The California almond industry is chock-full of dreamers — those who paved the way toward an all-time record 2-billion-pound crop expected this next crop year, and those who aspire to push yields upwards to 5,000-pounds per acre in the future.
These visions have placed the California almond industry at the top of its game; an industry clearly in the driver’s seat charting its own future course.
“We once believed achieving a 2-billion-pound California almond crop was a distant dream but now it’s a reality,” said Bob Curtis, associate director for ag affairs and production research manager with the Almond Board of California in Modesto, Calif.
“Our industry must grow, sell, and promote California almonds differently than we have in the past. More productivity generates challenges.”
Curtis chaired an almond production workshop entitled, “Growing a 2 billion-pound crop…it’s a game changer,” held during the 2011 Almond Industry Conference in Modesto, Calif., in December.
Curtis says California almond yields have doubled over the last 20 years.
“A good yield has increased from 2,000 kernel pounds per acre in the 1980s to 3,000-plus-pounds per acre today,” Curtis told the standing-room-only crowd. “In the 1980s, a ton of meats at a dollar a pound was happiness; a ton was the gold standard.”
Three veteran almond farm advisors discussed significant research strides achieved over the last three decades which led to higher yields; plus the prospects to one day achieve 5,000-meat-pound yields.
The almond experts included University of California Cooperative Extension (UCCE) Emeritus farm advisors John Edstrom of Colusa County and Mario Viveros of Kern County, plus UCCE IPM entomologist Walt Bentley of Parlier.
Combined, these UCCE specialists have nearly 100 years of experience in the California almond industry .
Edstrom ties monumental yield increases in recent decades to precision irrigation , high-density tree planting, minimum and machine pruning techniques, and soil modification and amendments. Flood-irrigated orchards are no longer the norm.
“There are not too many orchards designed today for flood irrigation,” Edstrom said. “There is not much ‘click-clack-click’ of the aluminum pipe and impact sprinklers around anymore.”
Efficient micro irrigation began in California almonds in the 1960s, but adoption was slow and finally accelerated in the 1980s. Micro irrigation helped reduce water use in drought-prone California and improved water efficacy for trees. A double hose drip system is most common statewide.
“Precise irrigation management starts with evapotranspiration (Etc) as a general guideline but also use probes for soil monitoring, a dendrometer to measure tree growth and irrigation sufficiency, and a pressure chamber to measure tree water stress,” Edstrom said.
Surprisingly, subsurface drip irrigation (SSDI) can be a successful delivery technique in almond orchards, Edstrom says. An estimated 7,000 acres of almond trees are profitably watered with SSDI in the Sacramento Valley.
About 35 years ago, Edstrom first set foot in an almond orchard. His Chico-area home sat in a 50-tree-per-acre orchard with towering 50-foot-tall almond trees. The standard tree spacing in those days was 30-by-30 feet.
Today’s high density-planted orchards can include up to four times more trees, Edstrom says. In the Sacramento Valley, spacings of 15-by-22 and 16-by-22 are common today. In prime soils, 18-by-24 and 20-by-24 spacings are preferred.
“High-density plantings fill the canopy faster and yields are dramatically higher in the third, fourth, and fifth year,” Edstrom said. “Years ago we did not harvest third year crops — that’s not the case anymore.”
Soil modifications increase yields. The slip plow and other equipment effectively mix the soil layers to create improved root growth plus better oxygen and water infiltration.
Pruning has evolved from heavy pruning to moderate or minimal pruning depending on the soil type.
These research-developed findings by this researcher trio and others have sparked high yield increases. Yet dense, high-vigor orchards have generated production obstacles including more disease problems (alternaria leaf spot, rust, scab, and hull rot); ceratocystis canker-related shaker damage; and delayed crop maturity and hull drying tied to increased shading and stagnant air.
“Increased disease requires more fungicides and higher costs,” Edstrom said. “I know several growers this last season who applied seven fungicide sprays. If a single spray costs $50 per acre then that’s $350 an acre. That’s more than the cost of bee pollination.”
Mario Viveros moved to Kern County in 1979 when statewide almond acreage totaled about 63,100 acres; about 60,500 bearing. Today, California farmers grow almonds on about 750,000 bearing acres in 16 counties.
Kern is the largest almond-producing county in the state, in order, by Fresno, Stanislaus, and Merced counties. Today, California almond growers produce an 80 percent chunk of world production.
In 1979, Kern County almond yields averaged about 1,400 pounds/acre.
“A good grower was happy with 1,600 pounds,” Viveros said.
Production costs averaged $900 to $1,100 per acre. Frost risk was minimal in most areas and diseases were almost nonexistent. The primary problem was insects.
“The navel orangeworm ate our cake,” Viveros said.
The 2,000-pound dream
At local coffee shops, Viveros recalls growers’ verbal chatter on the dream of achieving 2,000-pounds per acre.
Almond research including regional variety plots, pruning, noninfectious bud failure, and post-harvest irrigation brought the dream to fruition. Regional variety plots in 1974, 1986, and 1993 assessed variety performance under commercial conditions.
“We learned Nonpareil variety yields increased when planted in a 1:1 arrangement,” Viveros said. “Bloom overlap was extremely important. We learned that Butte had tremendous yield potential.”
As a result of the regional variety trials, the varieties Solano, Winters, Sonora, and Padre were released.
“I didn’t think Padre would be a highly yielding variety but it was extremely productive.”
Noninfectious bud failure studies assessed Nonpareil and Carmel clones.
“The Nonpareil clone 2-70 had very low bud failure potential,” Viveros said. “Most nurseries today have adopted the Clone 2.”
Over the decades, entomologist Walt Bentley says pest management research has reduced nut losses statewide which translate into higher yields. Improved winter orchard sanitation has significantly reduced navel orangeworm (NOW) losses — 8.8 percent in the late 1970s to 0.68 percent for the 2011 crop.
As California almond acreage edges closer to 1 million acres, Bentley is concerned about increased pest problems. NOW is a significant pest in almonds, walnuts, and almonds. Different nut types are planted closer than ever before. This will make insect control more difficult.
Bentley’s preferred choice to reduce insect infestation and damage is winter sanitation practices.
“We are getting to a point where navel orangeworm control requires an area management approach,” Bentley said. “The most effective control of NOW is winter sanitation. The lack of sanitation is the best threshold for NOW damage.”
Precise timing of insecticidal applications is also important for NOW control. A three-day late treatment can reduce NOW control by 20 percent.
Bentley will retire from UC in June.
In closing the workshop, Viveros asked and answered the almond industry’s 500-pound gorilla question. Is a 5,000-pound per acre goal achievable at a low cost?
“I doubt it,” Viveros said.
“High density plantings may not generate 5,000 pounds per acre. To achieve higher yields, tree density needs to fit the soil and soils should be free of water penetration problems. A well-designed irrigation system is critical while following good irrigation and fertilization practices.”
It is very important to be a good horticulturist, Viveros says.