Croatian Olive Grower Innovates to Overcome Drought, Pests

From irrigating at night to covering developed fruit in kaolin clay, one Croatian producer is adapting to the country’s increasingly hot and dry summers.
Josip Pavlica
By Nedjeljko Jusup
Aug. 26, 2022 16:28 UTC

In recent years, extreme sum­mer droughts have become a sig­nif­i­cant chal­lenge for Croatian olive grow­ers.

The dry peri­ods are get­ting longer and more extreme as spring pre­cip­i­ta­tion becomes increas­ingly scarce and water reserves in the soil are not renewed.

These mea­sures are very use­ful, but water is sim­ply an irre­place­able ele­ment that enables high-qual­ity, reg­u­lar and con­tin­u­ous pro­duc­tion.- Josip Pavlica, olive grower and agron­o­mist

However, Josip Pavlica, a 28-year-old agron­o­mist and olive grower from Zadar, Dalmatia, has devel­oped some strate­gies to help farm­ers make the most of the rain that does fall ahead of the har­vest.

In order to encour­age bet­ter water accu­mu­la­tion in the soil, I first did an autumn tillage,” said Pavlica, who is also the sec­re­tary of the Association of Olive Growers of Zadar County. Then I add min­eral fer­til­izer with an empha­sis on phos­pho­rus and potas­sium to the soil, as well as indis­pens­able organic fer­til­izer.”

See Also:A Croatian Agronomist’s Guide to Olive Tree Pruning

This ensures a suf­fi­cient amount of nutri­ents and reduces the pop­u­la­tion of weeds, which com­pete with olive trees for water and nutri­ents.

Furthermore, at the begin­ning of spring, in his olive grove in the north­ern Dalmatian region of Zemunik Gornji, Josip imple­ments top-feed­ing with an empha­sis on nitro­gen. He also per­forms shal­low tillage to pre­serve the exist­ing mois­ture in the soil.

Also, in the spring and sum­mer, he car­ries out foliar feed­ing sev­eral times with a com­bi­na­tion of fer­til­iz­ers con­tain­ing macro and microele­ments. Finally, he adds a bios­tim­u­lant to pre­pare the plant for the stress caused by arid con­di­tions.

Starting in the cur­rent grow­ing sea­son, he also started treat­ing his olives with a prepa­ra­tion based on kaolin clay pre­serves mois­ture in the trees’ leaves and deters olive fruit fly infes­ta­tions.


Spraying the olives

The white color causes the sun’s rays to be reflected, which warms the tree to a lesser extent and reduces evap­o­tran­spi­ra­tion and thus water loss,” Pavlica said.

He adds that kaolin clay has proven to be very good in prac­tice against the olive fruit fly, the most per­ni­cious olive pest.

When it cov­ers the fruit, the clay cre­ates a bar­rier the fly can­not pen­e­trate. The white color also makes the fruit unrec­og­niz­able to the fly.


Kaolin clay protects against pests

This kind of treat­ment is com­pletely eco­log­i­cal and does not leave any residues in the oil,” Pavlica said.

However, he added that all these mea­sures are unnec­es­sary if the olive trees are not get­ting enough water to pro­duce fruit in the first place.

All these pre­vi­ously men­tioned mea­sures are very use­ful, but water is sim­ply an irre­place­able ele­ment that enables high-qual­ity, reg­u­lar and con­tin­u­ous pro­duc­tion,” Pavlica said.

Therefore, he is con­sid­er­ing whether to look for an under­ground water source to pre­serve the qual­ity and quan­tity of the crop. This is usu­ally a rather expen­sive under­tak­ing, but it is increas­ingly likely that it will become inevitable.

Encouraged by the exam­ple of the award-win­ning pro­ducer, Ivica Vlatković, Pavlic intends to plant new olive vari­eties that come from sub-Saharan Africa, which tol­er­ate high tem­per­a­tures much bet­ter than the native Oblica vari­ety.

Furthermore, the irri­ga­tion of olive groves requires large amounts of water, with each tree requir­ing sev­eral hun­dred liters of water per round of irri­ga­tion.

Some olive grow­ers, includ­ing Vlatković, have already begun to tackle this prob­lem by irri­gat­ing the canopies of their trees.

With sig­nif­i­cantly lower water con­sump­tion, the sprin­klers must include a mist­ing sys­tem at night when the air is the cold­est, and the least amount of water will evap­o­rate.

The crown of each tree has its own noz­zle that sprays. The water then flows from the branches down to the ground beneath the tree.

The leaf sur­face man­ages to absorb very small par­ti­cles of water, and the result is vis­i­ble in a very short time. Water con­sump­tion is also sig­nif­i­cantly reduced com­pared to the clas­sic irri­ga­tion sys­tem, Pavlica con­cluded.


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