moreover, studies on the seasonal changes of the nutrient content in olive trees growing under local environmental conditions have not yet been reported. The purpose of this research was to develop nutrient curves for nitrogen, phosphorus, and potassium in ‘Arbequina’ olives in Florida, based on analysis of foliar samples. Trees from three commercial farms in the counties of Gilchrist, Marion and Suwannee were established under irrigation between two to five years prior to collection of leaves from April 2018 to March 2019. Compared to Gilchrist and Marion counties, the trends of all nutrients were different in Suwannee county, the northernmost location. The trends for phosphorus and potassium were similar in Gilchrist and Marion counties. Although not always statistically significant, lower nutrient content was mostly observed in olives from Marion county. Nitrogen content decreased from April until August, and then increased to levels similar to April in Gilchrist and Marion counties. Trees from Marion county presented the lowest nitrogen values from June to August. The phosphorus content in trees from all locations varied along the course of this study, but it was lower during spring (April) compared to winter (December) for trees from Gilchrist and Suwannee counties. Phosphorus content was similar during spring and winter for trees from Marion county. An accumulation of potassium was observed from April to August in Gilchrist county, followed by an abrupt decrease in September. Trees from Marion county presented the lowest potassium content from June to January, but it increased in March. Trees in Gilchrist and Marion counties increased potassium content around October and maintained similar levels through March. When considering the macronutrients N, P, and K, the optimal time for collection of foliar samples may be between June and July, under the conditions of this research.