Posts Tagged: innovation

West Side REC study: A cradle of California regenerative agriculture

In 20-year study, UCCE specialist Mitchell, colleagues, growers advance no-till and cover cropping practices

In the 1990s, long before “regenerative agriculture” was a buzzword and “soil health” became a cause célèbre, a young graduate student named Jeff Mitchell first learned about similar concepts during an agronomy meeting in the Deep South.

Mitchell was astonished to hear a long list of benefits attributed to practices known internationally as “conservation agriculture” – eliminating or reducing tillage, cover cropping and preserving surface residues (the plant debris left after harvest). Potential positive impacts include decreasing dust in the air, saving farmers money on fuel and equipment maintenance, improving soil vitality and water dynamics and a host of other ecosystem services.

“All of these things start adding up and you kind of scratch your head and say, ‘Well, maybe we ought to try some of this,'” recalled Mitchell, who became a University of California Cooperative Extension cropping systems specialist at UC Davis in 1994.

In 1998, Mitchell launched a long-term study of those practices at the West Side Research and Extension Center (REC) in Five Points, Fresno County. “We started this because, way back when I first began my job, nobody was doing this,” he explained. “This was brand-new, uncharted territory for California.”

For the next 20 years, Mitchell and his colleagues studied changes to the soil and ecosystem, learned from their failures and successes, and shared those hard-won lessons with fellow scientists and farmers across the state. A summary of their findings was recently published in the journal California Agriculture.

Conservation agriculture in California: ‘No trivial undertaking'

Mitchell and the Conservation Agriculture Systems Innovation Workgroup – a network established in 1998 comprising farmers, researchers, public agency personnel and members of private entities and environmental groups – started with a virtually blank slate. According to Mitchell, surveys at the beginning of the 21st century found that conservation agriculture practices were used on less than one-half of 1% of annual crop acreage in California.

Although no-till is common in the Midwest and Southeast of the U.S. and across wide swaths of the globe, it was almost unheard of in the Golden State. With the development of irrigation infrastructure in the 1920s, California farmers saw continually phenomenal growth in yield over the last century – and thus had little incentive to deviate from tried-and-true methods that relied on regular tillage.

Nevertheless, intrigued by the potential benefits of conservation agriculture, Mitchell wanted to see which of those practices could be feasibly applied to California cropping systems. During the 20-year study at West Side REC, the researchers grew a rotation of cotton-tomato, followed by a rotation of garbanzo, melons, and sorghum, and finally tomatoes.

But at first, it was a struggle to grow anything at all – as they had to master the basics of how to establish the plants in a no-till, high-residue system.

“This was no trivial undertaking,” Mitchell said. “Early on we struggled – we failed the first couple of years because we didn't know the planting techniques and we had to learn those. There was an upfront, very steep learning curve that we had to manage and overcome.”

Then there was the long wait to see any measurable improvements to soil health indicators, such as the amount carbon in the soil.

“For the first eight years, we didn't see any changes whatsoever,” Mitchell said. “But then they became strikingly different, between the no-till cover crop system and the conventional field without cover crops, and the divergence between those two systems became even starker.”

The two-decade time horizon for the West Side REC study is one major reason why it has been so valuable for growers and scientists alike.

“It's so hard to capture measurable changes in soil health and soil function metrics through research because those changes are really slow,” said Sarah Light, UCCE agronomy farm advisor for Sutter, Yuba and Colusa counties and a co-author of the recent California Agriculture paper. “Often in the course of a three-year grant you don't actually get statistically significant differences.”

Reaching, teaching and learning from farmers

The study site on the west side of the San Joaquin Valley also has been a vital teaching resource. Even though Light works with farmers in the Sacramento Valley, she has conveyed findings from that research with her clientele and uses soil samples from the site to vividly illustrate a significant benefit of conservation agriculture practices.

