Posts Tagged: UC
Understanding cattle grazing personalities may foster sustainable rangelands
Matching herds to landscape can support animal growth and ecological needs
Not all cattle are the same when it comes to grazing. Some like to wander while others prefer to stay close to water and rest areas.
Recognizing those personality differences could help ranchers select herds that best meet grazing needs on rangelands, leading to better animal health and environmental conditions, according to a new paper from the University of California, Davis, published in the journal Applied Animal Behaviour Science.
“Cattle can actually be beneficial for the rangelands,” said lead author Maggie Creamer, who recently earned her Ph.D. in animal behavior at UC Davis. “Vegetation in rangelands actually need these kinds of disturbances like grazing.”
Ranchers can add elements to the rangeland such as water, mineral supplements and fencing to influence where cattle graze, but little research has been done on how those efforts affect individual cows. Considering personalities could save money.
“If you're spending all this money to add a management tool in order to change the distribution of your animals, that's a huge cost to ranchers,” said Creamer. “Thinking about other tools, or selecting certain animals with these grazing traits, might be a better way to optimize the distribution on rangeland rather than spending a bunch of money for something that may ultimately not pan out for all your animals.”
Effects of grazing
Livestock graze on an estimated 56 million acres in California, and healthy rangelands host native vegetation and animals, foster nutrient cycling and support carbon sequestration.
Uneven grazing can degrade water quality, soil health and habitats. Optimizing grazing — including the even spread of cow pies — can improve the ecosystem while also reducing fuel loads for wildfires.
To better understand individual grazing patterns, researchers went to the UC Sierra Foothill Research and Extension Center in Browns Valley and tracked 50 pregnant Angus and Hereford beef cows fitted with GPS collars.
The research
The cattle, which were tracked from June to August over two years, had access to 625 acres of grasslands and treed areas ranging in elevation from 600 to 2,028 feet. In the second year, a new watering site was added at a higher elevation.
Across the two years, the cows showed consistent and distinct grazing patterns even when water sources changed. Age and stage of pregnancy did not affect patterns, though cattle tended to clump near water and rest sites on hotter days.
The cows that ventured into higher elevations and farther from watering sites had more variability in their grazing patterns than those that stayed at lower elevations near water. That suggests it may be harder for non-wanderers to adjust to some landscapes.
“Thinking about the topography of your rangeland and your herd of cows can benefit both the animals and the sustainability of the land,” said Creamer, who next month begins work as a postdoctoral scholar in North Carolina.
Gauging personalities
Keying in on personality type may sound difficult, but the researchers also found some clues as to how to pinpoint the wanderers and homebodies. Unlike cattle at feedlots, the breeding cow population, especially on rangelands in California and other western states, live largely “wild” lives and are rarely handled, save for vaccinations and weaning.
Research due to be published later this year found that paying attention to individual cow reactions during those events can help determine personalities. The cows that appeared more passive during those handling interactions tended to be nomadic.
“We found that you can maybe predict those hill climbers if you kind of look at how they act when the veterinarian or rancher handle them,” said senior author Kristina Horback, an associate professor in the Department of Animal Science at UC Davis.
Informing practices
For ranchers, the findings could be invaluable, said Dan Macon, a livestock and natural resources Cooperative Extension advisor in Placer and Nevada counties for UC Agriculture and Natural Resources.
“Any time we can improve our understanding of cattle behavior, particularly at the individual level, it can improve how we handle livestock and manage the landscape,” he said.
Macon said that during the recent drought, it was hard to get cattle into higher country, but if ranchers could have selected the nomads, it may have saved money in terms of ranch labor and other efforts.
“If you ask a rancher who has been attentive to their cattle over many years, they know the personalities,” Macon said.
For Creamer and Horback, the research opens new doors into understanding herd behavior and dynamics, one that could be a cheaper alternative to high-tech solutions.
“Animal science tends to look overlook the mind of the animal when searching for solutions to challenges,” Horback said. “It's always been a direct line to genetics for immunity or nutrition, but nothing about the mind of the animal. And that's such a loss. There's so much we can learn from behavior in the end.”
