Courtesy of UC Agriculture and Natural Resources

Roger Duncan, UCCE farm advisor in Stanislaus County, retires after 36 years

For more than three decades, tree fruit and nut growers have depended on the advice of Roger Duncan, UC Cooperative Extension pomology farm advisor in Stanislaus County, to improve their production practices. Duncan, whose research and extension program focused on almonds, peaches, grapes and other tree crops, retired July 1.

“Roger Duncan has been an extraordinarily relevant researcher for the predominant crops in Stanislaus County,” said Rep. John Duarte, owner of Duarte Nursery in Hughson. “His research has encompassed rootstock and variety selection, tree spacing, chemical inputs and spraying, fertilizers, pruning and replanting amongst other projects.”

Duncan began working for UC ANR in 1988 as a field assistant to Integrated Pest Management advisor Jim Stapleton after earning a master’s degree in plant science and plant pathology from Fresno State and a bachelor’s degree in the same subjects from UC Davis. In 1990, he became a UC Cooperative Extension in pomology farm advisor in Stanislaus County.

During Duncan’s tenure, the planted acreage of tree and vine crops has tripled in Stanislaus County to nearly 1,900 farms on over 230,000 acres. His research has helped to improve production efficiency through improved rootstocks, crop varieties and production practices.

“Roger provides growers with resources and tools on nutrition, sprays, nutrient deficiencies, calendars, costs, pest management and other horticultural practices,” Duarte said. “His work has had significant impact on the productivity and quality of almonds, peaches and grapes. Breeders, universities, nurseries, growers and marketers have all gained from the wisdom and dedication of Roger Duncan.”

Growing up in Modesto, Duncan wasn’t raised on a farm. “I had friends whose families farmed orchard crops, so I had some exposure,” he said. “I caught the Extension bug while working as a summer intern for the pomology advisors in the Stanislaus County UCCE office after I graduated with my B.S. That is what inspired me to return to school with the goal of being a pomology farm advisor.”

Reducing production costs

To help growers lower production costs, Duncan introduced orchard practices aimed at reducing hand labor and other inputs. As a result of his research, minimal pruning has become the norm in California almond production, reducing input costs and carbon output and increasing yield. He also improved monitoring and management techniques of established and invasive diseases and insect pests.

“The practical applications Roger brings to the grower community are invaluable,” said Mel Machado, Blue Diamond Almonds vice president for member relations and Stanislaus County almond grower. “His minimal pruning study stood growers on their heads. People had preconceived ideas about pruning. He blew that up. His research showed that after you get the tree’s frame, all you need to remove are the dead and occluded branches. With the market depressed, we needed to cut costs. He said, ‘You don’t need pruning.’ Now I’m growing bushes.”

Art Bowman, a crop adviser with Salida Ag Chem, agreed that Duncan’s pruning research had an impact. “Roger’s pruning trial that lasted over 20 years was a much-discussed subject among growers,” Bowman said. “Growers’ pruning practices definitely changed due to Roger’s research, with early emphasis on structural development and, later in the tree’s life, concentrating on tree accessibility and deadwood removal.”

In 1990, when Duncan joined UC Cooperative Extension, California had 408,700 acres of almonds, according to the California Agricultural Statistics Service. Now the state has over 1.5 million acres of almonds.

About 75% of the farms Duncan has served have 40 acres or less, farmed by “small” or “part-time” farmers, who needed to learn basic horticulture and pest management. Stanislaus County also is home to some very large, sophisticated growers, who Duncan has kept apprised of new technology.

“I believe that personal interaction offers the most memorable means of information transfer, which is why I held an average of 12-plus extension events per year, gave 18-plus extension presentations per year, and went on an average of over 75 individual farm calls per year,” Duncan said. He also provided information via videos, blogs, podcasts, radio shows, newsletters, news media and extension publications as well as commodity boards.

Along with Duncan’s research, Bowman has appreciated his availability. “Roger was always ready to take a call, make orchard visits and listen to a grower’s concern or problem,” he said. 

In 1997, Duncan began hosting twice monthly Tree & Vine Integrated Pest Management breakfast meetings for pest control advisers and growers to discuss current and potential pest threats. These meetings have continued for 28 years.

He speaks ‘farmer’

Machado attributes much of Duncan’s success to his communication skills. “His research is scientific and he speaks ‘farmer,’” he said.

Machado gave rootstock as an example. “Roger is my rootstock resource; he knows rootstocks better than anybody,” he said. “His rootstock trial is dirt simple. There’s a different rootstock every five trees. You can see walking down the row the differences in the rootstocks.”

