State-of-the-Art Irrigation Management Leads to Rising Yields in California

According to the Sacramento Bee, mete­o­rol­o­gists fore­cast that the above-nor­mal tem­per­a­tures in California could worsen the state’s drought con­di­tion.

California is hav­ing a dan­ger­ously hot sum­mer. The National Oceanic and Atmospheric Administration (NOAA) sea­sonal out­look reveals a 33 to 60 per­cent chance that California’s weather will be hot­ter than usual for this period of the year.

With hot­ter weather con­di­tions on the hori­zon, olive pro­duc­ers seek solu­tions to man­age water sup­ply and opti­mize irri­ga­tion.

“At Cobram Estate, we firmly believe the food we eat and how we pro­duce it will deter­mine the health of peo­ple and the planet,” Leandro Ravetti, the company’s chief olive oil maker and co-chief exec­u­tive, told Olive Oil Times.

“During the past 20 years, Cobram Estate and its Oliv.iQ grow­ing sys­tem con­tin­u­ously imple­mented appro­pri­ate mea­sures from both an agri­cul­tural and indus­trial point of view to max­i­mize the effi­cient use of water,” he added.

Nathan Azevedo, founder and owner of WaterLab, told Olive Oil Times that installing and man­ag­ing irri­ga­tion sys­tems is one of the tough­est tasks fac­ing the Golden State’s farm­ers.

Azevedo sold most of the com­pany to GrowWest in 2021 but con­tin­ues to be involved as an owner. WaterLabs pro­vides tech­nol­ogy and con­sult­ing ser­vices for orchards and vine­yards in the Northern Sacramento region.

With active data, Azevedo said grow­ers are uniquely posi­tioned to develop, man­age, and mon­i­tor long-term water usage for suc­cess­ful har­vests.

He described how the ser­vice helps grow­ers decide when to start and how long to irri­gate.

“We use plant-based instru­ments com­bined with soil mois­ture sen­sors to give the entire above and below-ground view of the grow­ing sys­tem,” Azevedo said.

“Irrigation is com­plex,” he added. ​“Plant-based instru­ments, such as a pres­sure bomb, pro­vide an indi­ca­tor show­ing when a plant is stressed. Using this infor­ma­tion, grow­ers can irri­gate when the plant starts to become stressed.”

“The next step is below-ground sen­sors, such as the soil mois­ture probe. This indi­ca­tion helps grow­ers deter­mine how long to con­tinue irri­ga­tion,” Azevedo con­tin­ued. ​“You irri­gate to fill the soil pro­file to val­ues that no longer cause plant stress while being care­ful not to exceed the soil’s water hold­ing capac­ity.”

According to Azevedo, this holis­tic approach is nec­es­sary to max­i­mize yield while using lim­ited water resources as effi­ciently as pos­si­ble.

“Most peo­ple don’t use any instru­ments to help them make irri­ga­tion deci­sions, or they use only one instru­ment and neglect the oth­ers,” he said. ​“Some farm­ers use evap­o­tran­spi­ra­tion val­ues to help esti­mate crop water loss while for­get­ting that the evap­o­tran­spi­ra­tion cal­cu­la­tion doesn’t account for your soil’s water hold­ing capac­ity or infil­tra­tion rate.”

“If you apply water, you have cal­cu­lated to have lost, but that water applied isn’t able to pen­e­trate your clay soil or able to be held by your gravel soil, then your irri­ga­tion may be inad­e­quately reliev­ing the stress of your plants,” Azevedo added.

Some farm­ers may only use the pres­sure bomb to cal­cu­late stem water poten­tial and the stress of their plants while for­get­ting that the below-ground soil sys­tem is the media from which their plants retrieve water.

“Focusing on only the above-ground sys­tem can cause the soil to become too severely depleted to val­ues that are unre­cov­er­able in the hot sum­mer sea­son and lead to a con­stant state of stress to the above-ground plant,” Azevedo said.

“The oppo­site, irri­gat­ing too long and over­fill­ing the soil media to lev­els above field water hold­ing capac­ity, could lead to anaer­o­bic soil con­di­tions that cause root dis­eases to flour­ish and the decline of the above-ground plant,” he added.

Furthermore, some farm­ers only use soil probes to help make irri­ga­tion deci­sions and neglect how their manip­u­la­tion of soil mois­ture lev­els affects the stress of the above-ground plant.

With California’s cli­mate heat­ing up, new tech­nol­ogy unlocks the oppor­tu­nity for opti­miz­ing har­vests. Ravetti explained Cobram Estate’s key actions to max­i­mize water usage for robust yields.