In one demonstration, she drops soil aggregates – which look like clumps of soil – into two containers of water. One clump, from heavily tilled land, falls apart quickly and the water becomes dark and murky. The other, comprised of soil that has been no-till and cover cropped for 20 years, holds together – a sign of healthy, resilient soil – and the water remains relatively clear.

“It's a really simple demo, but it's very effective because it shows how easily soil aggregates break apart with water – or not,” Light said.

That aggregate stability is a key factor in soil's ability to both move water (infiltration) and hold onto water (retention). Those dynamics are crucial for farmers to avoid ponding in their fields, preserve water for drier months, and generally endure the flood/drought whiplash of climate change.

Over the years, Mitchell has hosted thousands of visitors at the West Side REC study site to showcase the potential benefits of adopting soil-health management practices.

“I don't think I'm exaggerating in saying that this is probably the most-visited agricultural field station project in the history of UC ANR (UC Agriculture and Natural Resources),” he said.

Both the West Side REC – and Mitchell himself – are greatly valued by the local grower community.

“Jeff is a microcosm of the university's applied research on the West Side of the San Joaquin Valley,” said John Diener, who grows almonds, fresh market garlic, canning tomatoes, cotton, masa corn and wheat for production and seed on land adjacent to the field station.

Growers adopt, adapt and adjust practices

Tom Willey, a retired farmer and longtime collaborator with Mitchell, has actively encouraged peers to visit the Five Points site – especially in the early years.

“It was very innovative and there weren't many examples of that anywhere in the state,” Willey said. “So, I helped encourage people to go out there and learn and possibly think about doing similar work on their own farms.”

Willey himself was a pioneer in experimenting with no-till practices in organic vegetable cropping systems.

“As organic farmers, we were probably more tillage dependent than conventional farmers because it was the only method we had for weed control; we weren't able to use herbicides,” Willey said.

Despite early struggles, he persisted in trying different techniques and mechanical means of weeding. And Willey later partnered with a group of progressive vegetable growers and UC and California State University Chico personnel to secure a Conservation Innovation Grant from the Natural Resources Conservation Service to support more on-farm trials and share their experiences.

In the end, however, no-till proved too risky to continue, given the losses they incurred. One tricky issue is nutrient cycling. The organic growers found that after mowing down a cover crop and spreading compost, leaving those nutrients on the surface without incorporating into the soil through more vigorous tilling (or adding synthetic fertilizers, as conventional growers could do) results in lower yields. In the short term, farmers simply did not see yields that could sustain their operation.

“It's very difficult in vegetable systems, and particularly difficult in organic vegetable systems,” Willey said. “I would say a number of us have learned to diminish the over-reliance that we had on tillage, but not to completely eliminate it.”

Cover cropping is also a challenge for some farmers, with certain cover crops making a perfect haven for devastating pests such as lygus bugs and stink bugs, according to Diener.

“We do everything we can to eliminate the host crop from which they come, so why am I going to bring the enemies to my house?” he said. “It's about making enough money to be there next year. You're not going to be there next year with these pests. It's just not a practical management option, in light of our significant pest pressure and disease hosts for our crops of value.”

Instead of planting cover crops, Diener said he opts for mixing in grain crops that can similarly contribute to soil health – while generating revenue at the same time. According to Diener, a longtime collaborator with Mitchell, the best way to adopt conservation agriculture practices is to tailor them to specific localities and each grower's circumstances. And in his corner of the San Joaquin Valley, that means not following the template of the high-precipitation, no-till systems found in the Midwest.

“We've adapted Jeff's principles to our program; it won't look like Iowa to you, which is what everybody comes to expect to see. It ain't how it works, folks,” Diener said. “It's a different methodology. We do those things that fit our environment and that's why that West Side field station is important – because it's our environment.”

Promoting and enhancing soil health, one step at a time

More widespread adoption of soil-health management practices can be driven by a variety of factors. With the rise of drip irrigation in tomatoes, for example, more growers began using no-till or reduced till to minimize disruptions to the delicate driptape in their fields.

