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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.”
/h3>/h3>/h3>/h3>/h3>/h3>Youth invited to Mustang Camp in Lassen County June 28-29
UC Cooperative Extension in Modoc County is partnering with Utah State University to offer a mustang camp for California youth ages 9 to 19.
The 4-H Mustang Camp, sponsored by the U.S. Bureau of Land Management, will be held on June 28-29.
This overnight camp is an opportunity for youth across California to learn about managing public lands, rangelands, wild horses and burros. Mustangs are feral horses that roam freely.
“We realize not everyone can take a wild horse home so we'll take the young people out on the range,” said event organizer Laura Snell, UC Cooperative Extension livestock and natural resources advisor for Modoc County.
“Participants will learn about range management, the grasses, habitat, ecosystem and wild horses,” she said.
Youth also will learn about careers with U.S. Bureau of Land Management and the U.S. Forest Service related to wild horse management.
Camp participants will spend the night at a campground and use facilities at the Lassen County Fair Grounds. Registration for the mustang camp is $75 and includes lunch and dinner on June 28 and breakfast and lunch on June 29. Space is limited to 25 youth.
“Our hope is that by participating in this camp these young people will leave understanding and appreciating the uniqueness of our wild horses and burros,” said Snell.
The 4-H Mustang Camp is sponsored by the BLM Wild Horse and Burro Program and UC Cooperative Extension in Modoc and Lassen counties. It will be held at Lassen County Fair Grounds at 195 Russell Avenue, Susanville, CA 96130.
Registration for camp is open through June 14. To learn more about the camp or to register, visit https://extension.usu.edu/utah4h/events/mustang-camp.
Colt Challenge on June 22
The public is invited to celebrate the five-year anniversary of the Devils Garden Colt Challenge on June 22 in Alturas in Modoc County. In the Colt Challenge, 4-H and FFA youth in California and in the Oregon border counties of Lake and Klamath take home young, wild horses in December to train, then gather in June to show their horses' progress. Attendance is free.
For more information about the Colt Challenge, visit https://www.devilsgardenucce.org/post/colt-challenge-faq.
Report: Wastewater recycling essential to resilient water future for LA region
Wastewater recycling in Los Angeles is the focus of a new report released by the UCLA Luskin Center for Innovation and the UC Agriculture and Natural Resources. The report, Making the Most of Landmark Recycled Water Investments in Los Angeles: Technical Advisory Recommendations for the Region, was commissioned by Los Angeles Waterkeeper. The goal of the report is to support ongoing efforts to improve local water security and rely less on expensive, energy-intensive and increasingly unreliable water imports from faraway places, like the Sacramento-San Joaquin Delta and the Colorado River.
Experts involved in developing the report agree that expanding the use of recycled wastewater has emerged as a key, scalable water supply strategy that can offer certainty and reliability in the region in light of our new climate reality.
“Both the Metropolitan Water District of Southern California and the City of LA's Department of Water and Power have made significant investments in wastewater recycling, and they plan to do more,” said Bruce Reznik, executive director of LA Waterkeeper. “But there are a lot of moving parts and some critical decisions to be made in the short term if we're going to make significant progress toward reliable local water supplies.”
“The purpose of this report is to help decisionmakers see the full picture so they can prioritize and develop informed strategies for expanding and integrating the disparate wastewater recycling projects into a more cohesive wastewater system – all while taking community voices and environmental impacts into account,” he added.
Local leaders recognize the region must further invest in equitable, climate-smart, affordable local water strategies. LA County's Water Plan, released in late 2023, calls for 80% of water to come from local sources by 2045 (compared with approximately 40% currently). Four major centralized wastewater recycling projects, including two that are landmark in size and scope, have either broken ground or are in the active planning stages throughout Los Angeles County. Collectively, this regional effort may represent the most important water supply investment in the American West in the last half century.
“In many ways, our region has taken great strides toward embracing wastewater recycling,” said report co-author Edith B. de Guzman, UC Cooperative Extension water equity and adaptation policy specialist. “But we need a clearer pathway for how these projects can be built and possibly integrated into a more cohesive system. This report provides a blueprint for water agencies on the project design, community engagement and governance steps that must be made to ensure progress toward rapidly increasing our local water independence.”