From his field evaluations, Duncan identified a complex hybrid rootstock that is highly tolerant to ring nematode, bacterial canker and salt toxicity. He found other hybrid rootstocks that boost crop yield while reducing risk from soil chemistry and soil-borne disease challenges, enabling almonds to be grown in the marginal soils on the west side of the North San Joaquin Valley. To help growers choose the appropriate rootstock for their soil, he wrote a comprehensive ANR publication, made a video and worked with the UC Fruit & Nut Center to create an interactive rootstock comparison website.

Over the last 15 years, use of hybrid almond rootstocks has increased dramatically. Burchell Nursery now sells approximately 40% of their trees on hybrid rootstock compared to less than 5% of almond trees 15 years ago, and more than 95% of Duarte Nursery almond trees are on hybrid rootstocks, according to Duncan. 

“We’ve worked with Roger for years, back when he didn’t have a mustache and then when he had a mustache,” said Robert Longstreth, who grows almonds, walnuts and cherries.

“Roger does research in the area you need, not frivolous stuff that you don’t need,” said Longstreth, who has benefited from Duncan’s research on pruning, rootstocks, irrigation timing, plant nutrition and disease control. “He’s thought very highly of by almond growers. When he has something to say, people listen.”

The UCCE farm advisor has overseen long-term trials to learn how to design and maintain an almond orchard to capture early production, maintain long-term yields and maximize profits. “In the first 17 years of the orchard design project, I increased cumulative net profits by up to $14,000 per acre, including increased yield while reducing labor and carbon inputs,” Duncan said.

Influenced by Duncan’s tree-spacing research results, growers have increased almond tree density by 20% per acre statewide, leading to higher crop yields, longer-living orchards and better farm economic sustainability.

As California’s expert on almond rootstocks and almond orchard design, Duncan has taught the subjects for the UC Almond Production Short Course, was lead author on the UCANR publication “Almond Rootstocks,” wrote the rootstock chapter, and co-authored the orchard design chapter of the UC Almond Production Manual. He was invited to Chile, Spain and Australia to share his expertise with growers there.

Expanded programs for kids and gardeners

In addition to being a farm advisor, Duncan served as director of UC Cooperative Extension in Stanislaus County from 2011 through 2013 and again from 2017 through 2020. As the UCCE county director, he acquired new county funding to hire a 4-H youth development program representative in 2018 to provide more learning opportunities for local, underrepresented children.

That year, he also acquired county funding to hire a full-time Master Gardener coordinator and launched the first UC Master Gardener Program in the county.

“I felt very lucky to serve as an advisor in the same county where I was born and raised,” Duncan said. “I am most proud of the trust I have developed with the growers and other clientele.”

Professional awards

Recently, Duncan’s peers at UC ANR honored him with a Distinguished Service Award for his outstanding extension program, which gave growers the data and confidence to adopt orchard practices that have bumped up the productivity and economic value of California almond orchards.

The popular breakfast meetings to discuss pest management earned Duncan and his UC Cooperative Extension farm advisor colleagues the Entomological Society Award of Extension Excellence and the California Department of Pesticide Regulation’s IPM Innovator Award. The California Legislature also recognized the breakfast club’s commitment to sustainable pest management.

Recognizing Duncan’s extraordinary contributions, the university recently granted him emeritus status.

“I have a lot of respect for the other farm advisors, but Roger is at the top of the pile,” said Machado, who has served on Almond Board committees with Duncan and known him since he joined UC Cooperative Extension. “I’m going to miss him. You can absolutely count on him.”

Congressman and nurseryman Duarte added: “While he will be sorely missed by us in his role of pomology advisor for the University of California, we hope that he keeps his interest, and continues to influence the food production industry in the Central Valley.”

Courtesy of UC ANR News 

UCCE scientists study feasibility of specialty crops for small urban growers

The vacant lots around your neighborhood could be growing fruits and vegetables and making local produce more accessible – while reducing energy needed to transport and distribute the food. Could turning those empty lots into small farms also become opportunities for economic development?

To answer this question, a team of researchers from University of California Cooperative Extension in San Diego County are investigating the economic feasibility of growing high-value specialty crops in urban settings like vacant lots. The project – led by Eric Middleton, UCCE integrated pest management advisor for San Diego, Orange and Los Angeles counties – is currently in progress at The Flower Fields in Carlsbad, a seasonal attraction for locals and tourists.

Tucked away in the back of the field is the Small-Scale Urban Ag Demonstration Site where Middleton and his team established a small farm on approximately 17,000 square feet, starting fall 2023. Funded by the U.S. Department of Agriculture National Institute of Food and Agriculture, the farm is designed to evaluate containerized production both outdoors and under high tunnels.