And, according to Mitchell, the dramatic increase in no-till practices in dairy silage production – from less than 1% to over 40% – was the result of entrepreneurial efforts by a small but extraordinarily dedicated group from the private sector that worked with farmers, one by one.

Because optimizing these practices requires close and intensive attention – and no small amount of courage and gumption – Mitchell and Light understand that growers might need to take an incremental approach. Even one fewer pass over the field, or cover cropping every other year, can provide some benefit for soil health, Light said.

“The value is that when you can prove the concept, then you can motivate every step of the way,” Light explained. “Jeff is showing the shining light of the goalposts, and that can motivate us to take every challenging step along the way.”

Shannon Cappellazzi, who helped with the data analysis on the recently published California Agriculture paper, agrees that there is value in taking a stepwise approach in building soil health.

Cappellazzi was the lead project scientist on the Soil Health Institute's North American Project to Evaluate Soil Health Measurements, which looked at 124 different long-term soil research sites across the continent – including the Five Points site.

After analyzing 2,000 samples from the various study sites, Cappellazzi said the evidence suggests that layering on each component of a conservation agriculture program – doing no-till, adding cover crops and then integrating livestock, for example – can have additive, cumulative benefits for soil health.

“I think having the data to show the long-term benefit makes people willing to do the short-term change, even if it's a little bit hard for a couple years,” Cappellazzi said.

The research at the West Side REC also produced another key takeaway.

“To me, what really stood out was that for most of the soil health indicators, cover crops had a huge impact. Both the cover crops that had no till – and the cover crops that had standard tillage – had considerably higher carbon and soil health indicator measurements than those without cover crops,” said Cappellazzi. She added that the data also indicated improvements in how the water moved into the soil, and how the soil held that water.

Vital research drives an enduring legacy

Water management and conservation, of course, will be paramount in California's increasingly volatile climate reality. Mitchell's Five Points research – and related studies across the San Joaquin Valley by UC Davis agroecologist Amélie Gaudin and others – contributed data that overturned a long-held belief about winter cover cropping.

“There's a lot of preconceived ideas about cover crop water use,” Mitchell said. “One of the things that we learned was that compared to bare soil water loss in the wintertime, cover crop water loss during that same growing period – from about November through March – tends to be almost a wash.”

That crucial finding provided researchers and soil health advocates with invaluable evidence to preserve the practice as an option for farmers.

“They've needed to go around and give a dog-and-pony show to a lot of Groundwater Sustainability Agencies (GSA) that had been on the brink of banning the growing of cover crops because the perception out there is that they use a lot of water,” said Willey, the retired vegetable grower. “But over the winter months, cover crops don't use a lot of water. In fact, they may not use any net water at all.”

The young researchers who studied cover-crop water use represent another important legacy of the Five Points study site. It has been an experiential training ground for many of the next generation of soil scientists, agronomists and ecologists.

“The number of students who have been trained by and through this study has been really phenomenal,” said Mitchell, noting that they have worked on topics ranging from air quality to soil carbon related to no-till and cover cropping.

Their contributions will be essential in continuing to refine and optimize these practices that are fundamental to conservation agriculture. On Diener's concerns about lygus bugs and stink bugs, for example, Cappellazzi – in her new role as director of research at GO Seed – is studying and breeding cover crops with an eye on characteristics that make for less hospitable habitats for certain pests.

Indeed, while the California Agriculture paper effectively wraps up the 20-year study at Five Points, its lessons will continue to resonate and inspire for years to come.

“This is a step in a long journey,” Light said. “It's a launchpad – this paper might be able to tie a bow on it in terms of the data collection, but in terms of the extension impact, this is really just the beginning.”

And for Willey, the omnipresent climate crisis compels the entire sector to pick up the pace along that journey.

“We've got a lot of pressure now to evolve agriculture very rapidly in response to climate change and I don't think we can sit around and twiddle our thumbs,” he said. “We know the directions we need to be heading – with more natural systems mimicry and less reliance on toxic inputs and synthetic fertilizers – and we need to figure out how to incentivize and support farmers in moving in those directions.”

