Posts Tagged: UC Davis College of Agricultural and Environmental Sciences
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.”
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.”
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.
“When first-generation ranchers succeed, we all succeed,” says Kate Munden-Dixon, a Ph.D. student working with Leslie Roche, Cooperative Extension rangeland specialist with the UC Division of Agriculture and Natural Resources and the UC Davis Department of Plant Sciences.
Munden-Dixon and Roche recently discovered that many new livestock managers aren't plugged into information networks such as UC Cooperative Extension and rancher coalitions that provide science and strategies for making sustainable rangeland management decisions. This lack of connection can make first-generation ranchers more vulnerable when dealing with challenges like drought and climate variability, according to their study, which was recently published in Rangeland Journal.
To help bridge the gap, Munden-Dixon landed a $25,000 Graduate Student Grant from Western Sustainable Agriculture Research and Education, a USDA program, to reach out to new ranchers and rangeland managers.
Why rangelands matter
More than one half of California — 38 million acres — is rangeland that provides open space, healthy watersheds, carbon storage, food, fiber and habitat for diverse plants and wildlife. UC Davis research indicates grasslands and rangeland have become more resilient at sequestering or consuming carbon dioxide pollution than forests in California, making them especially important in a warming world.
But rangeland and livestock production are at risk because more rangeland is being converted to housing and crop production. The average age of ranchers in California is 62, and fewer children are taking over the family ranch.
Enter a new wave of rangeland managers. Many of these young ranchers don't yet have access to the capital required to purchase land and large head of cattle and other livestock. Instead, they often contract with public and private landowners to graze goats, sheep and cattle to restore landscapes and reduce fire vegetation.
“What we really need is support in connecting land and contract opportunities,” says Brittany Cole Bush, an “urban shepherdess” and former contract sheep and goat grazer. She now consults with land owners and public agencies from her home base in Southern California. “We need market research that shows the value that grazing brings to fire abatement, soil conservation and so much more. Market research would increase our value and help us become viable players.”
Munden-Dixon is interviewing 40 new rangeland managers from across California to explore how decision-making by different demographics influences adaptation to climate change and quality of life. Munden-Dixon and her team are also hosting workshops to make sure Cooperative Extension specialists understand and can respond to all ranchers' needs.
“There is both a need and opportunity for a new generation of livestock managers that is able to adapt to California's changing climate,” Munden-Dixon says. “This next generation may not look like your typical rancher, so we want to ensure organizations are helping all ranchers succeed, regardless of their demographics or land tenure.”
The power of connection
Munden-Dixon would like to become a Cooperative Extension specialist herself one day. Working with first-generation ranchers reminds her that collaboration and public engagement are critical to addressing issues in sustainable agriculture.
“There is no one answer or single expert when it comes to building healthy food systems,” Munden-Dixon says. “We find solutions when we work together.”
UC Agriculture and Natural Resources (UC ANR) provided seed money to launch a new Pastured Poultry Farm at UC Davis. The farm is home to 150 young chickens and a living laboratory where students and faculty researchers hope to develop innovative solutions benefiting pasture-based farms, integrative crop-and-poultry farms and backyard flocks.
Pasture-based chicken production offers many benefits as well as some challenges in terms of food safety, animal health and welfare, and environmental impacts, said Maurice Pitesky, UC ANR Cooperative Extension poultry specialist with the School of Veterinary Medicine and co-leader of the poultry project.
The new 4.5-acre farm, located about one mile west of the central UC Davis campus, includes a seeded, irrigated pasture, where the chickens can forage. In the center is a bright red student-built Eggmobile for night time housing. The ‘coop on wheels' can be strategically moved around the land for consistent fertilization. The pasture uses a portable electronic fence to protect against predators and is surrounded by a 50-foot band of uncultivated land to serve as a wildlife buffer.
“This is a unique innovation, research and outreach resource for the Western United States,” Pitesky said. “The project includes faculty and students with expertise in veterinary medicine, husbandry, welfare, pasture management and engineering, which allows us to address issues related to predator control, welfare, food safety and food efficiency.”
Debbie Niemeier, professor in the Department of Civil and Environmental Engineering, and her team have already developed a number of innovations for the project, including a tarp-pulley system, portable-shade and predator-mitigation structures, an automatic watering system, and modular roll-out nest boxes.
