Posts Tagged: UC Davis
Research shows land managers should clean nest boxes in autumn to avoid disturbing the raptors
When it comes to American barn owls, forget spring cleaning.
The best time of year to clean out nest boxes to ready them for breeding pairs is the fall months of September through November, according to research out of the University of California, Davis, that analyzed nearly a century of banding and other records.
In a paper published in the Journal of Wildlife Management, researchers found that the median egg laying date for barn owls (Tyto furcata) in California is Feb. 20, so cleaning nest boxes in the fall is recommended.
“The risk is you could disrupt a nest that has already started,” said lead author Ryan Bourbour, a Ph.D. candidate in ecology in the Department of Animal Science at the time of the study. “We want to reduce disturbances to nesting pairs even in the weeks prior to egg laying.”
American barn owls offer a natural way for land managers and agricultural operations to control pests, because the raptors eat mice, gophers and rats. One breeding pair can consume up to 2,000 rodents annually, according to the UC Davis School of Veterinary Medicine.
But natural tree cavities and old barn structures are not as plentiful as they once were, so installing nest boxes can attract the barn owls. And land managers who spend money installing these “nest box networks” have long asked about the best time of year to do maintenance and cleaning. Planning cleaning and maintenance well before the start of the breeding season is “part of making that nest box worthwhile,” Bourbour said.
Pellets add up
After eggs hatch, nestlings spend their early days eating and living in the nest boxes until they are able to leave the nest, said Breanna Martinico, another paper author and an animal science Ph.D. candidate in ecology.
The nestling period of roughly 65 days is considered long.
“That's two months where owls are living and growing exclusively in that nest box,” said Martinico, who is also a UC Cooperative Extension human-wildlife interactions advisor in Napa, Lake and Solano counties.
As many as five or six nestlings are typically in a box, and they eat up to four or five rodents each day. Nestlings swallow their prey whole, and what isn't digested — fur and bones — is coughed up in round or oval-like pellets.
“They're in there for seven to eight weeks just regurgitating these pellets,” Bourbour said. “A lot of pellets pile up over the course of a breeding season and a lot of these boxes need to be cleaned out.”
From anecdotal to data
Discussions about how early the breeding season starts have mostly been anecdotal. To get a better picture, the paper's authors analyzed 96 years of banding records from the United States Geological Survey Bird Banding Lab and 39 years of intake records from California Raptor Center at UC Davis. Both databases helped them estimate the typical egg laying time of year in California, Martinico said.
Having this information can help land managers ensure maintenance is done and nest boxes are safe for the next breeding pair, helping barn owl populations while also benefiting agricultural operations.
“We can give them tools to manage barn owl nest box networks effectively and maximize pest control through owls,” Martinico said.
Additional co-authors include Emily Phillips, Jessica Schlarbaum and Joshua Hull in the Department of Animal Science, Michelle Hawkins in the Department of Medicine and Epidemiology at the UC Davis School of Veterinary Medicine and Sara Kross from Columbia University.
Funding came from the National Institute of Food and Agriculture's Western Sustainable Agriculture Research and Education program.
The journal article is entitled Banding records of nestling barn owls reveal optimal timing for nest box maintenance in California./h3>/h3>/h3>
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.
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./h3>/h3>/h3>
Discovery could reduce nitrogen pollution, save farmers billions
Researchers at the University of California, Davis, have found a way to reduce the amount of nitrogen fertilizers needed to grow cereal crops. The discovery could save farmers in the United States billions of dollars annually in fertilizer costs while also benefiting the environment.
The research comes out of the lab of Eduardo Blumwald, a distinguished professor of plant sciences, who has found a new pathway for cereals to capture the nitrogen they need to grow.
The discovery could also help the environment by reducing nitrogen pollution, which can lead to contaminated water resources, increased greenhouse gas emissions and human health issues. The study was published in the journal Plant Biotechnology.
Nitrogen is key to plant growth, and agricultural operations depend on chemical fertilizers to increase productivity. But much of what is applied is lost, leaching into soils and groundwater. Blumwald's research could create a sustainable alternative.