Green Hall of Famer Oki retires after 29-year UC career

UCCE specialist's research prevents water pollution, reduces water use

When interviewed to become a University of California Cooperative Extension specialist in environmental horticulture, Lorence “Loren” Oki was asked what kind of research he wanted to conduct.

In response, he showed the hiring committee a photo of a residential gutter. “Water is a big concern, and I found very little research on runoff from homes,” said Oki, explaining that studying residential runoff is what “started his career” with UC Agriculture and Natural Resources back in 2002.

Although he remains active supporting growers and advising industry leaders, Oki retired from UC ANR in July 2023. Before joining ANR, Oki worked as a researcher for UC Davis' Department of Environmental Horticulture studying greenhouse irrigation in 1994, bringing his total time with the University of California to 29 years.

Oki, professor emeritus of Cooperative Extension at UC Davis, led many research projects that advanced the green industry which includes landscapes, nurseries and floriculture.

“Loren is the epitome of a specialist,” said Darren Haver, UC ANR's Research and Extension Center system director, who has worked with Oki for more than 20 years on projects that have  significantly improved urban water quality and water conservation efforts across California.

Research influences pesticide management statewide

With a $3 million grant funding a statewide study, Oki and Haver set out to characterize runoff from residential sources over a five-year period. They determined the volume of irrigation runoff from residential land use, as well as the pollutants in the runoff.

Oki and Haver, co-principal investigators, along with researchers from UC Davis and UC Riverside, discovered that the degradation products of the insecticide fipronil – commonly found in runoff water – were more toxic than its parent compound. The study led to an investigation of human pathogens and pathogen indicators in residential runoff, the first of its kind.

Another contribution was the early detection of a new pesticide used for ant control, enabling strategies to be put in place to prevent it from reaching local streams and creeks. Oki and Haver's work also persuaded the California Department of Pesticide Regulation to change pesticide labels to minimize the chances of pesticides moving off target during irrigation and rain events. 

These changes included preventing pesticide application before predicted rain and preventing irrigation after applications, keeping pesticides from impervious surfaces, and restricting applications on lawns and landscape beds within two feet of impervious surfaces and others.

Plant trials expand beyond California

Oki was also the principal investigator of the Climate-Ready Landscape Plants project, which may be the largest irrigation trial in the western U.S., and the UC Plant Landscape Irrigation Trials, the California component of that project. The UCPLIT trials originated in 2004 at UC Davis as a research project by Karrie Reid, retired UCCE environmental horticulture advisor for San Joaquin County, while she was pursuing her master's degree. In 2017, the irrigation trials were duplicated at the South Coast Research and Extension Center.

These projects evaluate landscape plants under varying irrigation levels to determine their optimal performance in regions requiring supplemental summer water. Throughout the trial, Oki identified many landscape plants, including rose cultivars, that remain aesthetically pleasing with little water.

Today, the trials have expanded beyond California as the Climate-Ready Landscape Plants Project at Oregon State University, University of Washington, University of Arizona and Utah State University.

Growing up in the nursery industry

In 2017, Oki obtained tenure, allowing him to expand his professional responsibilities to include production horticulture, specifically greenhouses and nurseries, an industry he was extremely familiar with. “I come from a nursery family,” Oki explained. “My grandfather started Oki Nursery in the early 1900s.”

During World War II, Oki's family was incarcerated in the Poston Relocation Center in Arizona and lost their homes and property. When they were released, they returned to the nursery industry to rebuild their lives. “After World War II, my father and uncle got more involved with my grandfather's work,” he said.

The Oki family played an instrumental role in technological development for nurseries in general. Oki Nursery, which was located in Sacramento, worked closely with IBM and was the first to use a computerized system in the industry.

