Experts Back Olives in a Hotter, Drier World

With another bil­lion peo­ple expected to live on the planet in the next three decades, Primo Proietti believes the most sig­nif­i­cant chal­lenge for the future will be to grow enough food.

“If we fail in cur­tail­ing green­house gas emis­sions, the ris­ing tem­per­a­tures on the planet’s sur­face will cause dev­as­tat­ing impacts on agri­cul­ture, reduce pro­duc­tive areas and slash crop yields,” the pro­fes­sor of agri­cul­tural and envi­ron­men­tal sci­ences at the University of Perugia, Italy, told Olive Oil Times.

“According to the Food and Agricultural Organization of the United Nations (FAO), within the next 30 years, the global pop­u­la­tion will exceed nine bil­lion,” Proietti added. ​“To respond to that, we need to increase food pro­duc­tion by at least 50 per­cent, expand­ing the cul­ti­vated areas and the yields per hectare.”

As a result, olive farm­ing may play a crit­i­cal role in the future of agri­cul­ture. Olive trees can sequester car­bon from the atmos­phere, sup­port soil health, pre­vent ero­sion and enhance bio­di­ver­sity by pro­vid­ing nat­ural habi­tats for numer­ous ani­mal species.

Sustainable agri­cul­tural prac­tices, such as using cover crops, min­i­mal tillage, and avoid­ing chem­i­cal pes­ti­cides and fer­til­iz­ers in organic farm­ing, can fur­ther enhance olive groves’ envi­ron­men­tal ben­e­fits.

As coor­di­na­tor of the European Union project Olive4Climate, Proietti and his team worked to eval­u­ate the car­bon bal­ance in Italian, Greek and Israeli farms.

They found that, on aver­age, pro­duc­ing one liter of extra vir­gin olive oil sequestered six kilo­grams of car­bon diox­ide com­pared with the 3.4 kilo­grams emit­ted dur­ing its pro­duc­tion.

“By adopt­ing envi­ron­men­tally sus­tain­able cul­ti­va­tion mod­els, olive oil can even have a neg­a­tive car­bon foot­print,” Proietti said. ​“Olive grow­ing can mit­i­gate cli­mate change since the car­bon seques­tra­tion occur­ring in the olive grove sys­tem is greater than the emis­sions of the entire sup­ply chain.”

“This is a result of sig­nif­i­cant envi­ron­men­tal inter­est and can, there­fore, have a con­sid­er­able pos­i­tive impact on con­sumer choices and can con­se­quently gen­er­ate sig­nif­i­cant added value for the oil,” he added.

The E.U.-backed project pro­duced a man­ual to help improve the car­bon bal­ance by reduc­ing emis­sions and increas­ing the car­bon sequestered in plants and soil.

According to Proietti, the promis­ing olive tree-related car­bon credit mar­ket might fur­ther boost olive trees’ sig­nif­i­cance when com­bat­ing cli­mate change.

Still, the most recent olive har­vests and the impacts of cli­mate change have shown to the global com­mu­nity the severe chal­lenges olive pro­duc­tion has to face in cur­rent times.

“The olive tree is a highly resilient tree,” Adriana Bruggeman, a researcher and asso­ciate pro­fes­sor at the Cyprus Institute, told Olive Oil Times. ​“When it comes to pro­duc­tion, irri­ga­tion facil­i­ties, reg­u­lated access to water resources and sus­tain­able prac­tices can prob­a­bly offer the olives good pro­tec­tion from events such as drought.”

Besides the cor­rect and sus­tain­able man­age­ment of the grove, water avail­abil­ity for irri­ga­tion and best prac­tices are top pri­or­i­ties for cur­rent and future olive farms.

“Climate change is caus­ing both a decrease in rain­fall dur­ing the sum­mer (cur­rently by 2.5 per­cent) and higher water con­sump­tion by plants due to increased evap­o­tran­spi­ra­tion,” Proietti said.

That adds to more sig­nif­i­cant water loss from the soil through evap­o­ra­tion and tran­spi­ra­tion due to ris­ing tem­per­a­tures, which increases irri­ga­tion needs.

