The first shake of grower Matthew Efird’s 80 acres of Serr walnuts, completed the first week of September, did not produce the yield results he had hoped.  

Over the last four to five years, his 20-year-old-plus Serr trees have consistently produced a respectable 6,200 to 6,600 pounds (in-shell) per acre, he reports. This year, yields from the first shake were down more than 8 percent from normal.  

“While looking at the nut set in late spring, it appeared that production would be off a little bit this year, but I never imagined the yield would be off this much,” Efird says.

Unfortunately, nut quality was also off significantly.

Typically, the more desirable, higher-value, light-colored nut meats represent an average of about 75 to 80 percent of his walnut crop. This year, the figure for his first-shake Serrs fell to 47 percent.

“It’s very frustrating to see an unanticipated drop in quality,” says the 39-year-old Efird, who also grows 80 acres each of Tulare and Chandler walnuts.

“We’ve never had issues with such low light meat numbers as we had with our Serrs this year,” he explains. “If we had known the quality would be this low, we would have focused on a single shake and harvest, and saved the expense of the second shake.”

Efird is a fifth-generation farmer and vice president of Double E Farms with his father Russel. They also grow almonds, raisins, and wine grapes on their 1,300-acre ranch located near Caruthers, Calif.

Efird isn’t sure why Serr yields and quality came up short. His crop management and farming practices were the same this year.

This season, as usual, he treated the walnut orchards with sunscreen to minimize sunburn during nut fill when the nut is most vulnerable to heat which can darken but meat color. He applied Surround around the perimeter of the Serr, Tulare, and Chandler walnut fields by ground on June 1. The next day he treated the Serr trees with Pure Shade by helicopter.

Also, since the Serr variety can be highly-susceptible to pistillate flower abortion, Efird ground applied the growth regulator Re-Tain on March 19 to help prevent nut-producing flower loss shortly after bloom.

“We have participated in several years of University of California Cooperative Extension field trials on this material so we are very comfortable with our application rate and timing,” Efird explains.

He had adequate good quality water, mainly from wells, to meet the needs of his micro sprinkler-irrigated trees. In fact, the surface water he received this season, for the first time in the last five years, helped leach out some salts which had accumulated in the soils during the drought.  

In addition, two years ago he adjusted his fertilizer program to include more liquid humus and several other micro nutrients to help mitigate increased salt levels in the soil.

“This change produced good results last year and I assumed they would continue,” Efird says.

Now, he’s speculating about the cause of this year’s disappointing Serr performance. Perhaps it reflects the combined effects of five years of drought, along with a spell of hot weather back in July. Due to pressure from a neighbor’s field, mites flared up unexpectedly in one corner of Efird’s Serr field. Yet the nut grades from this area were no different than the rest of the field.

“I’ve heard reports that other growers are experiencing lower yields and quality with Serrs this harvest season,” Efird says. “This doesn’t make me feel any better, but it indicates that the problems with our Serr crop this year aren’t due to our farming program which until now has been successful.”

Looking at his Tulare walnut crop, he says other area growers began harvesting Tulares in mid-September. Efird will hold off shaking his Tulares which are still coming into production until next year when yields should be high enough to justify the cost of a full harvest crop. However, he plans a sanitization shake of the trees this coming winter.

And for his Chandlers, Efird is encouraged about the yield prospects for his seven-year-old trees.  He finished spraying Ethephon from ground level on Sept. 13 in an effort to accelerate hull split and boost quality by allowing for more uniform maturity and harvest. On Aug. 20, he applied the same material by ground to his Serr trees.

Yields of his uncle’s 18-year-old Chandlers across the street from the Efirds’ operation are expected to be higher than last year, following a good crop set this spring.  This heavier set reflects changes in his uncle’s fertilizer program, he says.

“Production of our seven-year-old Chandlers look phenomenal for their age,” says Efird, who started the harvest on Sept. 26. “These younger trees had a lot of limb breakage earlier in the season from the heavy crop load.”