Oki developed computerized scheduling for the bedding plants, poinsettias, chrysanthemums, bulbs and other crops.  He developed a method to calculate the cost of any crop grown by the nursery at any point in the crop cycle and computerized greenhouse environmental and irrigation controls. This may not sound impressive now, but that was in the 1980s.

“My father was known for being progressive and he also knew everyone at UC Davis,” said Oki. “He wanted to work with anyone who had an interest in doing something good for nurseries.”

Inducted into Green Industry Hall of Fame

In the 1950s, Oki Nursery partnered with researchers from UC Davis' agricultural engineering program and developed the overhead sprinklers commonly used in nurseries today. Until the 1980s, Oki Nursery was the largest nursery in Northern California. Before it shut down in 1993, Oki worked in the family business as a greenhouse manager when runoff became a growing concern.

“I remember getting served with a notice by the Regional Water Quality Control Board stating that we needed to prevent runoff because it was polluted with nitrate fertilizer, which was common in the nursery industry,” Oki said.

One of those efforts focused on using controlled-release fertilizer instead of applying fertilizer via irrigation as a liquid feed. “What we learned is that if we converted nurseries to controlled-release fertilizer, we could reduce the nitrate runoff,” he said. While a member of the Oki Lab, Bruno Pitton earned his Ph.D. studying nursery hydrology and the fate of nitrogen fertilizers in container crop production adding to the information on runoff and nitrate management. Pitton is now the environmental horticulture advisor for Placer and Nevada counties.  

In 2023, Oki was inducted into the Green Industry Hall of Fame, which recognizes individuals with a minimum of 20 years in the landscape, nursery or floriculture industry and who have made significant contributions to the field.

Having grown up in the industry, Oki said that his father taught him to never be afraid to try new things. “If you think you have an idea that might work, do the best you can to make it work. If it doesn't work out, then it doesn't work out. And that's OK,” he said.

Revitalizing space for greater impact

This mentality encouraged Oki whenever tackling new tasks, like rebranding the California Ornamental Research Federation, a space for education and collaboration, as UC Nursery and Floriculture Alliance.

In 2009, Oki and David Fujino, executive director of the California Center for Urban Horticulture, became co-directors of CORF, which catered to the cut flower industry. At that time, Oki and Fujino realized that nurseries generated much greater revenue in the state than cut flowers.

“It was a strategic decision to change CORF to UCNFA, which included floriculture and nurseries in the name,” Fujino said. Combined, nurseries and floriculture have consistently placed in the top five agricultural commodities in the state.

When reflecting on their partnership, Fujino said that working with Oki was a “natural fit.” “I couldn't have asked for a better partner, a better colleague and, ultimately, a better friend to have my back and work side by side,” he added.

Since UCNFA's launch, the two have worked to maintain the group's impact by hosting “Ask your Advisor” webinars to connect advisors to growers, as well as co-hosting large-scale events such as the annual conference for the International Plant Propagators' Society — an organization focused on greenhouse and nursery production education — for the Western Region, which Oki's father helped establish in the 1960s.

Encouraging a return to education

Gerry Spinelli, UC Cooperative Extension production horticulture advisor for San Diego County and member of UCNFA's administrative committee, described those who have learned from Oki as his sons and daughters. “When I meet someone that's learned from Loren or worked with him, that person instantly becomes my friend. That's the kind of effect Loren has on us,” Spinelli said.

Grant Johnson, UC Cooperative Extension urban agricultural technology advisor for Los Angeles and Orange counties, credits Oki for his master's degree in horticulture from UC Davis.

“Loren gave me a lot of direction as far as career choices and research interests. He instilled in me a dedication to life-long learning, just like he continues to do,” said Johnson. Before Oki became his professor, Johnson worked with Oki as a staff research associate at the South Coast Research and Extension Center in Irvine.

Another influential person in Oki's life is John Kabashima, emeritus environmental horticulture advisor for UCCE Orange and Los Angeles counties and fellow Green Hall of Fame inductee. Like Oki, Kabashima grew up in the nursery industry.