One of the advantages of the pasture-based system is the opportunity for a farmer to integrate chicken production with a farm's existing cropping system, with the chickens providing natural fertilizer for the crops.
“It's also a way for crop farmers to move into poultry production without expanding their land or adding nitrogen fertilizer to their farming system,” Pitesky said.
Eggs produced by the project's flock will initially be donated to food shelters. The potential for eventual egg sales to the community is being explored. Eventually, the research team hopes to construct multiple Eggmobiles with different designs, and in time would like to expand the project to include broiler chickens, as well as cropping systems that integrate poultry, in order to fully maximize the potential of the land for food production.
A list of donors and other information about the UC Davis Pastured Poultry Farm can be found online. The School of Veterinary Medicine has established an online site where individuals interesting in supporting the UC Davis Pastured Poultry Farm financially can make donations.
Author: Patricia Bailey
Ten large, shiny tanks stand near the Robert Mondavi Institute for Wine and Food Science at UC Davis, holding more than a year of rainwater and the key to processing food and drink during a drought. The water tanks, and the teaching-and-research winery they support, are showing students and winemakers throughout the world how to reduce processing costs, improve wine quality, and protect the planet's dwindling natural resources.
Roger Boulton, UC Davis professor of enology and chemical engineering. “We're demonstrating how you can operate a winery, brewery, or any food processing plant with the water that falls and the sun that shines on your roof.”
The work is the latest in more than a century of trail-blazing viticulture and enology science at UC Davis. UC Davis researchers are working with Cooperative Extension specialists and farm advisors with UC Agriculture and Natural Resources to help winemakers and grape growers sustainably produce premium wine.
Water is critical to winemakers in drought-stricken California and beyond. Grapes aren't a very thirsty crop to grow, but keeping fermentors clean is another story.
A typical winery uses four to six gallons of water after the grapes are harvested to produce one gallon of wine, and most of that water is used to wash equipment. Boulton and David Block, chair of the UC Davis Department of Viticulture and Enology, are developing self-cleaning fermentors capable of recycling 90 percent of that water. The goal: affordable technology and alternative practices that use less than one gallon of water to produce one gallon of wine.
Winemakers currently remove sticky, fermented, grape residue from tanks with water and elbow grease. Clean-in-place technology replaces hand-cleaning with an automated system that sprays tanks with diluted solutions of potassium hydroxide and potassium bisulfate.
“The dairy industry has used clean-in-place technology since the 1960s and the pharmaceutical industry since the 1990s,” says Block, a chemical engineer and enologist who helped the pharmaceutical industry manage clean-in-place technology before coming to UC Davis in 2008. “It's a little different with dairy and pharmaceuticals, where poor sanitation can kill you, but the concept is similar.”
“We will filter and reuse that water at least five times, hopefully one day up to 10 times,” Boulton says. “It's not waste water. It has no phosphates, no nitrates, and no chlorine. Clean-in-place technology represents a huge potential for water and labor savings.”
Industry is starting to notice.
“Clean-in-place technology is very attractive to us,” says Ashley Heisey, director of winemaking at Long Meadow Ranch in Rutherford and a UC Davis viticulture and enology graduate. “Water is such a critical issue. Long Meadow Ranch owners Ted, Chris, and Laddie Hall built our facilities with great concern for the environment, and thanks to UC Davis, we can take it one step further.”
In Sacramento, grocer Darrell Corti from Corti Brothers Market says where UC Davis leads, winemakers will eventually follow.
“What we know about grape-growing and winemaking is primarily due to the work they do at UC Davis,” Corti says.
A longer version of this story is in the magazine Edible Sacramento.
There's a "me" in mead. There also could be a "u" in mead, as in "you." There's definitely a honey bee, as without the bee and the honey, there's no mead. The UC Davis Honey and Pollination Center, headed by executive director Amina Harris and headquartered at the Robert Mondavi Institute for...
Mead! It all begins with the honey bee. (Photo by Kathy Keatley Garvey)
Amina Harris, executive director of the UC Davis Honey and Pollination Center, displayed honey and note cards at the UC Davis College of Agricultural and Environmental Sciences' 25th annual College Celebration. The photos on the note cards were donated by Kathy Keatley Garvey.