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Posts Tagged: drought
Agave: The new drought-tolerant California crop?
UC Davis to study agave sustainability as tequila, mezcal industry grows
Agriculture in California faces an uncertain future as drought, wildfires and other climate extremes become more commonplace in the West. But a fledgling industry focused on growing and distilling agave plants, which are used to produce tequila and mezcal in Mexico, could be California's answer to fallowed fields and a lack of water.
Earlier this year a group of growers, distillers and retailers formed the California Agave Council to foster collaboration and offer a chance to share knowledge among members who previously had no formal network.
Now, the University of California, Davis, has established the Stuart & Lisa Woolf Fund for Agave Research to focus on outreach and research into the plants and their viability as a low-water crop in the state.
“The rainfall patterns and growing conditions in California are different from those where tequila is made,” said Ron Runnebaum, an assistant professor of viticulture and enology. “It is exciting to begin to harness the capabilities at UC Davis to determine which agave varieties can be grown commercially in California and what flavors can be captured by distillation to make unique California agave spirits.”
The fund was created with a $100,000 seed gift from Stuart and Lisa Woolf, who are Central Valley farmers and have a test plot of about 900 agave plants on 1.5 acres. They hope this gift will encourage others to also contribute.
The gift is focused primarily on optimizing production in California relative to Mexico, where labor costs are lower, and the farmers rely on rain rather than irrigation for water. Stuart Woolf believes California producers could grow larger plants with higher sugar content.
“I really believe we could be very competitive with Mexico,” he said.
The research also offers a chance to better understand the impact of location on the growth of the plant, which can be a source of fiber and alternative sweetener as well as the distilled spirits it can produce.
“As a drought-tolerant plant, agave holds great potential in water-stressed California,” Woolf said. “It's a crop that could get by with little to no water during periods of extreme drought.”
A crop with low water needs
Mezcal can be made from any agave variety in Mexico while tequila, Runnebaum said, comes solely from the blue agave plant grown within the geographically defined region of “Tequila.” In California, blue agave plants can weigh 110 pounds or more, and it takes about 11 pounds of agave to produce one bottle of tequila, according to a UC Davis article published last year. The plants in Mexico weigh 50 to 60 pounds on average, Woolf said.
Agave plants require minimal watering, can serve as firebreaks from wildfires and offer a chance for farmers to plant crops on land that would otherwise have to be fallowed, or abandoned because of a lack of water. It takes roughly six to eight years for the plants to mature.
“If we enter a severe drought, this is a crop I think we can avoid watering totally,” Woolf said. “For me, this plant is kind of coming around at the right time.”
Craig Reynolds, the California Agave Council founding director who has about 500 plants growing, says the industry is in “an embryo stage” and organizing can help the crop expand. He runs California Agave Ventures, which grows blue agave and sells starter plants to other growers.
“It's really taking off,” he said.
Coming together
About 40 growers and distillers gathered for a symposium in May to talk about the crop, from economics and logistics to site planning and processes. It ended with a tasting and sensory analysis of California products.
UC Davis hosted the event to bring people together and introduce them to what the university could offer in terms of research, training and outreach, Runnebaum said.
“I think there's a lot of promise in this potentially being a drought-tolerant crop in California,” he added. “UC Davis can help organize and research.”
The Woolfs would like their gift to be used to answer early research questions about growing sites, plant attributes and possible funding agencies, as well as gathering harvest data and producing a database with that information, according to the gift agreement.
Some key questions to answer: Is frost risk in California too high in relation to Mexico, where the plants thrive? Can California produce a fast-growing, high-sugar, disease-resistant crop?
In addition to creating best agricultural practices for the crop and doing economic analysis, UC Davis could serve as a training ground, much as it does for brewing and winemaking.
“UC Davis also has the potential to train future leaders for this industry,” Stuart Woolf said.
Editor's note: Runnebaum is affiliated with UC Agriculture and Natural Resources through the Agricultural Experiment Station at UC Davis.
Grape experts give workshops on drought preparedness, red blotch
Grape growers and other industry members interested in grape production and water management in vineyards are invited to UC Cooperative Extension's Grapevine Drought Preparedness Workshops.
The workshops will be held in person on Friday, March 4, in San Luis Obispo and Friday, April 1, in Hopland.
Registration is $50 and includes a full day of live instruction from UC Cooperative Extension viticulture and grapevine experts. Lunch will be provided.