Oki, who earned a bachelor's degree in ornamental horticulture from Cal Poly San Luis Obispo and a master's degree in plant science from UC Riverside, decided to pursue a Ph.D. in ecology at UC Davis with Kabashima's encouragement.

While Oki was still working in his family's business, Kabashima said that Oki relied on UC ANR researchers for scientific information and felt like Oki wanted to be one of them. “I told him that he's a good nursery guy, but he's a better scientist,” said Kabashima. “His heart is in science.”

The two began working together as soon as Oki became a graduate student and have been colleagues and friends for nearly 40 years. “My favorite response from Loren whenever people ask him a question is, ‘It depends,'” Kabashima said. “It always leads to people opening up and giving more context. That's what Loren does, he gets you to think.”

Learn how to use drones to collect field data June 24-28

DroneCamp in Monterey County offers lessons in person and online

Want to learn how to use drones to map and collect field data? DroneCamp 2024 will be held at California State University, Monterey Bay in Marina on June 24-28. For people who cannot attend in person, there is also an online option available.

No experience is necessary. Training will accommodate beginners as well as intermediate users who want to learn more advanced flight, data processing and analysis skills. 

Now in its 8th year, DroneCamp is a five-day short course covering everything you need to know to get started using drones for mapping and research. The curriculum covers equipment, safety and regulations, flight planning, manual and autonomous flight, photogrammetry, data processing, data analysis, data management and research talks. 

New for 2024 is a concurrent track for educators. Within these breakout sessions, instructors will present topics and methods for teachers developing drone programs, and will discuss drone technology, safety culture and remote-pilot code of conduct.

DroneCamp is led by a team of 21 instructors from UCMerced, UC Santa Cruz, CSU Monterey Bay, UC Davis, UC Berkeley, UC Santa Barbara, Lakeland College, American River College and UC Agriculture and Natural Resources.

Participants attending the presentations in person will get hands-on experience in flight workshops, where they will have the opportunity to:

• Fly a variety of drone platforms
• Directly engage with instructors and other participants
• Expand their networks
• Gain access to all the software used throughout the week
• Explore the iconic Monterey Bay Area

Light refreshments, daily lunches and a Monday evening dinner social are included with in-person registrations. Participants must make their own lodging arrangements as housing is not available through campus.

Registration for in-person classes will close on June 5 or when capacity is reached. The registration fee is $1,200 for in-person participants, $700 for academics and students, and $120 for virtual participants. To register, visit https://bit.ly/DroneCamp2024.

For more information, see the agenda at https://dronecampca.org/2024-agenda, watch video highlights from 2023 or contact info@dronecampca.org. 

Innovators in academia gear up for VINE Build workshops

A series of VINE Build workshops aimed at equipping academic innovators with essential pathways to bring new inventions to market is being sponsored by The VINE, an initiative of University of California Agriculture and Natural Resources (UC ANR), in collaboration with Farmhand Ventures. These workshops are designed to empower participants with the knowledge and tools necessary to navigate the complex landscape of technology commercialization.

"These workshops represent a unique opportunity for academic innovators to gain invaluable insights into the commercialization process," said Gabe Youtsey, UC ANR chief innovation officer and founder of the VINE. "By bridging the gap between academia and industry, we aim to catalyze innovation and propel advancements in technology and agriculture so we can enjoy the benefits sooner."

The half-day sessions will explore various aspects of commercialization as a mechanism for technology transfer. Led by industry experts, the workshops will cover user-centered design principles, inclusive innovation basics, the role of commercialization in technology translation, commercialization strategies, intellectual property licensing, transitioning from academia to business, and the differences between non-dilutive and dilutive funding.

"For academics looking to make a real impact, these workshops provide an invaluable platform," said Connie Bowen, co-founder and managing partner of Farmhand Ventures. "By participating in these sessions, innovators have the opportunity to turn their great ideas into tangible products that address the big challenges facing our industry today."

People involved in applied food and agriculture research – including professors, graduate students, undergraduate students and others  – are encouraged to participate.