Upwards of $20 billion in investment in wastewater recycling projects is planned for the coming years. But as local water and wastewater agencies make these investments, it's essential that they design systems to both maximize benefits and minimize impacts that could be damaging to people and the environment, all while ensuring water remains affordable. Just as importantly, the report flagged the need to effectively engage the public in key decisions to foster public trust in these emerging water technologies and facilitate coordination between agencies to create a resilient regional water supply system.
Specific action items identified in the report are organized under eight principal recommendations:
- Take actionable steps on current key decision points pertaining to major recycling facilities. The report encourages agencies to make several decisions that will impact the design of the overall wastewater recycling systems imminently. These include resolving differences between the City of LA's Hyperion 2035 and Operation NEXT efforts, deciding whether to upgrade existing wastewater recycling infrastructure like the Edward C. Little Water Recycling Facility, and making key pipeline and routing decisions.
- Conduct a more nuanced regional analysis of system facilities, with an emphasis on evaluating distributed alternatives. While some assessment of a more distributed system has been undertaken, additional analysis is still needed on the issues of energy demand, the cost of distributing water under different alternatives, and impacts on aquatic and marine ecosystems.
- Identify and establish a structure for collaborative governance that enables agencies to work together to realize a regional advanced wastewater recycling network.
- Adopt a coordinated monitoring plan to ensure water quality is safeguarded for public and ecological health.
- Balance the adoption of Indirect Potable Reuse (IPR) and Direct Potable Reuse (DPR) with a near-term focus on IPR to the extent feasible and using DPR to fill in service gaps.
- Perform robust regional forecast and impact analyses to improve future-proofing of facility and network designs, maximize benefits, minimize harm, and avoid stranded assets.
- Design and execute a collaborative communication and community engagement strategy that offers a clear narrative, emphasizes the benefits of a secure water supply, meets the needs of water customers, and is delivered by trusted messengers.
- Coordinate across agencies on strategies to attract project financing while taking household affordability into account.
“This report is by no means the final word,” said co-author Gregory Pierce, research and co-executive director at UCLA Luskin Center for Innovation. “The point of this study is to provide guidance and spur discussion, and we hope and expect to see ongoing research and coordination on all of these issues.”
The report was informed by input from a Technical Advisory Committee of 20 people from fields including academia and think tanks, conservation advocacy, labor, the private sector, and current and former water district leaders not affiliated with the projects that are the focus of the report. This effort also benefited from the feedback and insight of more than 20 public agency representatives, including many from the City of Los Angeles (including Los Angeles Department of Water and Power and LA Sanitation and Environment), Metropolitan Water District of Southern California, Los Angeles County Sanitation Districts, Las Virgenes Municipal Water District, and West Basin Municipal Water District.
The full report is available at https://innovation.luskin.ucla.edu/wp-content/uploads/2024/06/Making-the-Most-of-Landmark-Recycled-Water-Investments-in-LA.pdf.
Report: Cover crops benefits may outweigh water-use in California
Additional guidance needed for groundwater management strategies
Cover crops are planted to protect and improve the soil between annual crops such as tomatoes or between rows of tree and vine crops, but growers may be concerned about the water use of these plants that don't generate income.
“Cover crops are one of the most popular practices we see farmers employ through our Healthy Soils Program,” said Karen Ross, secretary of the California Department of Food and Agriculture. “Cover crops supply a host of benefits, such as helping to protect against soil erosion, improving soil health, crowding out weeds, controlling pests and diseases, and increasing biodiversity; and they can bring increased profitability as the number of other inputs are reduced. They also provide water benefits such as improved infiltration and reduced runoff.”
These potential benefits are especially salient in the San Joaquin Valley, where groundwater challenges are more acute. A new report evaluates the water implications of cover cropping practices to lay the groundwork for their adoption in the context of the Sustainable Groundwater Management Act, or SGMA, which is intended to protect groundwater resources over the long-term.
“Yes, cover crops require a nominal amount of water to establish – and sometimes rainwater is sufficient – but the myriad co-benefits are worth it,” Ross said.
Growers, water resource planners and managers, crop consultants, irrigation practitioners and policymakers may find the cover crops report useful.
The report is the product of a convening process jointly developed by the California Association of Resource Conservation Districts, CDFA, Natural Resources Conservation Service of California, and University of California Agriculture and Natural Resources, and assembled by nonprofit Sustainable Conservation.
The multidisciplinary group of more than 30 individuals has published “Cover Cropping in the SGMA Era.” The literature review, policy analysis and recommendations pertain to the water impacts of cover crop practices in California's Central Valley under SGMA.
