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Posts Tagged: walnuts

A nutty idea: A little stress could be good for walnuts

When it comes to watering walnuts, most California growers believe you need to start early to keep trees healthy and productive throughout the long, hot summer. But according to striking results from a long-term experiment in a walnut orchard in Red Bluff, growers can improve crop production if they hold off irrigation until later in the season and directly measure their trees' water needs.

The findings from researchers at the University of California may help farmers optimize water use.

“It's a game-changer,” said walnut grower Hal Crain, who welcomed researchers on to his orchard to test irrigation optimization. “It's clear to me you can improve nut quality and yield by applying water based on what the tree wants and needs, rather than just watering when it's hot outside and the soil is dry. That's a big deal for walnut growers and for the entire agricultural industry.”

Hal Crain's family has been growing walnuts for 55 years.

 Changing the paradigm

Crain is a second-generation farmer whose family has been growing walnuts in Butte and Tehama counties for 55 years. Like most walnut farmers, Crain had always started irrigating in early to mid-May when the days grew warmer and the trees sprouted leaves.

“That's standard practice for probably 90 percent of California's walnut growers,” said Crain, walking amid his trees on a sunny afternoon. “The theory is that when you irrigate early, you preserve the deep moisture in the soil that trees need to survive the heat of summer.”

But that's not how it works, the research shows. Instead, trees that grow in saturated soil early in the season don't develop the deep roots they need to thrive.

“With all the water right there at the surface, the lower roots suffer,” explained Bruce Lampinen, UC Cooperative Extension orchard management specialist with the UC Davis Department of Plant Sciences. “Trees end up with a very shallow root system, which doesn't serve them well as they try to extract moisture from the soil later on.”

Lampinen has long suspected that walnuts were getting too much water in the spring.

“A lot of the symptoms we see like yellowing leaves and various diseases can all be explained by overwatering,” said Lampinen.

So Lampinen did what scientists do: He set up an experiment. Five years ago, with funding from the California Walnut Board and the U.S. Department of Agriculture, he joined forces with Ken Shackel, a plant sciences professor with UC Davis, and Allan Fulton, an irrigation adviser with UC Cooperative Extension. Together, they led a team of scientists testing irrigation on Crain's ranch. 

“Hal is an exceptional partner,” Fulton said. “Farmers have a lot to accommodate when they host an experiment like this, with researchers going in and out of the orchard at all hours. He had to work around our people and the timing of our water treatments. He's always eager to experiment with technology and learn new things, and he shares what he learns with other growers. Hal completes the circle.”

Tough nut to crack

When is the best time to irrigate? Researchers say the trees hold the answer. Scientists use pressure chambers, which are air-pressure devices that measure a leaf or small shoot to gauge how hard the plant is working to pull moisture from the soil.

“Just because the soil looks dry doesn't mean the plant is suffering,” said Shackel, who specializes in plant physiology. “Pressure chambers let you ask the tree how it's feeling — sort of like taking a human's blood pressure — which is a much more accurate way to measure a plant's water needs.”

Professor Ken Shackel and Cooperative Extension Specialist Bruce Lampinen test pressure chamber in UC Davis walnut grove.

For the last five years, the team has been applying different water treatments to five blocks of trees. One block is getting standard, early irrigation. Crain's orchard managers begin irrigating the other blocks when the trees reach different levels of water stress based on pressure-chamber readings.

The trees that experience moderate stress are doing the best. Their irrigation usually starts in mid-to-late June, several weeks later than when standard watering begins.

“You can tell just by looking at that block that the trees are healthier,” said Crain, standing beneath a canopy of lush, green trees. “And, we're starting to see greater yields and better nut quality.”

Translating the research

The research is helping scientists advise farmers on irrigation.

“My biggest take-away is knowing when to start watering is a really important factor to the health of your trees,” Lampinen says.

Pressure chambers — sometimes called pressure bombs — can cost more than $3,000, and high-tech versions are under development.  

“I tell growers a pressure bomb would pay for itself even if you just used it once a year to determine when to start watering,” Lampinen said.

Crain is certainly convinced.

“When you irrigate based on your trees' needs, you optimize water,” Crain says. “I'm not using less water overall, but the water I do use is producing more food. That's good news for everyone.”

This story was originally published in the Fall 2018 issue of Outlook Magazine, the alumni magazine for the UC Davis College of Agricultural and Environmental Sciences. 

Posted on Tuesday, November 6, 2018 at 9:20 AM
Focus Area Tags: Agriculture

UC Cooperative Extension farm advisors launch “Growing the Valley” podcast

UCCE advisors Phoebe Gordon, left, and Luke Milliron are the hosts of the new 'Growing the Valley' podcast.

A new UC Cooperative Extension podcast that focuses on growing orchard crops in the San Joaquin and Sacramento valleys is now available free at http://growingthevalleypodcast.com, Apple iTunes and Google Play Music. The hosts are Phoebe Gordon, UCCE orchard systems advisor in Madera and...

Posted on Friday, June 8, 2018 at 9:29 AM
Tags: Almonds (6), Figs (1), orchard (1), Peaches - Cling (1), Pistachios (3), podcast (1), Prunes (2), Walnuts (20)
Focus Area Tags: Agriculture

New cost and return study for walnuts released by UC Agricultural Issues Center

The UC Agricultural Issues Center has released a new study on the costs and returns to establish an orchard and produce walnuts in the northern San Joaquin Valley.