The Russell L. Rustici Rangeland and Cattle Research Endowment supported the research.
This article was first published on the UC Davis News site.
/h3>/h3>/h3>/h3>/h3>Organic strawberry yields boosted by technique refined through UCCE research
Anaerobic soil disinfestation helps suppress weeds, disease without fumigants
Troubled by puny plants, low yields and persistent mite problems, third-generation Southern California strawberry grower Glen Hasegawa was ready to give up on his transition from conventional to organic 12 years ago.
“I've always liked a challenge – but it turned out to be more of a challenge than I thought it would be!” he said.
But then, with the help of scientists including Oleg Daugovish, UC Cooperative Extension strawberry and vegetable crop advisor in Ventura County, Hasegawa tried a technique called anaerobic soil disinfestation (ASD). When applied correctly, the multi-step ASD process creates a soil environment that suppresses pathogens and weeds and makes for healthier, more robust crop growth.
“Back in the day, it was really hard to get the plant growing vigorously in organic,” said Hasegawa, owner of Faria Farms in Oxnard. “So we started using the ASD and then you could definitely see that the plant had more vigor and you could grow a bigger, better plant using it.”
Seeing that he could produce yields “in the neighborhood” of those grown in conventional strawberry fields fumigated with synthetic fumigants, Hasegawa was able to expand his original 10 acres of organic strawberries to 50 acres.
“I guess you could say I'm kind of a convert,” he said, noting that he now applies ASD to all his acreage each year in late spring.
Joji Muramoto, UC Cooperative Extension specialist in organic production based at UC Santa Cruz, has been experimenting with ASD since it was first brought to the U.S. from the Netherlands and Japan in the early 2000s. Carol Shennan, a professor in the Department of Environmental Studies at UCSC, and Muramoto were among the first to try the technique in California. They found that ASD successfully controlled an outbreak of Verticillium wilt – caused by the pathogen Verticillium dahliae – at UCSC's small organic farm in 2002.
Since then, Shennan, Muramoto, Daugovish and their colleagues have seen encouraging results at 10 trial sites across the state.
“We demonstrated that ASD can provide comparable yields with fumigants, in side-by-side replicated trials,” Muramoto said.
ASD promotes host of beneficial changes to soil ecosystem
ASD comprises three basic steps: incorporating a carbon source that is easily digestible by microbes in the soil (traditionally, rice bran has been used), further encouraging fermentation by covering the soil with plastic to limit oxygen supply, and finally adding water through drip irrigation to initiate the “anaerobic” decomposition of the carbon source and maintain the three-week “cooking” process.
The resulting cascade of chemical, microbiological and physical changes to the soil creates an ecosystem that is both conducive to strawberry growth – and inhospitable to pathogens and weeds.
“It's not like a pesticide where you have a mode of action, and thus resulting in ‘A' and ‘B' for you,” Daugovish explained. “There's a sort of cocktail of events that happens in the soil; they all happen interconnectedly.”
Compared to similar fields that did not undergo the process, ASD-applied organic strawberry fields across California have seen yields increase by 60% to 70% – and even doubling in some cases, according to Daugovish.
The UCCE advisor also shared the story of a longtime grower in Ventura County, who came to him with fields in “miserable” condition; they were plagued by one of the world's worst weeds, yellow nutsedge, and infected with charcoal rot, a disease caused by the fungus Macrophomina phaseolina. But after applying rice bran and following the ASD recipe, the grower saw phenomenal results.
“The only complaint he said to me was, ‘Now I have too many berries – we have to have more pickers to pick the berries!'” Daugovish recalled.
Via researchers' meetings, online resources, on-farm demonstration trials and word of mouth from peers, use of ASD by California strawberry growers has grown significantly during the past two decades. Tracking the purchase of rice bran, Muramoto estimated that about 2,500 acres were treated by the ASD-related practices in 2023 – covering roughly half of the 5,200 total acres of organic strawberries in California.
