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Drought talk draws ranchers, researchers and climatologists

 

“No matter what sector you’re in, you’re in dire straits,” meteorologist Brad Rippey told the crowd. “California is really ground zero at this point, really sticking out like a sore thumb.”

California's severe drought is entering a fourth year. With that, scientists met with ranchers to give background and gain feedback on a key climate indicator: the U.S. Drought Monitor.

The November 7 workshop held at the University of California, Davis, and webcast to 15 satellite locations across the state posed questions to a panel of experts who help publish the weekly analysis. UC Davis researchers also discussed new findings from in-depth rancher interviews along with strategies for maintaining the nutrition of cattle during the water shortage.

Read the full article at the UC Davis Department of Plant Sciences.

 

With 83 percent of California now in the two highest categories for drought, ranchers are seeing conditions as rare as once in a hundred years.

“We learn a lot when times are tough,” said Rick Roberti, a cattle and hay rancher who attended the workshop. “We're never going to have the water we need. So we might as well learn now how to deal with it.”

In 2012, the second year of California's drought, more than 2,500 of the nation's 3,000 counties qualified for disaster loans, due to designations made through the Drought Monitor.

(Slide: Brad Rippey)

"You see the grass that we had then and the grass that we have now and it's nothing to compare to," says rancher Antonia Suenz of Marysville, California. "The climate is changing."

(Photo: Brad Hooker/UC Davis)

California state climatologist Mike Anderson showed that only 1924 saw less rain than this year, but 2014 has had far higher temperatures: “So not only are you dealing with lack of water, you're dealing with Mother Nature increasing the demand for what water you have.”

Listen to more of this conversation with Anderson at California Drought Watch

Posted on Wednesday, November 26, 2014 at 8:38 AM

Growing wine grapes without irrigation possible for some, not all

It's easier to grow wine grapes without irrigation in the Napa Valley, which receives more rainfall than the San Joaquin Valley.
California's ongoing drought is raising the interest of wine grape growers in dryland farming, reported David Pierson in the LA Times. Pierson interviewed Napa Valley growers who are already dry farming their vineyards. While it may be feasible to rely solely on rainfall in the Napa Valley, San Joaquin Valley growers would have a hard time setting a grape crop without irrigation.

"If you don't water in the San Joaquin Valley, you're not getting a yield," Larry Williams, a professor in the Department of Viticulture and Enology at UC Davis and based at Kearney Agricultural Research and Extension Center, told Pierson.

Last month Sacramento Bee columnist Mike Dunne used Williams' study of water use of chardonnay grapes in the Carneros Region to refute the amount of water a Dutch researcher claimed was required to produce a single glass of wine. “In California vineyards and cellars, is 29 gallons of water to produce a single glass of wine a realistic estimate?” Dunne asked Williams, who explained that California grape yields per gallon of water are much higher than in Europe.

“The mean yield of wine grapes in Europe ... is around 1.8 tons per acre using data I've gleaned from research papers,” Williams says. “The mean chardonnay yields across California are 7.4 tons per acre.”

Based on Williams' research, Dunne wrote, “Vines of the dry-farmed portion yielded 4.9 tons per acre, while vines on the irrigated portion produced 6.3 tons per acre. The upshot was that 14.2 gallons of water was needed in the dry-farmed block to produce a typical 4-ounce pour of wine, while 15.3 gallons of water was needed in the irrigated parcel to produce a 4-ounce pour of wine, totals far lower than the figure calculated by the Water Footprint Network.”

Posted on Tuesday, November 25, 2014 at 4:34 PM

Continued vigilance needed in the fight against Asian citrus psyllid

Asian citrus psyllid is established in some urban Tulare County communities.
Two Asian citrus pysllids (ACP) were found in a trap near Exeter in November, just 10 miles away from the UC Lindcove Research and Extension Center. That brings to 29 the number of locations in the central San Joaquin Valley, from Bakersfield to Dinuba, where Asian citrus psyllids have been trapped.

Perhaps still more unsettling is the fact that reproducing populations of ACP have been found in urban areas in Tulare County, confirming that the pest is established in a county where farmers produce citrus valued at more than $1 billion annually.

“The psyllid is here, it's established, but still at low levels,” said Beth Grafton-Cardwell, director of the Lindcove REC and UC Cooperative Extension citrus entomology specialist. “We need to be very aggressive and treat it and eliminate populations as best we can.”

Asian citrus psyllids are a serious concern for California citrus producers because they spread Huanglongbing (HLB) disease. The disease causes tree decline, production of small, bitter fruit and eventually tree death. There is no cure once a tree is infected.

Around the world, once ACP arrives, HLB soon follows. Such was the case in Florida. ACP was first found in 1998, the disease followed in 2005, and by 2008 it had spread throughout the state.