For more information and to register, visit https://ucanr.edu/sites/ShortCourse17.
UC Davis Grapevine Red Blotch Disease Symposium
On Wednesday, March 16, UC Cooperative Extension and the UC Davis Department of Viticulture and Enology will host a Grapevine Red Blotch Disease Symposium 9 a.m.-3:30 p.m.
Red blotch disease in grapevines, which can dramatically reduce the value of winegrapes, harms plants by inhibiting photosynthesis in the leaves. Infected vines are unable to conduct water effectively, leaving sugar that is created by photosynthesis stuck in the leaves instead of in the berries.
This event will be presented both in person at the UC Davis Conference Center and livestreamed for those unable to attend in person.
Presentations will cover the role of treehoppers, treatments, mitigation strategies, the impact of the disease on the composition of wine, and more.
Registration is $250 for the in-person symposium at UC Davis and $150 for the livestream. An application for 3.5 CCE units has been submitted to California Department of Pesticide Regulation and is pending approval.
To see the agenda and to register, visit https://wineserver.ucdavis.edu/events/uc-davis-grapevine-red-blotch-disease-symposium.
Researchers pinpoint drought-resistant traits in grape rootstocks
Findings could help wine industry adapt to climate change
Scientists at UC Davis have identified new root traits that help grapevines resist drought. The findings, published in the journal Annals of Botany, could speed up the development of grape rootstocks that protect vines from dry conditions, helping the grape and wine industry adapt to climate change.
The research, led by Department of Viticulture and Enology Assistant Professor Megan Bartlett, comes as 80% of California is experiencing extreme drought.
Most grapevines are not rooted directly into the ground but are instead grafted onto a rootstock, which forms the underground part of the plant and supports growth above ground.
“Rootstocks are an important tool to manage water stress,” Bartlett said. “Our goal was to identify traits that make rootstocks drought tolerant, so that grape breeders can amplify these traits in new varieties.”
Root cell traits
The study focused on traits measuring drought responses in living root cells.
The research specifically identified capacitance – which measures how much roots shrink as they dehydrate – as an important trait for drought tolerance.
“The water that enters the roots has to cross through a band of living cells to reach the xylem – the network of pipes that carries water up to the leaves,” said Bartlett. Most research has focused on xylem traits, but the living cells are often the first to be damaged during drought.
Water stress can shrink, deform, or even kill the living cells, causing the roots to shrivel away from the soil and lose access to the remaining soil water. Vines are then unable to replace water lost to evaporation and are forced to close the stomata – the small pores on the leaves that take in carbon dioxide for photosynthesis – to prevent severe dehydration. But closing the stomata stops photosynthesis and starves the vine of the sugars it needs to grow and ripen fruit.
This study is the first to test whether traits measuring root shrinkage and cell collapse can capture differences in rootstock drought tolerance.
Cell traits and drought tolerance
The researchers grafted Chardonnay onto eight commercial rootstocks. Half of the vines experienced drought conditions and half were kept well-watered in a greenhouse experiment.
The study found the eight rootstocks were surprisingly diverse and varied widely in their traits. The rootstocks also appeared to acclimate to drought by changing their traits in that the droughted vines were less susceptible to shrinkage and cell collapse than the well-watered vines.
Among the traits, capacitance was especially important for drought tolerance. The rootstocks with a lower capacitance (less root shrinkage) were better able to maintain photosynthesis during drought than other rootstocks.
“This research gives us a new trait to target for breeding more drought tolerant rootstocks,” study co-author and Ph.D. student Gabriela Sinclair said.
The research was supported by the American Vineyard Foundation, UC Davis, and by donations to the department from the Rossi family. Researchers at the University of British Columbia and the USDA-ARS Crops Pathology and Genetics Research Unit also contributed to the study.
Coastal grape growers can use less water during drought
Study finds using less doesn't compromise quality
California grape growers in coastal areas can use less water during times of drought and cut irrigation levels without affecting crop yields or quality, according to a new study out of the University of California, Davis.
The findings, published today (Sept. 1) in the journal Frontiers in Plant Science, show that vineyards can use 50% of the irrigation water normally used by grape crops without compromising flavor, color and sugar content.
It sheds new light on how vineyards can mitigate drought effects at a time when California is experiencing a severe water shortage and facing more extreme weather brought on by climate change, according to lead author Kaan Kurtural, professor of viticulture and enology and an extension specialist at UC Davis.