Muramoto directly links the growth of California organic strawberry production – which now comprises about 13% of total strawberry acreage in the state – with the increasing adoption of ASD.
“If you remove the acreage with the applied rice bran over the last 10 years or so, organic strawberry acreage is just flat,” he said.
Within the last decade, acreage of organic strawberries with ASD-related practices increased by 1,640 acres, which is a boon for air quality, human health and long-term soil vitality. According to Muramoto's calculations, that increase in organic acreage translates to a reduction of about 465,000 pounds of fumigant active ingredients that would have been used in growing conventional strawberries.
“There are hundreds of reports of acute illnesses related to fumigation in the record, so it's very important to find alternatives to fumigants,” said Muramoto, citing California Department of Pesticide Regulation documents.
Research continues to make ASD more economical, effective
The popularity of ASD has come at a price, however, for organic strawberry growers.
“There's more organic out there, and I think most of the organic guys are using it, so there's more demand on the rice bran; the price has been steadily going up every year, like everything else,” said Hasegawa, adding that he has been trying to decrease the amount of carbon while maintaining ASD's efficacy.
On top of greater demand from other growers and from beef cattle and dairy producers (who use rice bran as feed), the price also has increased due to higher costs in transporting the material across the state from the Sacramento Valley. So Daugovish and his colleagues – including Peter Henry, a U.S. Department of Agriculture plant pathologist – have been searching for a cheaper alternative.
“We all want an inexpensive, locally available, reliable, easy to use and functional carbon source, which sounds like a big wish list,” Daugovish said.
Carbon sources such as bark, wood chips, or compost are ineffective, as the crucial ASD microorganisms are choosy about their food.
“Microbes are just like cows; you can't feed them straight wood; they get pretty angry,” Daugovish explained. “And if you feed them something with too much nitrogen, they can't digest it – they get the runs. Microbes are the same way – you have to have the right proportion of stuff so they feel comfortable doing what they're doing.”
In search of an ideal replacement, researchers tried and ruled out grass clippings, onion waste, glycerin and coffee grounds. Finally, they pivoted to a material with properties very similar to rice bran: wheat bran, in the form of wheat middlings (also called midds, a byproduct of flour milling) and dried distillers' grain (DDG, a byproduct of ethanol extraction).
After field experiments in Santa Paula, the UC and USDA researchers found that midds and DDG were just as effective at controlling soilborne pathogens and weeds as rice brain – but at 25% to 30% less cost. Their results were published last year in the journal Agronomy.
“Not surprisingly, the wheat bran has worked almost exactly the same as rice bran,” Daugovish said.
He and Muramoto are now conducting trials with wheat bran at commercial fields, and the initial results are promising. Daugovish said the grower at one site in Ventura County has seen a 90% reduction in Macrophomina phaseolina, the causal pathogen of charcoal rot, in the soil – and an 80% to 90% drop in yellow nutsedge germination. They are waiting for final yield numbers after the coming summer.
While ASD has been beneficial to organic productivity and soil health, both Daugovish and Muramoto acknowledged specific limitations in suppressing the “big three” strawberry diseases: Verticillium wilt, Fusarium wilt and charcoal rot. In coastal areas with cooler soil temperatures, for example, ASD can actually exacerbate the latter two diseases, as the fungal pathogens feed on the rice bran.
“We know it works at warmer temperatures, but, practically, it's hard to do in coastal California,” Muramoto said. “It would be nice if we can find a way to suppress Fusarium wilt at a lower temperature, but we don't have it right now.”
That's why researchers emphasize that ASD is not a “silver bullet.” It's just one tool in the organic toolbox, which includes careful crop rotation, disease-resistant strawberry varieties and better diagnostic tests that help growers pinpoint outbreaks and make the application of various methods more targeted and more efficient.
And scientists will continue to optimize ASD to make it more effective and economical for growers in the different strawberry regions of California – from the Central Coast to the Oxnard Plain.
“We know it can work really well; it's just finding the most sustainable way to do this in our region,” Daugovish said. “We've got to just have an open mind and keep trying.”