This study assumes a hypothetical farm size of 100 contiguous acres that is farmer owned and operated. Sixty acres are being established to walnuts and 35 acres are planted to other permanent or annual crops. The walnut orchard is planted on a 24-by-24-foot spacing using three-quarters inch caliber nursery grafted trees on a Paradox rootstock. The walnut trees are a late leafing, lateral bearing variety. 

Input and reviews were provided by UC Cooperative Extension farm advisors and other agricultural associates. The authors describe the assumptions used to identify current costs for the walnut crop, material inputs, cash overhead, and non-cash overhead. Ranging analysis tables show net profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.

The new study is titled: "Sample Costs to Establish an Orchard and Produce Walnuts, in the San Joaquin Valley North – 2017"

This study and other sample cost of production studies for many commodities are available for download on the UC Davis Department of Agricultural and Resource Economics website at http://coststudies.ucdavis.edu.

For additional information or an explanation of the calculations used in the studies, contact Jeremy Murdock at the Agricultural Issues Center at (530) 752-4651, jmmurdock@ucdavis.edu, or UCCE advisors Joe Grant, jagrant@ucanr.edu, David Doll, dadoll@ucanr.edu, or Janet Caprile, jlcaprile@ucanr.edu.

 

The UC Agricultural Issues Center has released a new cost study on walnuts.
Posted on Friday, January 26, 2018 at 10:18 AM
Tags: Walnuts (20)
Focus Area Tags: Economic Development

Almond and Walnut Pest Management Guidelines revised just in time for the holidays

‘Tis the season for baking lots of tasty treats. Breads, cookies, cakes, and candy are just a few that come to mind. What makes many of these treats so tasty is the addition of almonds or walnuts to the list of ingredients.

In California, we are lucky to be at the center of almond and walnut production. According to the California Department of Food and Agriculture's (CDFA's) latest Agricultural Statistics Review, more than 99 percent of the almonds and walnuts produced in the United States are grown in California.

Almond and walnut growers work tirelessly to supply enough nuts to not only satisfy domestic demand, but also for export. Worldwide, almonds rank as the largest specialty crop export. California is the top almond producer in the world, accounting for about 80 percent of all almonds grown. For walnuts, California ranks as the second largest producer in the world. To keep up with this demand, almond and walnut growers must be constantly aware of pests, diseases, and abiotic problems that can affect the tree and growing nuts.

California is the top almond producer in the world, accounting for about 80% of all almonds grown. (Photo: Jack Kelly Clark)

The University of California Statewide Integrated Pest Management Program (UC IPM) has recently published revised Pest Management Guidelines for almonds and walnuts, helping growers prevent and manage pest problems with the most up-to-date information.

Revisions in the Almond Pest Management Guidelines include:

  • A new section on bacterial spot, a new disease of almond in California found in the Sacramento and northern San Joaquin valleys
  • A renamed section on fruit russeting, revised from the old powdery mildew section
  • Significant revisions made to the management section of navel orangeworm, one of the major pests attacking California almonds
  • Improvements on how to do dormant spur sampling section with easier-to-understand information on monitoring and thresholds
Bacterial spot on almond, a new disease of almond in California. (Photo: Brent A. Holtz)

Revisions in the Walnut Pest Management Guidelines include:

  • Updated information on the association between walnut twig beetle and thousand cankers disease
  • New sections for Botryosphaeria and Phomopsis cankers, branch wilt, and paradox canker
  • Significant changes to the walnut husk fly management section
Male (left) and female walnut twig beetles. (Photo: Larry L. Strand)

Both the almond and walnut revised Pest Management Guidelines also include updated information on fungicide efficacy, weed management, and vertebrate management.

Authored by University of California specialists and advisors, the Pest Management Guidelines are UC's official guidelines for monitoring and managing pests in California crops. For more information on pest management in these or other crops, visit the UC IPM website.

Posted on Tuesday, December 19, 2017 at 11:03 AM
Tags: almonds (6), pests (1), walnuts (20)

New cost study for English walnuts released by Agricultural Issues Center

This cost study focuses on establishing a walnut orchard in the Sacramento Valley
A new study on the cost and return of growing English walnuts has been released by UC Agriculture and Natural Resources' Agricultural Issues Center.
 
The study focuses on establishing an orchard and producing walnuts under microsprinkler irrigation in the Sacramento Valley. 

The economic life of the orchard used in this cost analysis is 30 years. The analysis is based upon a hypothetical farm operation of a well-managed orchard, using practices common to the region. Growers, UC ANR Cooperative Extension farm advisors and other agricultural associates provided input and reviews. Assumptions used to identify current costs for the walnut crop, material inputs, cash and non-cash overhead are described. A ranging analysis table shows profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.

The new study is titled 2015 Sample Costs to Establish and Produce English Walnuts in the Sacramento Valley, Microsprinkler Irrigated.”

This study and other sample cost of production studies for many commodities are available. They can be downloaded for free from the UC Davis Department of Agriculture and Resource Economics website at http://coststudies.ucdavis.edu.

For additional information or an explanation of the calculations used in the studies, contact Don Stewart at the UC ANR Agricultural Issues Center at (530) 752-4651 or destewart@ucdavis.edu.

Posted on Monday, November 16, 2015 at 9:10 AM

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