California nut growers resembled professional baseball catchers this year grabbing every curveball, changeup, and fastball thrown their way as changing weather patterns kept producers on their toes.

“It’s amazing the challenging weather we’ve gone through this season,” said Jim Peart, an almond grower in Arbuckle located on the western side of the Sacramento Valley.

Peart began harvest in late September and finished in early October.

“The good weather during most of the harvest period was a godsend,” Peart said.

Peart and his father Don are partners in Don Peart Ranch, a 400-acre almond operation in Colusa County. The father-son team grows Nonpareil (50 percent of the crop), plus the Butte, Monterey, Peerless, Winters, and Wood Colony varieties. The family harvests and hulls their crop.

Peart and other nut growers in the West battled wet and cold spring weather conditions. Peart also experienced cooler than normal summer temperatures.

As a result, the Peart’s Nonpareil crop is about 25 percent smaller this year at about 1,500 pounds per acre. Last year’s yields topped about 2,000 pounds/acre. Peart links the production shortfall to the wet bloom period.

“The cool, wet spring caused a wet bloom period which did not provide good pollinating weather as we’ve had in the past,” Peart said. “I was surprised by the smaller Nonpareil crop. I knew the crop would be off but didn’t think it would be this much.”

Peart is pleased with the low number of rejects, in the one-half of one percent range, from insects and other factors.

While the official farm production statistics were not immediately available, Peart expects the pollinator varieties will yield an average crop in the 2,000 to 2,300 pounds/acre range. The quality of the entire crop looks good.

Strange growing season

The strange growing season for Peart included only two days above 100 degrees this summer; instead 80s to low 90s were the norm. Three rain events totaling less than one-half inch in late August and September delayed the harvest even more.

“A rain front that moves through the west side of the Sacramento Valley is usually followed by several days of north winds which dry things up,” Peart said. “Instead the rain was followed by cool 70 and 80 degree weather with heavy dew each morning. It made for a long process to dry the nuts to take to the huller line.”

To accelerate the drying process, Peart attached a conditioner implement to the harvester to remove sticks and lay the nuts in a 3-foot band down the center of the tree row. The conditioner was purchased several years ago from Thomas Manufacturing Co. in Chico, Calif.

“Drying conditions for the almonds were less than ideal,” Peart said. The conditioner helped improve the drying process.”

On the pest and disease side, overall pressures were low on the Peart ranch. A miticide program with Agri-Mek provided good control. A first-ever fungicide application in July with the product Quash controlled alternaria, scab, and rust.

Soils on the Peart operation vary from sandy clay loam to clay loam. The average tree age is eight years; from two years to 15 years. Row spacing is 22 feet apart with 15 or 18 feet between the trees depending on the variety and soil.

Peart is slowly changing from the Lovell rootstock to the Krymsk rootstock due to high winds in the Sacramento Valley. A severe wind storm in the spring of 2008 destroyed about 2,000 Padre and Butte trees on Lovell rootstock on the Peart ranches; three quarter of the trees in one orchard.

Irrigation water use this year averaged 2.5 acre feet/acre, compared to 3 acre feet in 2009, due mostly to the extra rainfall this year.

The Pearts keep close tabs on irrigation management. Two years ago they invested in moisture sensor devices from PureSense to determine real time soil moisture content. The findings generated key information and brought needed changes toward better, long-term orchard health.

“I was probably irrigating too much in the spring and was under-irrigating in late June and early July,” Peart said. “It was amazing to learn how much water the trees used per day in the summer; more than 100 percent ET during late June and early July. I’m now better managing my water.”

Peart is now using more water. The trees are under less stress and better able to produce larger yields.

Cool temps boost walnut quality

Bob Lea grows English walnuts on 350 acres in Woodland in Yolo County, including the Howard, Chandler, Vina, and Tehama varieties. Lea kicked off the harvest in early October with hopes to conclude by month’s end.

“The Chandler yields appear larger this year, along with slightly larger Vina and Tehama yields,” Lea said. “The Howards are younger trees which developed good growth this year.”

Lea, a first-generation walnut producer, has grown walnuts for 30 years. He serves on the board of directors of Diamond Foods and as an alternate board member on the California Walnut Commission. Lea is an attorney specializing in civil law; purchasing a 40-acre ranch after completing law school.

The thermometer hit the 100 degree mark only twice this summer on Lea’s home ranch. Twenty days at 100 degrees plus is normal.

“The cooler temperatures will probably result in higher quality walnuts,” Lea said.

Lea’s walnut trees have Black walnut rootstock.

“Black walnut rootstock does better than the Paradox rootstock with the higher levels of boron in the water,” Lea said.

Pest and disease levels were average this year. Lea sprayed twice for the walnut husk fly; three times on one ranch. Puffer-based pheromone mating disruption kept the codling moth out of the Chandler variety.

Lea is always looking for new methods to improve the operation. He has inventoried every tree on two of his three ranches and continually tracks the trees.

“This process was a good learning lesson for us,” Lea noted. “You can see which practices work and which don’t work. You get to know your trees better. Each tree is individual and in a way has its own DNA. One-size-fits-all management does not always work.”

2010 California walnut production is expected to reach 510,000 tons, up 17 percent from 2009 (437,000 tons), according to the National Agricultural Statistics Service.

Lea is bullish on the industry’s future.

“It’s good to have a stable crop that the market knows will be supplied year after year,” Lea explained. “The walnut crop has become more stable over the years. We don’t have the large ups-and-downs that we used to have. Buyers worldwide can rely on our production to meet their needs. That’s a good thing.” 

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