/h3>/h3>/h3>Sixth graders advocate for physical activity upgrades at school
Tehama County students empowered by CalFresh Healthy Living, UCCE educator and teachers
It's not uncommon for high school or college students to speak up and seek to improve their school environment. But at Evergreen Middle School in Tehama County, more than 100 sixth graders led the way to create healthy changes at their school.
As part of their health classes during the 2022-23 school year, the students researched the availability of spaces for physical activity, developed a survey gauging their peers' health awareness and needs, analyzed the results and data, and made recommendations for improvements.
“We learned that there's not a lot of places – except for Evergreen Middle School and some other parks around [our community of] Cottonwood – that have many physical activity places that you can easily get to or have access to,” said Bailey, one of the students.
They were guided by Mario Monroy-Olivas, a nutrition educator with CalFresh Healthy Living, University of California Cooperative Extension in Tehama, Shasta and Trinity counties. Locally administered by UC Agriculture and Natural Resources, CFHL, UCCE is one of the agencies in California that teaches nutrition to people eligible for SNAP (Supplemental Nutrition Assistance Program) – referred to as CalFresh Food in California.
Working alongside Evergreen teachers Roxanne Akers and Albert Estrada, Monroy-Olivas challenged the sixth graders to tackle a “Youth Participatory Action Research” project – a yearlong, multi-step undertaking typically designed for older teens.
“The fact that we're doing it with these younger kids, starting a lot sooner, I think it's super impactful for them to know that, together, collectively they can make huge changes that will create positive outcomes – not just for themselves but for an entire community,” Monroy-Olivas said.
Middle school students speak up at school board meeting
In February 2023, eight class representatives presented their findings to the Evergreen Union School District Board of Education. Speaking before the five-member board for 20 minutes, the young people were naturally a bit nervous.
“It was a little nerve-wracking at first, but it wasn't that bad, once we got up there and got it over with,” said Lilah, one of the presenters. “Me and a couple of my friends were doing pep talks and practicing what we were going to say.”
The students showed a composite map that they drew from their classes' investigation of spaces for physical activity in the area, and shared a brochure that outlined their research and survey results. In a survey of more than 80 of their peers, 92% of respondents said they needed more access to physical activity equipment during class breaks, recess and lunch.
“The board members were super impressed with the students, coming to the school board and doing this,” Monroy-Olivas said. “They said they haven't had students doing this kind of advocacy work; for them, it was a really big deal.”
In the end, the young people made a strong case for more water-bottle refilling stations, badminton equipment and balls for other sports, and stencils for schoolyard activities like hopscotch, four square and snail (a type of hopscotch game).
“We got almost everything we asked for, and the project we're working on now is to help put in the things we asked for,” said Lilah, adding that, during this current school year, the students (now in seventh grade) are working on acquiring the stencils and paint.
More than just equipment, students gain skills and confidence
While the promise of new gear is exciting for the youth, they are acquiring something even more valuable and enduring – a sense that they are empowered to make a difference in their community, according to Janessa Hartmann, UC Cooperative Extension community nutrition and health advisor for Tehama, Shasta and Trinity counties.
“Yes, it's important to want to do stencils and hydration stations and have more equipment,” Hartmann said, “but the bigger impact for the students is that they think: ‘Now I know that my health is important, now I know how to advocate for myself, and now I know that I can do that.'”
Monroy-Olivas said he observed tremendous growth in all the students, and especially in the self-confidence of the class representatives.
“I grew as a leader because I used to be really shy and hated talking in front of people, but through this project we're doing, this has really helped me be able to talk in front of crowds – and listen to others,” Lilah explained.
In a survey at the end of the sixth-grade project, the percentage of youth who answered “Yes, most definitely” to the statement “I want to make a difference in making my school/community healthier” jumped from 19% before the project to 44% after. And that percentage of “Yes, most definitely” replies jumped from 6% to 31% for the statement “I can use research results to come up with solutions or recommendations for making my school/community a healthier place.”
“We learned to promote what we want and try to get it as much as we can, so we can get more physical activities and more people can be included,” said Brian, another student working on the project.
