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Climate change is impacting California tree crop farms

Rising temperatures appear to be reducing the number of hours tree crops in the San Joaquin Valley are subjected to chill during the winter, a critical factor in producing a profitable yield, reported Ezra David Romero on Valley Public Radio, KVPR-FM.

Pistachios, for example, require temperatures between 32 and 45 degrees for about 700 hours each winter, but for the past four years have had less than 500 chill hours.

UC Davis researcher Hyunok Lee recently published a study about climate change impacts on agriculture in UC Agriculture and Natural Resources' peer-reviewed journal California Agriculture. The study found that winter temperatures are increasing more than any other time of year. Her modeling looks at the year 2050 in Yolo County.

“Our agriculture will continue,” Lee said. “But if you look at . . . like 20 years or 30 years. The pattern may change a little bit, crops may move a little bit north.”

Insufficient chill hours can delay the opening of leaf and flower buds in crops such as walnuts, which may result in a smaller yield. (Photo: Will Suckow))

 

Romero spoke to UC Cooperative Extension farm advisor Craig Kallsen, who holds the UC Cooperative Extension Presidential Chair for Tree Nut Genetics. Kallsen is conducting trials aimed at finding pistachio varieties with novel nut, tree growth and yield characteristics, and varieties that produce a high yield even under low-chill conditions.

"We're trying to use the other species of pistachios actually to see if we can come up with something that has a low chill requirement. It's pretty hypothetical at this stage,” Kallsen told Romero. “We made quite a few crosses this spring and we actually hope to put a trial in a low chill area.”

David Doll, UC Cooperative Extension farm advisor in Merced County, is studying other tactics to improve winter chill, such as using overhead sprinklers to cool the trees and painting them white with liquid clay to reflect sunlight.

"So this is something that could impact a lot of farmers over the next 10, 20, 30 to 40 years,” Doll said. “And in fact it's already impacting farmers on random given years across the state."

 

Posted on Wednesday, January 18, 2017 at 9:04 AM

California governor sets aside funds to promote soil health

California Gov. Jerry Brown has included $7.5 million in the 2017-18 budget to launch the Healthy Soils Initiative, reported Bob Gore in a commentary on Techwire.net.

The story said CDFA secretary Karen Ross announced the development at a recent meeting, saying "We're starting from the ground up."

Carlos Suarez of the U.S. Natural Resources Conservation Service was also quoted in Gore's story. Suarez said the funding puts "soils back into the forefront of agriculture. Feeding the people is the real issue. We have to take care of our soils."

Jenny Lester Moffitt, CDFA deputy secretary and walnut farmer, is the point person for the Governor's Healthy Soils Initiative, which formally starts Jan. 19. Moffitt said the $7.5 million will fund research and demonstration projects so the "UC Ag and Natural Resources engine will rev up."

California's Healthy Soils Action Plan notes that the new initiative will "provide boots-on-the-ground" research, education and technical support to the agricultural industry.

"Utilizing partners such as Natural Resource Conservation Services, University of California Cooperative Extension and Resource Conservation Districts, (the initiative will) enhance and expand technical assistance and outreach activities to distribute new and existing management practice information to farmers and ranchers," the action plan says on Page 5.

Boots on the ground where a former almond orchard stood. The shredded trees will be incorporated into the soil to build soil organic matter.
Posted on Friday, January 13, 2017 at 2:15 PM

Collaboration is the key to collective decision-making

When people don't think about the impact of their decision-making on others, it can ultimately lead to tragedy - the tragedy of the commons, said UC Agriculture and Natural Resources researcher Mark Lubell during an interview on Jefferson Public Radio. Lubell, director of the Center for Environmental Policy and Behavior at UC Davis, studies human decision-making in the context of the environment.

"People think about what happens on their private land and make their private decisions, but they don't think about how their private decisions affect others," Lubell said. "You see this all the time with human decision-making."

An example he uses with his students is how they and their roommates manage their shared kitchens.