The workshops will be held across various locations in California on the following dates:

• Fresno: May 9, 8:30 a.m. - 2 p.m., Smittcamp Alumni Center, Fresno State
• San Diego: May 23, 8:30 a.m. - 2 p.m., Salk Institute Foyer, San Diego
• Davis: May 29, 8:30 a.m. - 2 p.m Physical Sciences and Engineering Library, Conference Room, UC Davis
• Santa Cruz: Date and location to be determined.

For more information and to register for the workshops, please visit: https://bit.ly/vine-build-workshop

Grape seeds, stems and skins can reduce dairy cattle emissions

Low-cost wine industry additive also improved feed efficiency and milk quality

Researchers at University of California, Davis, added fresh grape pomace left over from winemaking operations to alfalfa-based feed for dairy cows and found that methane emissions were reduced by 10% to 11%.

The preliminary findings could offer a low-cost sustainable pathway for vineyards to reduce waste while helping dairy operations maintain quality while cutting back on emissions of methane, which is a powerful greenhouse gas.

“This is the first time anybody has shown that this can work in California,” said Ermias Kebreab, an animal science professor and associate dean of global engagement at UC Davis. “You're reducing emissions, you're improving the quality and it may also reduce the cost of production.”

The pilot research project, which will be detailed in a paper later this year, also found that mixing in grape pomace improved feed efficiency and increased healthful fats, said Selina Wang, an associate professor of Cooperative Extension in small scale fruit and vegetable processing.

“We found that the feed with the additive of grape pomace changed the fatty acid composition of the milk and, in particular, increased the polyunsaturated fats, which are the main fats in grape pomace,” Wang said. “This suggests that supplementing the feed with an optimal fatty acid profile may have positive impact on the fatty acid profile of the milk and increase their health benefits.”

Symbiotic commodities?

In 2022, California was the leading dairy producer in the country, generating $10.40 billion in sales, while 90% of wine production came from the Golden State, with a market value of $5.54 billion.

Processing grapes for wine generates thousands of tons of waste in the form of grape pomace, which consists of leftover seeds, skins and stems. Dairy and livestock are responsible for more than half of the state's methane emissions, owed largely to cow burps.

They are the top two agricultural commodities in California, according to state production statistics, and reducing waste and emissions for both industries are key to the state meeting its climate goals.

Tannins for emission reductions

Wine grapes are high in fats and tannin, which is known to reduce methane emissions, so Kebreab sought to test if adding grape pomace to feed could have a positive effect while not adversely affecting production.

“It's a byproduct that's not being used much,” he said. “This is something that can be included in our efforts to try to reduce emissions.”

A mix of feed options

To do the research, scientists worked with Holstein dairy cows and gave the animals feed consisting of alfalfa, wheat, almond hulls, cottonseed and grain. After two weeks, the cows were split into three groups: A control group with no change in diet, another where the feed combination included 10% grape pomace and a third that received 15% grape pomace.

Every four weeks, the cow groups would change feed combinations.

They were fed twice daily by postdoctoral students and interns, and emissions were monitored daily. Milk production was documented in the morning and evening and milk samples were collected weekly to analyze for fat, protein, lactose and other measurements, which showed no differences between the control and other groups.

Methane and hydrogen emissions were reduced compared with the control group, suggesting that grape pomace reduced enteric emissions without affecting production.

“I think the dairy industry will be very interested in this,” Kebreab said. “Sometimes when you're using additives, they have palatability issues. With grape pomace, they absolutely love it.”

Next on the list is a trial with olive pomace and working to understand the mechanism that reduces emissions. “If we have a better understanding of the mechanisms, we can select the feed additive or a mix of feed additives to reduce dairy cattle emissions and make dairy milk healthier while making use of the agriculture byproducts,” Wang said. “There's a lot of room to grow in this space and we're excited about this work.”

The research was supported by the California Dairy Research Foundation.

This article was first published on the UC Davis news site.

 

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