“It's important so when we get older, we know how to voice our opinions and let people know what we're thinking,” added classmate Brooklynn.
Wishing that he had such an opportunity when he was growing up, Monroy-Olivas said he feels the students now know the power of their voice.
“I wholeheartedly believe that's the biggest win out of this whole project, that they're learning how to advocate for their own voice and change,” he said.
/h3>/h3>/h3>Car fumes, weeds pose double-whammy for fire-loving native plants
Wildflower displays threatened
Northwest of Los Angeles, springtime brings native wildflowers to bloom in the Santa Monica Mountains. These beauties provide food for insects, maintain healthy soil and filter water seeping into the ground – in addition to offering breathtaking displays of color.
They're also good at surviving after wildfire, having adapted to it through millennia. But new research shows wildflowers that usually would burst back after a blaze and a good rain are losing out to the long-standing, double threat of city smog and nonnative weeds.
A recent study led by Justin Valliere, assistant professor in the UC Davis Department of Plant Sciences, found that native wildflowers and other plants that typically flourish following a fire were, instead, replaced by invasive plants on land that received the kind of nitrogen contained in vehicle emissions.
“Many native plants in fire-prone areas rely on fire, and some are entirely dependent on it. Some are even most abundant after a fire,” said Valliere, a UC Cooperative Extension specialist in invasive weed and restoration ecology. “But we found that these fire-following species may be especially vulnerable to the combination of nitrogen pollution and invasive plants.”
That's part of the reason why native plants in these mountains have been declining.
Seeds – banked in the soil and waiting to sprout
The problem faced by native plants can be compared to a drawn-down bank account: Funds withdrawn are not being replaced.
It starts with fire, an important ecological process, Valliere said. Flames burn through plants on the surface and return their nutrients to the soil. Seeds sleeping in the ground wait for the next rain to sprout, then use those nutrients to grow.
“Plant diversity is often highest in growing seasons immediately after a site burns,” he said.
But invading plants have many advantages over native ones. They often sprout earlier, grow faster and create more seeds, all while tolerating drought.
“They're like cheaters,” Valliere said. “They don't follow the same rules.”
Nitrogen, too, is an important piece of every plant's nutrition. They all get a fertilizing boost from nitrogen that floats up in vehicle emissions and falls to the ground. But the invaders use nitrogen and other nutrients to grow faster, winning the race for water and sunlight. As a result, fewer native plants reach maturity, producing fewer seeds that keep their populations thriving.
When the bank balance reaches zero
The 2013 Springs Fire gave Valliere a unique opportunity to study the combined impacts of wildfire and extra nitrogen. He and colleagues from UC Riverside and the National Park Service created test plots in the Santa Monica Mountains where the fire had burned. Then, they added nitrogen to the soil to mimic the amount and type that LA's smog would deposit. Over the study's three years, native plants that typically would have flourished after wildfire instead declined even faster in the plots with added nitrogen.
Native seeds sprouted, but didn't flower. Over time, the soil's bank of seeds drew down.
“Each seed has one chance to flower and reproduce,” Valliere said. “If a seed grows and gets outcompeted, that seed has lost its chance to replenish the seed bank.”
Without the chance to replenish their bank account, native plants will die out, and the whole ecosystem will be thrown out of balance.
“There is inherent value in biodiversity,” Valliere said. “These invasive weeds could prevent the re-establishment of native shrubs after fire, sometimes forever altering the plant community.”
The loss of native plants can have cascading effects on the larger environment, he added. Problems can include the loss of native bees that feed on the flowers, and mudslides when rain makes hillsides unstable.
This problem is likely to repeat in similar areas where biodiversity is highest after wildfires – including parts of the Mediterranean basin, southern Africa and Australia. The addition of city smog “could have serious consequences for the biodiversity of fire-prone ecosystems worldwide,” Valliere warned.
Read the paper, “Nitrogen deposition suppresses ephemeral post-fire plant diversity,” by Justin Valliere, Irina Irvine and Edith Allen.