“[We’re imple­ment­ing] irri­ga­tion sys­tems accord­ing to com­pre­hen­sive and exhaus­tive soil map­ping,” Ravetti said. ​“This helps deter­mine suit­able areas for devel­op­ment and most appro­pri­ate valve designs and shift arrange­ments.”

He added that the com­pany, one of the largest olive oil pro­duc­ers in the United States, has adopted sophis­ti­cated pres­sur­ized low-vol­ume irri­ga­tion sys­tems to min­i­mize inef­fi­cien­cies, state-of-the-art irri­ga­tion sched­ul­ing pro­to­cols and soil and tree mon­i­tor­ing sys­tems to eval­u­ate how irri­ga­tion affects each tree.

“[Cobram Estate also col­lab­o­rated] with envi­ron­men­tal groups to mon­i­tor and improve the envi­ron­men­tal per­for­mance of its prop­er­ties,” Ravetti said. ​“This included instal­la­tion and reg­u­lar mon­i­tor­ing of sev­eral piezome­ters [a device used to mea­sure liq­uid pres­sure] to pre­vent deep leach­ing.”

He added that Cobram Estate’s pro­pri­etary Oliv.iQ sys­tem com­bines sev­eral ele­ments to deter­mine and mon­i­tor day-to-day irri­ga­tion deci­sions.

“We uti­lize weather sta­tions and real-time cli­matic data to cal­cu­late evap­o­tran­spi­ra­tion of the sys­tem while we mon­i­tor soil mois­ture lev­els through probes and direct feel­ing method and tree con­di­tion through trunk sen­sors and pres­sure cham­bers,” Ravetti said. ​“All this infor­ma­tion is com­ple­mented by reg­u­lar satel­lite imagery and aer­ial pho­tog­ra­phy of our farms, allow­ing us to fol­low the evo­lu­tion of most com­mon crop growth indexes.”

“Because of the adop­tion of these more sus­tain­able and effi­cient agri­cul­tural prac­tices, as well as sig­nif­i­cantly higher yields (in gal­lons of oil per acre) than the indus­try aver­age, it is esti­mated our olive orchards pro­duce olive oil with a con­sump­tion of water 37 per­cent lower per ton of oil than the indus­try aver­age,” he added.

Traditionally, olives have been grown as a non-irri­gated crop well suited to Mediterranean dry­land. This demon­strates accept­able pro­duc­tion lev­els with lit­tle inter­fer­ence while pos­sess­ing the abil­ity to sur­vive pro­longed peri­ods of drought.

“Research has shown well-man­aged groves with proper irri­ga­tion pro­duce a con­sid­er­able increase in olive grove yields,” Ravetti said. ​“Olives as a crop, and extra vir­gin olive oil as a prod­uct, are per­fectly posi­tioned to play a crit­i­cal role in sus­tain­able food pro­duc­tion and ele­vate the adop­tion of sus­tain­able and healthy diets.”

“Additionally, when it comes down to water usage, olives main­tain one of the low­est water require­ments using 30 to 50 per­cent less water than most nut and fruit trees,” Ravetti added.

Integrated water man­age­ment encom­passes strate­gic irri­ga­tion tech­nolo­gies, water qual­ity and crop nutri­tion and may enable grow­ers to hit the water bulls­eye in their orchards, vine­yards and olive groves.

“It is, in our opin­ion, a holis­tic approach that uses mul­ti­ple instru­ments and sen­sors to help make the best irri­ga­tion man­age­ment deci­sions,” Azevedo said.

One of the key mea­sure­ments is the pres­sure bomb. The pres­sure bomb mea­sures how hard the plant is pulling on soil mois­ture. As soil water depletes, the harder the plant has to pull to retrieve mois­ture from the soil until it even­tu­ally pulls too hard, wilts and dies.

“It is like your blood pres­sure,” Azevedo said. ​“If your blood pres­sure is too high, your heart becomes stressed and has to pump too hard to retrieve blood from its veins and send it out through its arter­ies, even­tu­ally lead­ing to the pos­si­bil­ity of heart attack and death.”

“Low free-flow­ing blood and pres­sure bomb val­ues lead to healthy, happy plants and peo­ple,” Azevedo said. ​“Healthy, vig­or­ously grow­ing plants lead to the mon­ster crops that bring in the rev­enue to keep our farms in busi­ness.”

• The Sacramento Bee
• GrowWest