Growing Olive
Crop Nutrition Advice

Olive (Olea europaea L. or ‘European olive’) belongs to the Oleaceae family. Known to have originated from the Eastern Mediterranean region of the Middle East, it grows nowadays in almost all Mediterranean countries and in the US, China, Argentina, Australia, Mexico, and other countries. Orchards comprised of dozens of different varieties are planted on over 11 million ha, producing approximately 21 million tons of olives from which approximately 2.5 – 3.2 million tons of olive oil are extracted, a decline of 1 million mt of oil compared to a few years back. Spain, Italy, and Greece are the primary producers. The reduction in olive production is largely attributed to arid weather in Spain and a bacterial disease, Xylella fastidiosa, found in olive trees in Italy.

In the last few decades, in response to strong global demand, olive cultivation has shifted from traditional extensive, widely spaced, and rain-fed orchards to intensive, closely spaced, and irrigated orchards using fertigation, leading to an increase in yield and oil production. These increases in olive production have been achieved with only a minor increase in the cultivated area and so can be mostly attributed to management intensification.

Olive trees are long-lived plants that produce stable yields for many decades. Most ‘monumental’ olive trees have a maximum age between 300 and 500 years. More than any other fruit tree, olives have historically had a special, even sacred, symbolic meaning and have been central to the development of culture and food. The most ancient oil press facility (for olive oil extraction) was found at an archeological site near Haifa, Israel, and dates to ~5,000 years BC. In ancient Greece, olive oil was considered to be ‘liquid gold’. To Hippocrates, it was ‘the great healer’ and is still referred to as the ‘tree of peace’.

The olive tree is native and well adapted to the Mediterranean basin, where it is most often grown in nutrient-poor, shallow, and rocky hillside soils and where summer drought prevails. As a result, it was assumed that olive trees have a low nutrient demand. However, such assumptions are not supported by evidence but rather based on observations made in orchards under rainfed conditions. Moreover, the nutrient requirements of modern, high-density orchards that are well irrigated and fertigated are significant. Olive trees respond well to fertilization, even in shallow hillside soils, where trees respond with an increase in the number of perfect flowers, fruit set, and overall productivity.

Olive is salt tolerant, depending on the variety. Olive yield will only be reduced at high levels of EC, e.g., a yield decrease of 10% can occur at EC_e 4.0-6.0 dS/m. Yet olives can grow at a higher threshold, up to 6-8 dS/m, with high calcium status in soil. Saline irrigation water may increase desirable polyphenol and tocopherol levels in olive oil but can also undesirably alter the fatty acids composition.    

What are the most Common Uses of Olives?

Most of the olive harvest (around 80%) is used for oil extraction. ‘Table olives’ are a slowly growing market (~1.5% pa) of approximately 3 million mt. Olives are also used in the cosmetics industry.

The percentage of olive oil in ripe olive fruit is between 15-30%. The composition of olive oil is primarily triacylglycerols (~99%), including 55-83% oleic acid, 7.5-20% palmitic acid, and 3.5-21% linoleic acid. Olive oil is broadly classified into several grades, the most widely known of which are extra-virgin and virgin olive oil (EVOO and VOO, respectively). Free fatty acid (FFA) content is a primary parameter for olive oil quality, determining its market value and suitability for human consumption. Olive oil is classified as EVOO when its FFA content is less than 0.8%, whereas non-edible olive oil contains more than 3.3% FFA. Phenolic compounds (polyphenolics, PP) are antioxidants widely recognized for their contribution to the health of consumers and the quality of olive oil. Hence, the PP content of EVOO or VOO is another important quality parameter. The European Food Safety Authority (EFSA) regulation EU432/2012 states that olive oil phenols contribute to the protection of blood lipids from oxidative stress when their level is above 250 mg/kg. PP also affects the sensory properties of olive oil, determining its bitterness and pungency. ‘Lampante oil’ has poor quality and strong, unpleasant taste, high acidity, and impurities, making it inedible olive oil for humans. Lampante oil must be refined to improve impurities, reduce acidity, and improve its overall quality to make it suitable for consumption.

What are the most Important Nutrients for Olives?

 Nitrogen

Nitrogen (N) positively affects shoot and bud growth, percentage of perfect flowers, fruit set, and overall productivity. However, over-application of N may decrease oil quality and reduce fruit set and fruit number per tree. N supply is needed in spring for the vegetative growth and growth of the shoots that will bear flowers in the following season.

Phosphorus

Phosphorus (P) affects the rate of reproductive bud break, inflorescence weight, number of perfect (hermaphrodite) flowers, pistil weight, fruitlet persistence, fruit set, and, therefore, the total number of fruits (Erel et al., 2016).

Averages ± standard deviation of: phosphorus (P) concentration in irrigation solution, and corresponding P leaf concentration (%) measured during the flowering periods, reproductive bud break (%), and total number of fruit per tree for each of the two years of study. Different letters indicate values with significant differences at p<0.05 (6 repetitions).

Potassium

Olive is highly efficient at potassium (K) utilization, hence potassium nutrition has a relatively low impact on its growth and productivity. However, K levels in leaves are affected by K fertilization. If leaf K drops to extremely low values (below 0.26%), productivity will be impaired. Moderate K deficiency may impair the ability of plants to regulate stomatal closure. Potassium can be effectively replaced by sodium (Na) while maintaining similar CO₂ assimilation rates. Research shows that this is probably because of physiological adaptation to shallow, rocky infertile soils common in olive’s natural habitat.