“Nitrogen fertilizers are very, very expensive,” Blumwald said. “Anything you can do to eliminate that cost is important. The problem is money on one side, but there are also the harmful effects of nitrogen on the environment.”
A new pathway to natural fertilizer
Blumwald's research centers on increasing the conversion of nitrogen gas in the air into ammonium by soil bacteria — a process known as nitrogen fixation.
Legumes such as peanuts and soybeans have root nodules that can use nitrogen-fixing bacteria to provide ammonium to the plants. Cereal plants like rice and wheat don't have that capability and must rely on taking in inorganic nitrogen, such as ammonia and nitrate, from fertilizers in the soil.
“If a plant can produce chemicals that make soil bacteria fix atmospheric nitrogen gas, we could modify the plants to produce more of these chemicals,” Blumwald said. “These chemicals will induce soil bacterial nitrogen fixation and the plants will use the ammonium formed, reducing the amount of fertilizer used.”
Blumwald's team used chemical screening and genomics to identify compounds in rice plants that enhanced the nitrogen-fixing activity of the bacteria.
Then they identified the pathways generating the chemicals and used gene editing technology to increase the production of compounds that stimulated the formation of biofilms. Those biofilms contain bacteria that enhanced nitrogen conversion. As a result, nitrogen-fixing activity of the bacteria increased, as did the amount of ammonium in the soil for the plants.
“Plants are incredible chemical factories,” he said. “What this could do is provide a sustainable alternative agricultural practice that reduces the use of excessive nitrogen fertilizers.”
The pathway could also be used by other plants. A patent application on the technique has been filed by the University of California and is pending.
Dawei Yan, Hiromi Tajima, Howard-Yana Shapiro, Reedmond Fong and Javier Ottaviani from UC Davis contributed to the research paper, as did Lauren Cline from Bayer Crop Science. Ottaviani is also a research associate at Mars Edge.
The research was funded by the Will W. Lester Endowment. Bayer Crop Science is supporting further research on the topic.
Editor's note: Blumwald is affiliated with UC Agriculture and Natural Resources through the Agricultural Experiment Station at UC Davis./h3>/h3>
Project designed to prevent red blotch and other grapevine diseases
A new, $5.25 million greenhouse is being built on the University of California, Davis, campus to safeguard an important grapevine collection from red blotch disease and other pathogens.
The 14,400-square-foot greenhouse will have a vestibuled entry, be insect-proof and provide another level of disease protection. It is being spearheaded by Foundation Plant Services, or FPS, which provides the U.S. grape industry with high-quality, virus-tested grapevine plant material.
The program serves as the primary source for grapevine plant material distributed to nurseries under the California Department of Agriculture's Grapevine Registration and Certification Program, which provides the majority of grapevines planted in the United States. For the grape industry, it is essential to protect this material from disease-carrying insects and guarantee fast access to clean plant material.
“The program is considered the largest quarantine center for the grapevine industry in the United States,” said Maher Al Rwahnih, a plant pathologist and FPS director. “This is kind of a game changer for us.”
A history of serving the grapevine industry
FPS has maintained healthy grapevine planting stock on the UC Davis campus for more than 70 years in open fields at the Classic and Russell Ranch foundation vineyards. FPS scientists first detected grapevine red blotch virus at Russell Ranch in 2017. By 2021, an estimated 51.6% of the crop there was infected. Material from that vineyard is not being sold, and the site is now part of an epidemiological study to try to pinpoint how the disease is transmitted.
FPS pathologists have detected red blotch on less than 1% of the Classic vineyard crop. But it may not always be that way in the future.
“We don't know how long the Classic vineyard will remain clean,” Al Rwahnih said. “Every testing season, this is what keeps me up at night. We're not sure why it's happening in Russell Ranch and not the Classic vineyard.”
Once the greenhouse is operating, grapevines propagated from plant material from the Classic vineyard will be moved into the greenhouse, tested and verified as clean from disease. From there it will be sold to nurseries, which will grow additional plants to sell to growers.
Two greenhouses part of plan
Normally the foundation has 4,000 vines available, but the greenhouse will only house 2,000 vines, so inventory will be cut in half.