Growers don’t necessarily need land, just space

High tunnels, also referred to as hoop houses, are semi-permanent structures that act similarly to greenhouses in providing a controlled environment. For the experiment, Middleton will compare cost, effort and durability of two types of high tunnels: one made of steel and the other out of PVC pipes.

“We want to give interested growers information on as many options as we can,” said Middleton, who explained that the project is motivated by the challenges of urban settings, including limited space and lack of arable land.

In the trial, they are growing turmeric, ginger and blueberries. The high-value crops were selected because of their potential to earn a profit. Data evaluating plant variety, soil mix, fertilizer, growth performance, yield and pest and disease pressures will be collected and reported when the project concludes in 2026.

As the crops develop in containers – blueberries in pots and turmeric and ginger in grow bags – Middleton pointed out the mobility aspect of the study, noting that growers don’t necessarily need land, just space.

Whether it’s a backyard or a rooftop, containerized production means easier transport, especially since vacant land doesn’t always remain vacant forever and urban lots may often need soil remediation. Growing in containers solves the anticipated problem of having to relocate.

Where to set up shop in San Diego County

Jan Gonzales, project coordinator and community education supervisor for UCCE San Diego County, is leading the effort to identify available urban land in San Diego County as well as the policies and procedures for growers to access these spaces.

Gonzales is collaborating with community members who are working on similar projects to identify space for prospective growers.

“This has been done before for different objectives and for specific areas in the region, but the information was either project-specific and not publicly available, or not easy to find,” Gonzales said.

Having spoken with people associated with previous or ongoing agricultural land mapping projects, Gonzales has agreed to coordinate and facilitate an advisory work group to discuss areas of potential collaboration and develop project efficiencies. She anticipates holding the first group meeting before the end of the summer.

A production guide to help community members re-create the project

The ideal audience for a study like this is anyone who wants to grow specialty crops, according to Lindsey Pedroncelli, interim director of UC South Coast Research and Extension Center in Irvine, who worked on the project alongside Middleton when she was a staff research associate with UCCE San Diego.

“If you’re a new grower or a grower who wants to diversify your crop production, what we’re learning here can be applied to you,” said Pedroncelli.

Pedroncelli has been instrumental in bringing the experiment to life and documenting its step-by-step workflow thus far. The production guide, which is being created as the study unfolds, will include instructions detailing how to replicate the experiment from the ground up. Currently, it contains information on how to design your farm, the materials to buy, building structures, irrigation setup and crop management.

The most intriguing open question, whether the operation is profitable, is the driving force behind the production guide and will certainly be addressed, Pedroncelli said.

Book a tour and visit the farm

When visiting the farm, you’ll encounter three varieties of blueberries: Star, Snowchaser and Misty. Snowchaser has been a top producer since it was planted in January, but the variety is known to be an early season producer.

Using only one variety of each, the turmeric and ginger were planted in late March-early April. With some unanticipated cold weather in San Diego County, both crops struggled when transitioning out of dormancy, leading to very slow progress, which the team is still navigating today.

Visually, Middleton and his team have noticed differences between the crops growing under the high tunnels versus those grown outdoors, although the data has not been analyzed to confirm or explain notable differences.

Attempting to demonstrate how to profitably grow high-value crops in urban settings using limited space and resources, Pedroncelli said she hopes this study will also encourage people to grow culturally significant crops for their communities.

To tour the Small-Scale Urban Ag Demonstration Site at The Flower Fields in Carlsbad, email Eric Middleton at egmiddleton@ucanr.edu with “Urban Agriculture Demonstration Site Tour” in the subject line.

To learn more about the project and its progress, visit https://ucanr.edu/sites/socalIPM/Small_Scale_Urban_Agriculture_Project_/.

Courtesy of Mike Hsu

Organic Agriculture Institute needs assessment refines how it can address pressing challenges

The explosive growth of organic agriculture in the U.S. – reflected in a 90% increase in organic farms from 2011 to 2021, according to U.S. Department of Agriculture statistics – has come at a cost for some farmers. With new farming operations increasing the supply of organic commodities, along with consolidation of buyers, growers report that their profit margins are not what they used to be.

Those market size considerations are among the challenges highlighted in a new report detailing the initial findings by the University of California Organic Agriculture Institute on the most pressing needs of the state’s organic sector. OAI gathered and analyzed data from 423 responses to an online grower survey, over 60 interviews with stakeholders across the organic community, and additional observations from farm visits and workshops.

The report describes other frequently mentioned systemic priorities, such as maintaining integrity of the term “organic,” developing a market for organic seeds, spreading consumer awareness, and alleviating the burdens of organic certification and reporting.