This article was first published on the UC Davis Department of Plant Sciences website.
/h3>/h3>/h3>Google Weed View? Professor trains computer to spot invasive weed
Algorithm for AI enables low-cost tracking of invasive plant
To manage johnsongrass, a noxious weed that crowds out cotton and sickens horses, farmers have tried herbicides, burning and hand-pulling. Now, researchers at University of California, Davis, have developed a more high-tech weapon against the invasive weed: artificial intelligence and machine learning.
Using photos from Google's Street View database, UC Davis researchers have tracked down over 2,000 cases of johnsongrass in the Western United States for a fraction of the cost and time that it would take to do drive-by or other in-person surveys. They call their tool Google Weed View.
The advancement could help land managers easily and quickly survey for other problem plants.
“Once the model is trained, you can just go and run it on millions of images from Google Street View,” said Mohsen Mesgaran, an assistant professor in the Department of Plant Sciences at UC Davis. “We have huge flexibility, and its capability can be scaled up very quickly.”
The technique can easily be extended to other plant species. All that is needed is to label the new item in Street View photos and train the algorithm to identify that object in the images.
By providing location information, Google Weed View also offers an opportunity to examine how climate affects the growth and spread of weeds and invasive plants at very large scales.
“I think it can be both useful for management and for people with interests in more basic questions in ecology,” Mesgaran said.
A colleague's query
Mesgaran began looking at using Google's photo database of roadways, streets and highways after Kassim Al-Khatib, a professor of Cooperative Extension in the same department, asked if he could survey Western states for johnsongrass.
Al-Khatib studies where johnsongrass grows, ways to manage it and how this perennial has evolved to be so prevalent and resilient. He's also working with scientists at the University of Georgia to decode the genome of johnsongrass, which is one of the top 10 most invasive weeds worldwide.
Johnsongrass can crowd out native plants, harbor pathogens and affect agriculture. It grows up to 7 feet tall with flowers that are green, violet, dark red or purplish brown depending on maturity, according to a UC Statewide Integrated Pest Management Program briefing page.
“Johnsongrass is a major weed not just in California but worldwide,” Al-Khatib said. “It's very difficult to control. It's a problem on vineyards. It's a problem for cultivated crops. It's a problem on orchards.”
Google Weed View allows for rapid, convenient scanning. It is continuously updated via everyday users with compatible cameras and images collected by Google. “Instead of a day of in-person driving, we can use AI to determine if johnsongrass is in a county or not,” Al-Khatib said.
Setting the parameters
To find the weeds, Mesgaran went to Google Street View, which hosts billions of panoramic photos. It didn't take long to find johnsongrass.
“The pictures are really good quality,” he said. “You can see plants and flowers.”
Street View's photos offer a 360-degree view, so in his request Mesgaran set parameters, based on street direction (bearing), to only see the side view. He also specified latitude and longitude, and other factors. To train the deep, or machine learning model, he chose Texas, where johnsongrass is prevalent.
A student sorted through over 20,000 images from that request to find pictures with johnsongrass and drew rectangular shapes around the weeds. They located 1,000 images.
The labeled photos were fed into a computer to train a deep learning algorithm capable of identifying johnsongrass in Google's images. The model was run again to capture potentially more images containing johnsongrass. These additional images were then labeled and used to further refine the model. With each iteration, the algorithm learned and became more accurate.
“This deep learning model was trained by these images,” Mesgaran said. “Once we had a semi-working model, we ran it against about 300,000 images.”
For Al-Khatib's request, researchers focused on 84,000 miles of main roads in California, Nevada, Oregon and Washington states. The team discovered 2,000 locations with johnsongrass.
Google Weed View cost less than $2,000 to purchase the images and teach the model. A traditional car survey to cover the same area would cost an estimated $40,000 in gas, hotel, food and other costs.
“In a matter of months, we came up with 2,000 records and I can do it for the whole U.S.,” Mesgaran said.
Next up? The entire United States.
This story was originally published on the UC Davis College of Agricultural and Environmental Sciences news site.