Good growing conditions, water availability, and potential lower production costs make the Southern California and Arizona low desert potential ground for pomegranate and olive production.
California’s San Joaquin Valley is the U.S. production Mecca for an estimated 22,000 acres of pomegranates and about 40,000 acres of olives.
Several desert plantings are taking root. Very small pomegranate plantings are located in California’s Riverside County in Blythe and other areas, according to Tom Shea, staff research associate, University of California Cooperative Extension, Riverside County, Moreno Valley, Calif. “We are getting lots of questions about pomegranates,” Shea said.
A two-year-old, 50-acre pomegranate planting is located just south of the U.S.-Mexico border near San Luis, Sonora, Mexico, according to Glenn Wright, associate research scientist with the University of Arizona, Yuma.Wright says there is also a pomegranate planting in Yuma County.
A super high density olive planting is located near Niland in Imperial County. Another is in Yuma County, Wright says. A boutique olive farm and mill is located in Queen Creek near Phoenix. Grower Gary Wood uses water from his shrimp operation in Gila Bend, Ariz., to grow 500 acres of table olives.
Wright discussed pomegranates and olives during an alternative desert crop seminar at the 2010 Southwest Agricultural Summit in Yuma.
He gave out high passing marks for the desert’s low humidity, high heat, water supplies, soil types and pH, all important criteria for successful pomegranate and olive production.
The pomegranate continues to gain a foothold with health-conscious consumers seeking foods and beverages with high levels of antioxidants (polyphenols). The fruit contains sodium, potassium, iron, and phosphorus. Pomegranates are about 80 percent water, and are consumed as fresh fruit and as a juice beverage.
“The pomegranate is like the Gatorade of the fifth century,” Wright said.
Among the major SJV pomegranate production areas are Kern County with about 15,000 acres and Fresno County with about 5,000 acres, according to 2008 county agricultural commissioner reports.
SJV pomegranates are hand-harvested in the late summer and fall. The early harvest begins in August for the small-to-medium, apple-sized Granada and Foothill Early varieties. The tart-flavored fruit has pink-to-red-colored skin. The varieties are susceptible to stem end decay; a problem Wright believes would be less severe in the desert.
Wonderful and Early Wonderful varieties are harvested during October through December in the SJV. The medium-to-large, orange-sized fruit is sweeter than the early varieties. Skin colors range from a deep glossy pinkish red to crimson. All early and late pomegranate varieties for fresh-market consumption are shipped ripe and ready to eat.
Wright says the Early Wonderful variety is more susceptible to stem end decay. The Wonderful variety has more branches which can scar the fruit in high winds. About 80 percent of California-grown pomegranates are the Wonderful variety.
Pomegranate fruit is hand-harvested weekly for the fresh market. Production varies from 300 boxes to 800 boxes/acre.
A Madera, Calif., grower has developed a mechanical pomegranate harvester. Similar to a mechanical grape harvester, the unit harvests pomegranates trellised like grapevines. He picks a percentage of the fruit for the fresh market and mechanically harvests the rest for the juice market. “The desert heat never gets too hot for pomegranate production,” Wright said.
Cold temperatures should not dip below 12 F; not a concern in the desert. High humidity can cause the fruit to split. The desert generally has low humidity. Later-season varieties may be better suited for the desert due to higher humidity during the summer monsoon season, Wright says. The small pomegranate tree requires about 30 inches of water through drip irrigation annually and about 45 inches with flood irrigation. Regular irrigation is critical as a missed irrigation can cause fruit splitting.
The saline tolerance is up to 2,700 parts per million of salt. Pomegranates prosper in well drained, sandy or loam soils. The pH tolerance is about 8.8 percent.
However Wright believes warmer desert temperatures could reduce fruit coloration. Consumers prefer brightly-colored fresh fruit.
“This could be a reason why pomegranates are not (widely) grown in the desert,” Wright said. “There may be ways to solve that problem through new varieties.”
Wright does not foresee disease problems with pomegranates in the desert. Thrips and mites could pose pest pressures.
The USDA germplasm repository is studying three promising pome varieties worth consideration in the desert, says Wright.
Kara bala miursal produces a large, red fruit speckled with sweet, tart arils (juice sac). The harder seed may not be popular with consumers if consumed as fresh fruit. Parfianka is a good tasting sweet/tart variety with a deep color and flavor similar to the Wonderful. The small seeds are more pleasant to eat. The fruit has softer membranes. Smith is an early-ripening, high-juice variety with a higher brix level and a deep red color with soft seeds.
The United States ranks fifth in world fresh pomegranate production behind the leaders — Iran, India, China and Turkey. The pomegranate was one of the world’s first cultivated fruits over 4,000 years ago. The fruit, native to Central Asia and Iran, was brought to the United States by Spanish explorers.
Olives, a 6,000 year-old crop native to Asia Minor, were also brought to the U.S. by the Spaniards. Over 150 primary varieties exist. About 95 percent of global olive production is centered around the Mediterranean Sea.
In the European Union about 200 trees planted per acre produce more than 50 gallons of oil per acre. New high density plantings (600 and more trees per acre) popular in California, Chile, and Australia yield about 200 gallons per acre.
“The United States is the third-largest olive oil consumer in the world yet we grow one-tenth of the olives we consume,” Wright said. “The U.S. would have to plant 300,000 acres of olives for oil to meet our own domestic consumptive demands. Opportunities exist for more locally-grown, high-quality olives for oil.”
Ninety-nine percent of U.S. olive production is centered in California’s Central Valley, plus some acreage around the state’s coastal area. Arizona and Texas produce 1 percent.
According to the California Department of Food and Agriculture, harvested olive acreage totaled about 30,000 acres in 2008. Leading counties included Tulare, Glenn, Tehama, San Joaquin, and Butte. Wright believes the low desert is a ripe location for olive production.
“Olives like drier climates and excessive heat is not an issue,” Wright said. “Olives are an alternate bearing crop. That is a problem we think can be managed through proper pruning and fertilization.”
High winds can reduce olive fruit set so less windy areas are recommended. Cold temperatures, insects, and disease are not issues in the desert.
A growing trend in California olive production is high density plantings (200-350 trees/acre) and super high density (SHD) plantings (670-907 trees/acre); all mechanically harvested.
Would SHD olive plantings work in the desert?
“We don’t know the answer to that question yet,” Wright said. “Fast growing conditions in the desert would create high vigor which would require more pruning with the closer-spaced trees. Vigor control is important to improve fruit quality.”
An olive oil cost study conducted by Karen Klonsky, University of California Cooperative Extension specialist, says production costs at $9 per gallon would require about 195 gallons of oil/acre to break even. Costs at $15/gallon would require about 215 gallons/acre to break even.
Wright says seven- to 10-year contracts are available from $10-$18 per gallon.
Popular varieties in California SHD plantings include Arbequina, a large-volume, high-quality olive variety that is not very stable in storage, Wright says, but fits well into the SHD system. Arbosana is a later-bearing variety which produces high quality oil. Koroneiki produces a smaller olive with a peppery taste good for oil blending.