Water Efficiency, Sustainability Must Go Hand in Hand in the Olive Grove

The National Agency for Meteorology in Spain (Aemet) has warned local insti­tu­tions and farm­ers that warm tem­per­a­tures and the lack of rain that started in March will per­sist through April.

Aemet said pre­cip­i­ta­tion is ten times below aver­age so far this year. Reservoirs in Spain reach, at best, half capac­ity, while farm­ers in the south are resort­ing to irri­ga­tion at an unusu­ally-high vol­ume for the sea­son.

According to experts, a sus­tain­able and inno­v­a­tive approach to olive farm­ing is the only way to cope with a quickly chang­ing cli­mate.

“Adaptation strate­gies and tech­nolo­gies can make a sig­nif­i­cant dif­fer­ence in mit­i­gat­ing the effects of cli­mate change and ensur­ing the sus­tain­abil­ity of the olive groves in the long term,” Ramzi Belkhodja, admin­is­tra­tor of the International Center for Advanced Mediterranean Agronomic Studies (CIHEAM) Zaragoza chap­ter of the plant pro­duc­tion, health and breed­ing depart­ment, told Olive Oil Times.

CIHEAM Zaragoza and the International Olive Council are pro­mot­ing a spe­cific course next September focussing on olive grow­ing, sus­tain­abil­ity, soil health, tech­nolo­gies and poli­cies. Well-known inter­na­tional researchers will hold lec­tures.

“Farmers are becom­ing increas­ingly aware of what cli­mate change may bring, so I believe that if the infor­ma­tion is avail­able, they will be the first to adopt cli­mate change mea­sures,” Hélder Fraga, a lec­turer at the course and researcher at the University of Trás-os-Montes and Alto Douro’s agri­cul­tural and life sci­ence research and tech­nol­ogy cen­ters, told Olive Oil Times. 

“It is dif­fi­cult to gen­er­al­ize about the aware­ness of farm­ers regard­ing the cur­rent cli­mate change sce­nario as it varies from region to region and farmer to farmer,” Belkhodja added.

“However, it is impor­tant to note that many farm­ers are expe­ri­enc­ing the effects of cli­mate change first­hand, such as unpre­dictable weather pat­terns and water scarcity, which can affect their crop yield and prof­itabil­ity,” he said.

While a basic under­stand­ing of the impacts of cli­mate change has spread among grow­ers at var­i­ous lat­i­tudes, adap­ta­tion strate­gies are often faulty or out­right miss­ing.

“Traveling around the world and study­ing how olive grow­ers are act­ing in sev­eral regions, I see how wor­ry­ing about water scarcity does not always trans­late into appro­pri­ate action,” Arnon Dag, a fruit tree researcher at the Israeli Ministry of Agriculture, told Olive Oil Times.

He added that research could help irri­gated and rain­fed olive groves, which are more exposed to changes in pre­cip­i­ta­tion pat­terns.

“Apart from sup­ple­men­tal irri­ga­tion, options for inter­ven­tions on rain­fed orchards are lim­ited,” Dag said. ​“One approach we are work­ing on in Israel is to bal­ance the den­sity of the olive tree canopy with water avail­abil­ity.”

“As evap­o­ra­tion hap­pens through the leaves, if grow­ers can mon­i­tor it, they can adjust the canopy,” he added. ​“They can reduce its vol­ume when needed to cur­tail evap­o­ra­tion and main­tain the health of the tree even when rain­fall scarcity sets in.”

Thermal imag­ing tech­niques allow researchers to mea­sure the trees’ water stress. Other tools enable them to esti­mate the right canopy vol­ume and to what extent prun­ing is required.

Researchers rec­om­mend that grow­ers with rain­fed groves begin the tran­si­tion to drip irri­ga­tion where pos­si­ble.

“These are the two main con­sid­er­a­tions,” Dag said. ​“The first is effi­ciency in water use, and the sec­ond is low-qual­ity water.” 

He added that some advanced tech­nolo­gies and pro­to­cols already allow for treat­ing sewage water pro­duced by urban areas and recy­cling it for farm­ing.

“A nine-year study has shown that cor­rectly fil­tered waste­water can be used for the irri­ga­tion of olive groves,” Dag said. ​“The research has shown no dif­fer­ence in the qual­ity of the prod­uct when you com­pare an orchard irri­gated with fil­tered sewage waters to one fed by fresh­wa­ter.” 

“We have even seen that recy­cled water might even con­vey bet­ter results in terms of yields,” he added. ​“We are study­ing the phe­nom­e­non, but one hypoth­e­sis for this to hap­pen is in the ben­e­fi­cial micro-organ­isms and other sub­stances that are to be found in those fil­tered waters.”

Saving water as much as pos­si­ble and using only what is needed are goals within reach for most olive grow­ers. 

“One thing that struck me in many irri­gated orchards world­wide is the absence of water meters,” Dag said. ​“Many grow­ers just open irri­ga­tion and sus­pend it when they feel it is time. But how can you make pre­ci­sion irri­ga­tion with­out some­thing so sim­ple as a water meter?”

To choose the cor­rect irri­ga­tion vol­umes, evap­o­tran­spi­ra­tion mon­i­tor­ing and on-field sen­sors are cru­cial tools to help olive grow­ers to irri­gate their groves cor­rectly.

The issue of water scarcity is affect­ing invest­ments in olive pro­duc­tion. Belkhodja empha­sized how ​“olive farm­ers are vul­ner­a­ble to water scarcity, which can greatly impact their crop yield and over­all prof­itabil­ity.” Hence the need to share knowl­edge and tech­nolo­gies with olive grow­ers.

“The most impor­tant issue to con­sider is the timely plan­ning of adap­ta­tion mea­sures,” Fraga con­cluded. ​“For exam­ple, when plan­ning a new vine­yard or orchard, grow­ers should look to the pro­jec­tions for the next 30 years and con­sider using more adapted vari­eties.” 

• CIHEAM