"When one person's dishes pile up, it impacts the others," Lubell said. "I ask how they would make rules to solve the problem."

Lubell said the parties need to collectively develop a policy that is mutually beneficial.

"If we didn't have that capacity, we would be in big trouble," Lubell said.

Cooperation tends to be the norm, however the media is more likely to cover cases of conflict, so they tend to get more attention.

UC researcher Mark Lubell uses dirty dishes in a shared kitchen as an example of how one person's decisions impacts others.
Posted on Thursday, January 12, 2017 at 11:10 AM

San Joaquin Valley farmers may one day produce avocados

Despite hot summers and cold winters, UC Cooperative Extension specialist Mary Lu Arpaia believes the San Joaquin Valley could be home to expanded California avocado production, reported Gregory Barber on Wired.com

Currently, most of the state's avocados are grown in the mild coastal areas of San Diego and Ventura counties, where consumer-favorite Hass avocados flourish. But high land value and low water quality are limitations on the industry. The vast and fertile San Joaquin Valley beckons, but summer temperatures that frequently top 100 degrees and occasional winter freezes aren't ideal for Hass.

Arpaia has planted a variety of avocado cultivars at the UC Lindcove Research and Extension Center in eastern Tulare County to determine which trees produce creamy, nutty avocados, and maintain other desirable traits - such as high yield and small tree size - while subjected to the valley's climate extremes.

The California Avocado Commission funded the orchard's establishment.

"The industry wasn't really too keen about me putting a site here (at Lindcove)," Arpaia said. "But I'm stubborn and that's why it's here."

Each year three new avocado varieties are planted in the orchard. Though the breeding process is slow, Arpaia dreams that one day avocados will be sold in supermarkets much like the wide variety of apples.

"We're probably 20 years behind the apple industry at this point," Arpaia said. "Do we have anything out here that's going to achieve that dream?"

Finding an avocado variety ideal for valley temperatures has other benefits. It would give citrus farmers another option should their industry be threatened by Huanglongbing (HLB) disease. Already, the pest that spreads HLB, Asian citrus psyllid, is established in some parts of the valley and spreading. Once a tree is infected with HLB, it cannot be cured.

“Growers have made good money on avocados,” Arpaia said. “In the San Joaquin Valley, water is relatively cheap and we have better water quality than San Diego County. There are good, well-drained soils. Avocados' frost sensitivity is similar to lemons. If farmers have property where they can grow lemons, they could try avocados.”

 

Avocados planted in a research plot at the UC Lindcove Research and Extension Center.
Posted on Friday, January 6, 2017 at 11:43 AM

Feral cats are a threat to wildlife

Feral cats are thought to be responsible for the extinction of no less than 20 native Australian mammal species, reported Weston Williams in the Australia edition of the Christian Science Monitor. The population density is smaller than the density in North America and Europe, but their impact on the wildlife Down Under is of grave concern.

Australia is not alone. A 2013 study found that cats kill as many as 3.7 billion birds and 20.7 billion small mammals in the U.S. every year.

"All outdoor cats can pose risks to wildlife," said Niamh Quinn, UC Cooperative Extension human-wildlife interactions advisor based at the UC South Coast Research and Extension Center in Irvine. "Keeping cats indoors limits their risk to native species."

According to the story, many conservationists consider cats to be an invasive species and "tough measures" are required protect native animals from their carnivorous habits.

"Currently, trap-neuter-return (TNR) programs are not effective at curbing the population," Quinn said. "Mathematical models of feral cat populations indicate that 71 to 94 percent of a population must be neutered for the populations to decline, assuming there is no immigration . . . Current TNR programs are not operating at this rate."

In Australia, the federal government plans to cull 2 million cats over five years.

All outdoor cats can pose risks to wildlife. Above a herd of feral cats gather in a vacant lot. (Photo: Wikimedia Commons)
Posted on Thursday, January 5, 2017 at 2:22 PM

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