“This phase is just a starting phase,” Al Rwahnih said. “It's not sufficient for our needs.”
FPS plans to build another greenhouse in the next two to three years to increase capacity.
Industry groups and FPS identified greenhouses as the best way to protect the plants from red blotch and other pathogens transmitted by insects. They are also consulting with those same people on the grape varieties to include in the greenhouse.
“We have a large selection, and we need to make sure all the varieties that are important to industry are contained,” he said.
The first greenhouse is expected to be finished by the end of 2023.
Funding for the first greenhouse is coming from a variety of sources. The California Fruit Tree, Nut Tree and Grapevine Improvement Advisory Board, managed by the California Department of Food and Agriculture, contributed $4 million to the project. The California Grape Rootstock Research Foundation gave $500,000, Foundation Plant Services with UC Davis is funding $450,000, and the California Grape Rootstock Commission gave $100,000.
“This is crucial for the grapevine industry, and we are very grateful for the support,” Al Rwahnih said./h3>/h3>/h3>
Scientists make the first large-scale estimate of live microorganisms consumed in the U.S. diet
Our diets provide us with the building blocks we need to stay healthy and fight disease. The nutrients in foods and beverages can be tallied up to know if we are getting what our bodies need. Yet what if a nutrient has been overlooked? For instance, friendly microbes in raw and fermented foods have not been measured as part of our diets — until now.
“Ultimately we want to understand if there should be a recommended daily intake of these microbes to keep us healthy, either through the foods or from probiotic supplements,” said Maria Marco, a professor in the food science and technology department at UC Davis. “In order to do that, we need to first quantify the number of live microorganisms we consume today in our diets.”
Marco co-authored a new study with a group of scientists that examined the number of living microbes per gram of more than 9,000 different foods consumed by nearly 75,000 adults and children. It found that around 20% of children and 26% of adults consumed foods with high levels of live microorganisms in their diet. Both children and adults increased their consumption of these foods over the 18-year study period. The study, published in the Journal of Nutrition, is the first large-scale estimate of how many live microbes are consumed by Americans every day.
“This trend is going in the right direction. Exposure to friendly microorganisms in our foods can be good for promoting a healthy immune system.” said Marco.
Foods for gut health
Study authors examined the National Health and Nutrition Examination Survey to create the estimate. The health and dietary database contains extensive information on the foods consumed by Americans daily. Food science and fermentation experts assigned each food an estimated range of live microbes per gram, creating categories of foods with low, medium and high levels of live microbes. Foods in the high category included fermented dairy foods such as yogurt, fermented pickles and kimchi. Fresh, uncooked fruits and vegetables were also good sources of live microorganisms, represented in the medium category.
The analysis was funded by a grant from the International Scientific Association for Probiotics and Prebiotics, or ISAPP. The microorganisms quantified in this study are not necessarily probiotics.
“By definition, a probiotic must be well-defined and have a demonstrated health benefit at a quantified dose. Live microbes associated with food as a category, however, do not generally meet the criteria of a probiotic,” said corresponding author Mary Ellen Sanders, executive science officer for the ISAPP.
The publication is part of a larger global effort to determine how live dietary microbes might contribute to health.
“There is no doubt that the microbes we eat affect our health. When we think of microbes in our food, we often think of either foodborne pathogens that cause disease or probiotics that provide a documented health benefit,” said co-author Colin Hill, a professor of microbial food safety with University College Cork, Ireland. “But it's important to also explore dietary microbes that we consume in fermented and uncooked foods. It is very timely to estimate the daily intake of microbes by individuals in modern society as a first step towards a scientific evaluation of the importance of dietary microbes in human health and well-being.”
Other scientists co-authoring the paper were ISAPP board members Robert Hutkins, Dan Merenstein, Daniel J. Tancredi, Christopher J. Cifelli, Jaime Gahche, Joanne L. Slavin and Victor L. Fulgoni III.
Editor's note: Maria Marco is affiliated with UC Agriculture and Natural Resources as an Agricultural Experiment Station faculty member./h3>/h3>