Olive Nutrient Requirements and Fertilization

An irrigated orchard of table olives should be given N at a rate of approximately 200 kg/ha, or a lower level (approximately 150 kg/ha) when the crop is used for oil extraction.

In orchards with P deficiency (by lab analysis), the recommendation is to provide between 50-100 kg/ha P₂O₅, given in the spring. It is recommended to fertilize with K at a rate of approximately 200-300 kg/ha K₂O.

Foliar spray with potassium is a common practice for olives trees. In Spain and other Mediterranean countries, foliar applications of potassium chloride (KCl) are used. Agroleaf Power® with a high N:K ratio should be used in spring and a high K:N at later stages, at fruit maturation.

When zinc (Zn) in leaves is below 15 ppm, a foliar application is recommended twice during spring. In the case of boron (B) deficiency (<20 ppm in leaves), use Nutrivant Starter Olive 3%, or other B source, as a foliar spray in February (northern hemisphere). Source: Olive Board, Israel (הנחיות למגדלי זיתים- ענף הזית מועצת הצמחים (oliveboard.org.il)

When planting young olive seedlings, it is recommended to add fertilizers in the planting hole. This will deliver a nutrient supply for a few months without the risk of creating high salinity around the young root system. ICL’s Agroblen® is ideal for this purpose.

Organic olive production is practiced on approximately 1 million ha, accounting for 15% of permanent organic cropland and 8% of global area. Olives and coffee are the main crops with such a large share of production under organic management. ICL’s Polysulphate® and ICL’s potash are an approved inputs for organic farming under EU 2018/848.

Olive Deficiency and Toxicity Symptoms

Potassium deficiency in olive leaves, Jaen region, Spain. Photo by Dr. Francisco Morell, ICL Agronomist, Spain.

Product Type

Literature & Guides

1. Decision-support system for Olive Orchard Management. Dag et al. Center for Fertilization and Plant Nutrition (CFPN)
2. Effect of macronutrient fertilization on olive oil composition and quality under irrigated, intensive cultivation management. Zipori et al., 2022. doi: 10.1002/jsfa.12110
3. Effects of reclaimed wastewater irrigation and fertigation level on olive oil composition and quality. Basheer et al., 2019. J Sci Food Agric 99: 6342–6349. doi: 10.1002/jsfa.9911
4. Elevated fruit nitrogen impairs oil biosynthesis in olive (Olea europaea). Erel et al., 2023. Front. Plant Sci. 14:1180391. doi: 10.3389/fpls.2023.1180391
5. FAO Land & Water: Olive, Food and Agriculture Organization of the United Nations (fao.org)
6. Innovations towards sustainable olive crop management: a new dawn by precision agriculture including endo-therapy. Grandi et al., 2023. Plant Sci., 06 June 2023 Sec. Crop and Product Physiology Volume 14 – 2023. doi: 10.3389/fpls.2023.1180632
7. Olive Oil Varietals and Flavors – International Olive Council (internationaloliveoil.org)
8. Phosphorous Nutritional Level, Carbohydrate Reserves and Flower Quality in Olives. Erel et al., 2016. PLOS ONE 11(12): e0167591. doi: 10.1371/journal.pone.0167591
9. Olive Board, Israel: הנחיות למגדלי זיתים- ענף הזית מועצת הצמחים (oliveboard.org.il)
10. Potassium starvation increases stomatal conductance in olive trees. Arquero et al., 2006. HortScience 41(2):433-436. doi: 10.21273/HORTSCI.41.2.433
11. Sodium replacement of potassium in physiological processes of olive trees (var. Barnea) as affected by drought. Erel et al., 2014. Tree Physiology 34, 1102–1117. doi:1093/treephys/tpu081
12. Soil remediating measures for improving growth and production in an olive orchard grown in highly sodic soils. Poster presented at the IX International Symposium on Mineral Nutrition of Fruit Crops 2021. Center for Fertilization and Plant Nutrition (CFPN).
13. Sustainable Management of Olive Orchard Nutrition: A Review. Zipori et al., 2020. doi: 10.3390/agriculture10010011
14. The importance of olive (Olea europaea L.) tree nutritional status on its productivity. Erel et al., 2019. Scientia Horticulturae 159 (2013) 8–18. doi: 10.1016/j.scienta.2013.04.036
15. Understanding olive adaptation to abiotic stresses as a tool to increase crop performance. Fernández, 2014. Environmental and Experimental Botany, 103. doi: 10.1016/j.envexpbot.2013.12.003
16. The World of Organic Agriculture Statistics and Emerging Trends 2023. Willer et al. FiBL-IFOAM.

Field Experiments and Agronomic Reports

1. Effects of Potassium Foliar Spray on Olive, Peach and Plum, Part 1: Olive Experiments. Mimoun et al., 2008 (ipipotash.org)
2. Effects of Potassium Foliar Spray on Olive, Peach and Plum. Part 2: Peach and Plum Experiments. Mimoun et al., 2009 (ipipotash.org )
3. Responses of Olive (cv. Chemlali) and Pistachio (cv. Mateur) after Five Years of Experiment to Potassium Mineral Nutrition under Rain Fed Condition. Elloumi et al., 2010. (ipipotash.org)
4. Soil Amendments Effects