Shriya Rangarajan, the postdoctoral researcher with OAI leading this statewide needs assessment, said that the reported challenges varied by organic status (fully certified, transitioning to organic, or a mixed farm with some conventional), type of crop, as well as size of the operation. She noted survey respondents were roughly representative of the sector overall – 70% small-scale growers and 30% medium and large.

“Organic is not a homogenous industry, to say the least – small growers and large growers are very different; for small growers, their challenges tend to be financial and regulatory, especially relating to certification requirements and labor,” said Rangarajan. She added that larger growers mentioned different types of challenges, weeds and pest pressures for instance, given the difficulty in controlling managing these at scale without the use or availability of organic inputs.

Organic Agriculture Institute key to sharing resources across state

Another common theme from the assessment is that the organic sector needs more accessible resources to address those myriad concerns. For OAI, established in 2020 under UC Agriculture and Natural Resources, the initial findings validated and refined the direction of its research and extension programs.

“As a new organization, we’ve been trying to figure out where we fit into this ecosystem and how we can support it,” said Houston Wilson, a UC Cooperative Extension entomology specialist who has served as OAI’s director since its founding.

Because OAI was envisioned as a hub of resources and connections for California’s organic community, Wilson and his colleagues are especially interested in understanding how its constituent members obtain information – and how OAI can improve their access.

“Growers are finding it difficult to navigate the resources that exist for organic agriculture, like technical information, financial support, compliance and certification support,” Wilson said. “While we’d like to see more resources for organic in general, those that currently exist can sometimes be hard to navigate or it can be hard to know where to go for the right thing – that became really apparent early on.”

While some producers are contacting OAI directly with their questions, Wilson is eager to develop tools and systems that can serve the community more broadly. For example, Wilson and Krista Marshall – OAI’s policy and partnerships coordinator – are currently beta-testing a new map tool, built in conjunction with UC ANR’s Informatics and GIS (IGIS) team. The map, expected to be ready in fall 2024, will enable users to click on their county and see all available resources related to organic agriculture.

Wilson added that OAI will have four full-time staffers by fall, further expanding its research, extension, and education efforts. After holding four field events this past year, OAI aims to increase activities in the coming year, including not just field events but also online resources, webinars and more. Also, a new training and technical assistance coordinator will be tasked with bringing Cooperative Extension advisors and other technical assistance personnel across the state up to speed on a range of organic topics, so they can more effectively answer questions from clientele in their region.

New survey aims to trace crucial organic knowledge networks

Although the OAI team has gained a sense of how information is shared across the organic community (and started to formalize those interconnections through a California Organic Agriculture Knowledge Network), they are now developing a survey to study those relationships more systematically.

“We’re trying to understand what kind of knowledge resources people tap into, which is something that has come up repeatedly in our needs assessment,” Rangarajan said. “We’re trying to understand who people are speaking to because, at the end of the day, organic is still a relatively small part of agriculture in California, and that makes it more fragmented. So trying to connect those different parts becomes important.”

Once Wilson has a more nuanced understanding of organic knowledge networks, he will be able to strategize and position OAI – and the UC – as a more effective partner and contributor in the sector.

“Given the history of organic, growers have had to rely on each other a lot,” Wilson explained. “We understand that the university has unique expertise to bring to the table, but we also acknowledge that there’s all these other knowledge holders out there, so one of the roles that we see ourselves having is helping to facilitate those connections, strengthen them and increase the frequency of interaction.”

That may include further supporting efforts that connect transitioning organic farmers with experienced growers (a mentorship program led by Certified California Organic Farmers, or CCOF), or giving more structure to grower-researcher partnerships that can help address a host of production challenges. In OAI’s grower survey, weed management topped the list, followed by water and disease issues, all exacerbated by climate variability.

“I think a lot of the real innovation changes are coming through growers experimenting with their own practice,” Rangarajan explained. “From a research perspective, one of the best ways to take this forward would be to formalize those experiments in some way so that knowledge becomes more reportable.”

And collaboration on “organic topics,” such as finding alternatives to synthetic pesticides, are a boon to the entire agricultural sector – conventional growers included.

“Everyone is trying to reduce pesticide use; everyone is trying to reduce environmental impacts,” Wilson said. “You don’t have to be certified organic to benefit from organic research; these practices can be used by anyone.”

The report with OAI’s initial findings on organic needs can be found at: https://ucanr.edu/sites/organic/files/396228.pdf.

Courtesy of UC Agriculture and Natural Resources 

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:

1. What are the impacts of cover crops on water cycles (both benefits and use)?
2. How does SGMA management account for cover cropping and is it capturing cover crop benefits alongside their water use?
3. 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.