“They allowed the psyllid and the disease to spread on nursery plants,” Grafton-Cardwell said. “Here, it's a different situation. We are taking many measures to reduce psyllid populations and limit their spread around the state in order to buy researchers time to find long-term solutions for HLB disease."

To date, only one HLB-infected tree has been found in California, a multi-grafted backyard tree in Hacienda Heights. It was quickly removed and destroyed. Other trees may be infected, but not yet detected. It will take a tree with HLB about a year to show visual symptoms of the disease. One goal of UC research is to identify a way to detect HLB more rapidly.

For example, scientists at UC Davis are refining a mobile chemical sensor that can detect diseased citrus trees by sniffing their volatile organic compounds. Another team of scientists is looking for changes in citrus trees' metabolism when infected with HLB.

Citrus growers can help by regularly monitoring their trees for signs of ACP and, when treating for other pests, use insecticides that are known to be effective against ACP. A chart of effective pesticides is on the interactive Asian Citrus Psyllid Distribution and Management website.

The website also contains information for residents who have citrus trees in their landscapes. Photos of the adult and juvenile insects, the distinctive waxy tubules left behind when they feed, and citrus leaves from and HLB-infected tree can aid in determining whether home trees are infested.

An initiative to manage endemic and invasive pests and diseases is part of the UC Division of Agriculture and Natural Resources Strategic Vision 2025.

Posted on Tuesday, November 25, 2014 at 8:12 AM

What’s the difference between yams and sweetpotatoes?

Do you know the difference between a yam and a sweetpotato?

“A true yam is not grown in the U.S., it's found in South America,” says Jason Tucker, vice president of the California Sweetpotato Council. Real yams have dry, dark flesh and are not the same plant species as sweetpotatoes, he explained.

“A yam is a sweetpotato, at least for those grown in the U.S.”, says Scott Stoddard, UC Cooperative Extension advisor in Merced County. “The rest of country has predominately just one type of sweetpotato, with tan skin and orange flesh, but in California, we have four marketing classes.”

The four kinds of California sweetpotatoes are

  • Jewell, with tan skin and orange flesh
  • Jersey, with light yellow skin and white flesh
  • Oriental, with purple skin and white flesh
  • Garnet, with red skin and deep orange flesh

The red-skinned sweetpotatoes are what many people in the United States call yams.

The California Sweetpotato Council spells sweetpotato as one word because it isn't a potato, it is a different plant species.

Sweetpotato classes, from left, are Jewell, Oriental, Jersey and Garnet. Photo courtesy of the California Sweetpotato Council.
Posted on Friday, November 21, 2014 at 8:26 AM

The food vs. fuel debate: Growing biofuel in the U.S.

Studies suggest biofuel can be grown on 'marginal land,' but no standard definition of 'marginal land' exists.
In order to slow global climate change and achieve greater energy independence, Americans are showing an increasing interest in switching over to clean, renewable fuels made from home-grown crops. In fact, Congress has mandated that at least 16 billion gallons of cellulosic ethanol be added to the U.S. fuel supply by 2022.

However, estimates suggest that growing crops to produce that much biofuel would require 40 to 50 million acres of land, an area roughly equivalent in size to the entire state of Nebraska.

“If we convert cropland that now produces food into fuel production, what will that do to our food supply?” asks Maggi Kelly, UC Cooperative Extension specialist and the director of the UC Division of Agriculture and Natural Resources Statewide IGIS Program. “If we begin growing fuel crops on land that isn't currently in agriculture, will that come at the expense of wildlife habitat and open space, clean water and scenic views?”

Kelly and UC Berkeley graduate student Sarah Lewis are conducting research to better understand land-use options for growing biofuel feed stock. They used a literature search, in which the results of multiple projects conducted around the world are reviewed, aggregated and compared. 

“When food vs. fuel land questions are raised in the literature, authors often suggest fuel crops be planted on ‘marginal land,'” Kelly said. “But what does that actually mean? Delving into the literature, we found there was no standard definition of ‘marginal land.'”

Kelly and Lewis' literature review focused on projects that used geospatial technology to explicitly map marginal, abandoned or degraded lands specifically for the purpose of planting bioenergy crops. They narrowed their search to 21 papers from 2008 to 2013, and among them they found no common working definition of marginal land.

“We have to be careful when we talk about what is marginal. We have to be explicit about our definitions, mapping and modeling,” Kelly said. “In our lab, we are trying to understand the landscape under multiple lenses and prioritize different uses and determine how management regimes impact the land.”

The research report, titled Mapping the Potential for Biofuel Production on Marginal Lands: Differences in Definitions, Data and Models across Scales, was published in the International Journal for Geo-Information.

Click here for this story in Spanish.

An initiative to improve energy security and green technologies is part of the UC Division of Agriculture and Naturalist Resources Strategic Vision 2025.

 

Posted on Friday, November 21, 2014 at 7:45 AM

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