Olives have been cultivated in Europe for at least 7,000 years—for their oil and their fruit.¹ In fact, Spain, Greece, Turkey, and Italy produce the majority of the world’s olive crop² and the EU has a whole produces around 67% of the world’s olive oil.³

Yet, historically the olive tree has been a stingy, hostile, and uncooperative friend to man. The yield per tree was miserably low, with less than 2% of flowers becoming mature olives, and sometimes ending in total failure. Olive trees were difficult to propagate; young trees became old before their time, and then lived on, not quite sterile, for hundreds of years (some estimate up to 900 years⁴). A most unsatisfactory agricultural species.

As excellent alternative oils were developed, olive growing became less economically viable. Production declined, prices went up, consumption declined, and the industry became poorer and poorer. Some growers switched to other crops, yet large areas of the Mediterranean—more suited to olive-growing than other crops—seemed doomed to economic extinction. Then, a revolution began—la olivicultura moderna.

Olives and the EU

Thanks to a system of subsidies and price guarantees under the Common Agricultural Policy, the EU olive oil production has seen an 8% increase in recent years. Unfortunately, extreme weather events, including wildfires, droughts, and unseasonable temperatures have limited EU olive production over the past five years.⁵

Now, Italian lawmakers have proposed a national initiative to support individuals who may not farm as their primary occupation but nevertheless play a critical role in the conservation of olive groves. These growers include family land managers as well as agriturismos. Given that Italy has more than 1M hectares under olive cultivation, this could prove a significant development for all growers.

Adapting olive culture

On the olive culture side, perennial problems are at last being solved or circumvented. Out of 500 varietal types, 24 have been identified as having superior characteristics for:

• Propagation
• Yield
• Quality
• Resistance to fruit-drop

Newer methods of multiplication, particularly in vivo rooting under mist irrigation, have greatly improved the availability of healthy young trees, particularly in Spain. These trees now come into production in as little as three years, as opposed to an average wait of 15 years before. The new olives are single-stemmed, and therefore appropriate for mechanical harvesting.

Increases in productivity are being brought about by higher tree densities in the new Spanish plantations. Traditional densities were 80-100 trees per hectare; densities of 200 and more are now possible. At present, this tends to reduce the yield per tree, but the overall yield per hectare is up by about 40%.

Boron for plant nutrition

On the agrochemical side, startling advances are being made in pest control and plant nutrition. Historically, olives have received little or no remedial care, bar occasional pruning and removal of dead wood. Now, they often receive three or four treatments per year, and pests such as the olive fly and the olive moth are being eliminated.

In Spain, boron application has made a significant difference in crop yield. Olives typically are grown on calcareous soils which prevent or impede boron absorption. Given that olive trees are naturally low in boron and grown in extremely dry conditions, results in boron deficiency which leads to poor yields and sick trees.

For centuries, the trees themselves have been trying to tell their cultivators about boron deficiency through:

• Discolored leaves at the tips
• Prematurely shedding leaves
• Branches dying back
• Producing a multitude of barren suckers
• Deformed or corky fruit that fall to the ground unusable

Research leads to better outcomes

Boron’s essentiality to plant life has been accepted for more than 80 years, and the relatively high boron requirements for olive trees are well documented. There is now abundant proof that the age-old problems of fruit set, fertilization, die-back, sterile suckers, fruit drop, and deformed corky olives are significantly due to boron deficiency. 

Recent U.S. Borax research has shown that very small amounts of borate fertilizer, foliar application of 20-30 grams per tree, for example, can double or triple yields, even from old, notoriously infertile trees. Review our field studies to see how U.S. Borax products such as Granubor^® and Solubor^® can help your olive yield.

Contact our regional agriculture experts to learn more.

 

Resources

• Crop Guide: Olives
• Regional Solutions: Europe
• Granubor
• Solubor