Cover crops and their potential
“Wintertime rain-fed cover cropping does not necessarily significantly increase water losses compared to bare ground in the winter months,” said co-author Daniele Zaccaria, associate professor in agricultural water management for Cooperative Extension at UC Davis. “Cover cropping can significantly improve soil-water dynamics, increasing soil water infiltration and storage and reducing surface runoff.”
To reap the benefits of cover crops using minimal water, Zaccaria said growers will need to know how the plants perform under different conditions.
“We need to develop and implement a coordinated research effort to increase understanding of net water impacts of cover crops under various meteorological conditions – dry, wet, average," he said.
Report findings and recommendations
To understand the potential of cover cropping under SGMA, the report's authors came together to answer the following questions:
- What are the impacts of cover crops on water cycles (both benefits and use)?
- How does SGMA management account for cover cropping and is it capturing cover crop benefits alongside their water use?
- How can we ensure that this practice remains available to growers where and when it makes sense?
This report synthesizes the learnings from the collaborative initiative including 100-plus multidisciplinary experts, a policy analysis, interviews with Groundwater Sustainability Agency (GSA) staff and consultants, and the expertise contributed by its 30-plus authors. In light of these findings, the report advances a series of recommendations aimed at bridging critical knowledge gaps, enhancing the integration of cover crops into policies and incentive programs, and bolstering data infrastructure and other mechanisms to support sustainable groundwater management initiatives.
One vital throughline is the need for additional guidance from the state to support local GSAs in facing the complex challenges of developing and implementing groundwater management strategies for their local watersheds. These measures aim to optimize cover crop integration within SGMA frameworks and promote sustainable water management practices crucial for the region's agricultural resilience and environmental health.
“This report is unique because the university collaborated closely with state agencies and private sector partners to ensure that the different perspectives provided both the best science available as well as viable policy options,” said Glenda Humiston, University of California vice president for agriculture and natural resources. “By taking a comprehensive view, we can advance recommendations for cover crop policy that help us meet multiple goals, manage our natural resources more effectively, and avoid unintended consequences.”
Sarah Light, UC Cooperative Extension agronomy farm advisor, is one of the UC ANR experts who provided science-based information during the convening sessions and co-authored the white paper.
“Cover crops are a valuable soil health practice that can help ensure the resilience of California farms to climate extremes,” said Light. “As we balance the complexities of water and soil management, it is important to understand the role that cover crops play in an annual water budget so that they are not disincentivized in certain parts of the state. This paper can provide guidance to GSAs and policymakers who are charged with implementing SGMA in their regions.”
The report “Cover Cropping in the SGMA Era” can be downloaded for free at https://suscon.org/wp-content/uploads/2024/05/SC-Cover-Crop-SGMA-Report.pdf.
Related research links:
Long-term reduced tillage and winter cover crops can improve soil quality without depleting moisture https://escholarship.org/uc/item/1cr6w7dp
Impacts of winter cover cropping on soil moisture and evapotranspiration in California's specialty crop fields may be minimal during winter months https://californiaagriculture.org/article/108637
Water-related impacts of cover cropping in California https://www.youtube.com/watch?app=desktop&v=mTNLx6LzEt0
/h3>Groundwater demand management subject of discussions June 17
Groundwater demand management in agricultural regions is the focus of a workshop that will be held June 17, from 9 a.m. to 3:30 p.m., at the Hyatt Regency San Francisco Airport in Burlingame.
Representatives of groundwater sustainability agencies (GSAs), water districts, irrigation districts, government agencies, environmental justice organizations and the private sector and growers and researchers will discuss groundwater demand management from their own perspectives.
“Speakers will discuss policy development, stakeholder engagement and funding considerations for groundwater demand management,” said workshop co-organizer Isaya Kisekka, UC Davis professor of hydrology and agricultural water management and director of UC Davis Agricultural Water Center. “Participants also will discuss available tools and technologies for implementation and monitoring of groundwater demand management programs.”
The agenda is posted at https://ucanr.edu/sites/groundwaternitrate/files/398036.pdf.
Registration for the workshop is free. Register at Groundwater Demand Management Workshop Registration.
This is one of three free workshops – managing groundwater nitrate, groundwater demand and groundwater governance – being offered before the "Toward Sustainable Groundwater in Agriculture - Linking Science and Policy" conference June 17-20 https://ag-groundwater.org.