“It is a significant finding,” Kurtural said. “We don't necessarily have to increase the amount of water supplied to grape vines.”
Growers will also be able to use this information to plan for the next growing season. “Everybody's worried about what's going to happen next year,” he said.
Kurtural and others from his lab studied irrigation and cabernet sauvignon grape quality at a research vineyard in Napa Valley over two growing seasons, a rainy one in 2019 and a hyper-arid one in 2020.
They focused on crop evapotranspiration, which was the amount of water lost to the atmosphere from the vineyard system based on canopy size. The weekly tests used irrigation to replace 25%, 50% and 100% of what had been lost by the crop to evapotranspiration.
Researchers found that replacing 50% of the water was the most beneficial in maintaining the grape's flavor profile and yield. The level of symbiotic arbuscular mycorrhizal fungi, which help grapevines overcome stresses such as water deficits, was also not compromised. And the water used to dilute nitrogen application was also reduced, making the process more environmentally friendly.
The water footprint for growing grapes also decreased. For both the 25% and 50% replacement levels, water use efficiency increased between 18.6% and 29.2% in the 2019 growing season and by 29.2% and 42.9% in the following dry year.
While focused on cabernet sauvignon, most red grapes will respond similarly, he said.
“In the end, drought is not coming for wine,” Kurtural said. “There doesn't need to be a tremendous amount of water for grapes. If you over irrigate in times like these, you're just going to ruin quality for little gain.”
Members of Kurtural's lab — Nazareth Torres, Runze Yu, Johann Martinez-Lüscher and Evmorefia Kostaki — are also credited as authors.
University of California Agriculture and Natural Resources provided partial funding.
For more information, contact:
- Kaan Kurtural, Viticulture and Enology, skkurtural@ucdavis.edu
- Amy Quinton, UC Davis News and Media Relations, amquinton@ucdavis.edu
- Emily C. Dooley, College of Agricultural and Environmental Sciences, ecdooley@ucdavis.edu
California food choices won’t save much drought water, researchers find
Can you help fight the California drought by consuming only foods and beverages that require minimal water to produce?
To begin with, not all water drops are equal because not all water uses impact California's drought, the researchers explain.
Drought-relevant water
So just what water does qualify as California drought-relevant water? You can definitely count surface water and groundwater used for agricultural irrigation as well as water used for urban purposes, including industrial, commercial and household uses.
And here are a few examples of what water is not relevant to California's drought:
-- Water used in another state to produce young livestock that are later shipped to California for food production; and
-- Rain that falls on un-irrigated California pastureland. (Studies show that non-irrigated, grazed pastures actually release more water into streams and rivers than do un-grazed pastures, the researchers say.)
In short, California's drought-relevant water includes all irrigation water, but excludes rainfall on non-irrigated California pastures as well as any water that actually came from out-of-state sources and wound up in livestock feeds or young livestock eventually imported by California farmers and ranchers.
Also, the amount of water that soaks back into the ground following crop irrigation doesn't count – and that amount can be quantified for each crop.
Comparing water use for various foods
I think you're getting the picture; this water-for-food analysis is complicated. For this paper, the researchers examined five plant-based and two animal-based food products: almonds, wine, tomatoes, broccoli, lettuce, milk and beef steak.
In teasing out the accurate amount of water that can be attributed to each food, the researchers first calculated how much water must be applied to grow a serving of each crop or animal product. Then they backed off the amount of water that is not California drought-relevant water, arriving at a second figure for the amount of drought-relevant water used for each food.
They provide a terrific graph (Fig. 3) that makes this all quite clear, comparing total applied water with California drought-relevant water used for the seven food products.
Milk and steak top the chart in total water use, with 1 cup of milk requiring 68 total gallons of water and a 3-ounce steak requiring 883.5 total gallons of water.
But when only California drought-relevant water is considered, one cup of milk is shown to be using 22 gallons of water and that 3-oz steak is using just 10.5 gallons of water. (Remember, to accurately assess California drought-water usage, we had to back off rainwater on non-irrigated pastures and water applied out of state to raise young livestock or feed that eventually would be imported by California producers.)
“Remarkably, a serving of steak uses much less water than a serving of almonds, or a glass of milk or wine, and about the same as a serving of broccoli or stewed tomatoes,” write Sumner and Anderson.
Still skeptical? Check out their paper in the January-February issue of the “Update” newsletter of the Giannini Foundation of Agricultural Economics at http://bit.ly/1XKZxxC.
Bon appetit!