“In the Mediterranean, an increase in irri­ga­tion require­ments of almost 20 per­cent is esti­mated for the com­ing decades,” Proietti said.

“Water resources will be less,” Bruggeman added. ​“Today, we irri­gate many crops. In the future, some might even switch to allo­cat­ing more for olive trees and less for tree crops that are less drought tol­er­ant.”

Modern irri­ga­tion tech­nolo­gies and pro­ce­dures can sig­nif­i­cantly improve effi­ciency. In Cyprus and many other olive-pro­duc­ing coun­tries, advanced weather mon­i­tor­ing sys­tems are increas­ingly used to bal­ance irri­ga­tion and max­i­mize the ben­e­fits of water use.

“The appli­ca­tion of a deficit irri­ga­tion strat­egy, already exper­i­mented with olive groves and vine­yards, increases water use effi­ciency as it avoids exces­sive soil mois­ture while pre­serv­ing water for the veg­e­ta­tive-pro­duc­tive cycle where water most improves pro­duc­tive per­for­mance,” Proietti said.

He added that soil mois­ture in olive groves should meet about 70 per­cent of the trees’ water needs at essen­tial moments in tree devel­op­ment, includ­ing meso­carp growth, pulp gen­er­a­tion and fruit set­ting.

“It should be at about 30 to 40 per­cent dur­ing phases more directed towards the hard­en­ing of the pit and veg­e­ta­tive activ­ity,” Proietti said. ​“In this man­ner, 30 to 50 per­cent water sav­ings can be achieved with no exces­sive reper­cus­sions on pro­duc­tion.”

Other sig­nif­i­cant approaches include irri­gat­ing at night to reduce evap­o­ra­tion losses, main­tain­ing the soil and enrich­ing it with organic mat­ter.

“[These mea­sures] improve water reten­tion capac­ity and reduce sur­face water runoff in sloped ter­rains, thus increas­ing soil stor­age, by appli­ca­tion of cover crop­ping in win­ter and sub­se­quent green manur­ing at the begin­ning of spring,” Proietti said.

“If the soil is man­aged through per­ma­nent cover crop­ping, it is pro­tected from extreme tem­per­a­ture vari­a­tions and exces­sive evap­o­ra­tion by exploit­ing the mulching effect of grass clip­pings,” he added.

In the con­text of olive cul­ti­va­tion, mulching involves cov­er­ing the soil around the olive trees with a layer of mate­r­ial, which can be organic or inor­ganic.

The goals include mois­ture con­ser­va­tion, reduc­ing weed growth by block­ing sun­light, reg­u­lat­ing soil tem­per­a­ture, pro­tect­ing roots from weather extremes and improv­ing soil health when organic mate­ri­als are used and slowly decom­pose.

“Mowing of the annual veg­e­ta­tion cover such as weeds and leav­ing the mowed veg­e­ta­tion on the field to dry gen­er­ates a healthy mulch cover,” Bruggeman said.

“This is a good prac­tice to reduce evap­o­ra­tion losses, thereby reduc­ing irri­ga­tion water demand,” she added. ​“It also improves the soil’s organic con­tent and soil health, which cre­ates bet­ter soil-water stor­age and makes the trees more resilient.”

Besides sav­ing water, Bruggeman said advanced irri­ga­tion man­age­ment can improve oil qual­ity. Providing too much water to the olives right before the har­vest can decrease oil yield in the olives and lower qual­ity.

Away from opti­miz­ing irri­ga­tion, Bruggeman said extreme tem­per­a­tures and heat­waves, espe­cially ones that coin­cide with olive tree flow­er­ing, are chal­lenges that olive grow­ers in Cyprus and else­where must also face.

“What we are going through in Cyprus and prob­a­bly through­out the Mediterranean basin is a grow­ing unpre­dictabil­ity of weather; that is how we can see that cli­mate is chang­ing,” Bruggeman said.

“In these times, the olive tree, some of its char­ac­ter­is­tics such as being drought-tol­er­ant, still make it one of the best agri­cul­tural land uses,” she con­cluded.