California Ag Network

Tag: UC Davis

  • UC Davis Launches $3 Million Project to Improve Farmworker COVID Safety

    California’s 800,000 farmworkers have been hit hard by COVID-19, the disease that has infected more than 25 million people and killed more than 420,000 in the United States. Farmworkers are especially vulnerable to the airborne virus that causes COVID-19 because they often live, work and carpool in close quarters with other people. As essential employees, farmworkers have stayed on the job during the pandemic to plant, process and harvest the nation’s food.

    Agricultural safety experts and communicators at the University of California, Davis, have launched the COVID-19 Statewide Agriculture and Farmworker Education Program to reverse that trend. Funded by a $3 million contract with the California Labor and Workforce Development Agency, the project provides workers, growers, farm labor contractors, community groups and others the training and safety information they need to reduce farmworkers’ risk of contracting COVID-19.

    The COVID-19 project is led by experts at the UC Davis Western Center for Agricultural Health and Safety, who are collaborating with the UC Davis College of Agricultural and Environmental Sciences Communications Team, a network of community-based organizations, and agricultural industry groups.

    “Our team will work directly with community organizations who are trusted by farmworkers and have already been assisting them throughout this COVID crisis,” said Heather Riden, program director at the Western Center for Agricultural Health and Safety. “Our goal is to amplify their efforts and help them build capacity as they continue to provide critical COVID safety information to their communities.”

    The team is also working closely with farmers and others in the agriculture industry as they navigate state COVID-19 workplace safety standards, establish protocols and provide employees the tools they need to stay safe on the job.

    “As employers across the state implement that new COVID-19 Emergency Temporary Standards, we want to be a resource for them so they can take all the necessary steps to ensure a safe work environment,” said Riden.

    The program will be especially active in areas of high agricultural employment, such as the Central Valley, the Imperial Valley, Napa Valley and fertile regions along California’s south and central coastlines.

    Free trainings and other events are already underway. You can learn more and register for upcoming presentations on the UC Davis Western Center for Agricultural Health and Safety website. The center also offers extensive COVID resources and information in multiple languages on its COVID-19 Resources page. — By Diane Nelson, UC Davis

  • New Walnut Variety to Allow Earlier Harvest

    University of California, Davis, researchers have bred a new walnut variety designed to provide growers a way to harvest earlier and boost the harvest efficiency of California’s $1.6 billion walnut industry. The new “UC Wolfskill” walnut has yield, quality and light color similar to Chandler, which is a late-harvesting walnut and the state’s leading variety. UC Wolfskill was bred in 2003 from a cross of Chandler with the Solano walnut. UC Wolfskill combines the color and shell traits of Chandler with the earlier harvest date and kernel fill of Solano.

    “The release of UC Wolfskill means growers can spread out their harvest and still have a really high-quality nut that will fetch top-notch prices and provide similar yields,” said Pat J. Brown, breeder and professor with the UC Davis Department of Plant Sciences.

    Over 99 percent of the nation’s walnuts are grown in California. More than half of the state’s bearing acres are the late-harvest Chandler walnuts. “The California walnut industry needs earlier harvesting walnut varieties to provide efficient use of harvesting, drying and processing equipment,” said breeder Chuck Leslie, with the UC Davis Walnut Improvement Program. “UC Wolfskill can be harvested 12 to 14 days earlier than Chandler and provides consistently light to extra light color.”

    Handlers judge the value of a walnut based on its color and how well it halves while processing. In blind quality evaluations by commercial graders, the UC Wolfskill was often not distinguished from Chandler.

    UC Wolfskill was originally planted and evaluated at UC Davis, and field trials with growers began in 2011.

    “The commitment of our walnut growers, as collaborators, is the foundation that makes this release possible. The Board is extremely grateful for the long-term partnership of our growers and the UC, in finding innovative solutions that help us solve for critical needs,” said Michelle Connelly, executive director of the California Walnut Board.

    The California Walnut Board funded the research. UC Wolfskill is currently available to California nurseries for propagation in California and sales to growers throughout the United States. Nurseries interested in propagating and selling this cultivar may obtain a license from UC Davis InnovationAccess. – By Amy Quinton, UC Davis Food & Ag

    “Editor’s Note: Photos Provided by Janine Hasey, UCCE Farm Advisor Emeritus”

  • Director of the UC Kearney Research & Extension Center Retires

    Jeff Dahlberg, UCCE Specialist & Director of the UC Kearney Agricultural Research & Extension Center (KARE) in Parlier

    UC Cooperative Extension specialist Jeff Dahlberg, also the director of the UC Kearney Agricultural Research and Extension Center (KARE) in Parlier, invoked his 35 years of sorghum expertise to increasing interest in growing the crop in California and to better understanding plants’ ability to tolerate drought. Dahlberg retires Jan. 8.

    As a Peace Corps volunteer in Niger in the early 1980s, Dahlberg was intrigued by sorghum, a staple food being cultivated by the country’s vast population of subsistence farmers.

    “I was impressed with the fact that sorghum was so drought tolerant,” Dahlberg said. “Nigerien farmers relied solely on rain for their sorghum and millet crops.”

    Upon returning to the U.S., he earned a master’s degree at the University of Arizona and a Ph.D. at Texas A&M, where his research focused on sorghum. He worked with the USDA Agricultural Research Service in Puerto Rico for 7 years and then spent the next 10 years as research director with the National Sorghum Producers in Lubbock, Texas.

    When Dahlberg took the helm of the 330-acre UC agricultural research center in 2010, he and colleagues at the UC West Side Research and Extension Center and at UC Davis began conducting sorghum forage variety trials. Sorghum wasn’t new to California. In the past, it had mainly been used for animal feed. But Dahlberg believed the crop’s adaptability – excellent for forage, biofuels and gluten-free human food – offered the grain a rosy future in the Golden State.

    “With our research, we have provided California farmers who are thinking about growing sorghum access to locally generated, research-based information to help them make the decision,” Dahlberg said.

    Jeff Dahlberg, center, with a delegation of Chinese sorghum scientists on Sept. 24, 2015, in a sorghum field at Kearney.

    In 2015, Dahlberg and UC Berkeley specialist Peggy Lemaux launched a sweeping drought research project at KARE. The five-year study, funded with a $12.3 million grant from the Department of Energy, researched the genetics of drought tolerance in sorghum and how soil microbial communities interacted with sorghum roots to battle drought stress.

    A journal article published in Proceedings of the National Academy of Sciences in 2018 presented the first detailed look at the role of drought in restructuring the root microbiome. The plant switches some genes on and some genes off when it detects water scarcity and access to water.

    “That has implications for feeding the world, particularly considering the changing climate and weather patterns,” Dahlberg said.

    In recent years, Dahlberg helped reestablish tea research at Kearney, initiated nearly 60 years ago in a study funded by Thomas J. Lipton, Inc. At the time, Lipton was seeking to grow tea for the instant tea market. When the Kearney tea research program was scrapped in 1981, a researcher had a handful of the best tea clones planted in the landscape around buildings at Kearney.

    Those shrubs became the basis for a new tea research trial planted at Kearney in 2017 with UC Davis professor Jackie Gervay Hague to determine whether drought stress impacts the production of phenolics and tannins in the tea.

    “We know we can grow good tea here and we can grow high tonnage,” Dahlberg said. “We want to determine if we can do that on a consistent basis and whether we can improve tea quality through irrigation management.”

    In retirement, Dahlberg plans to relocate to Lake Ann, Mich., to be close to family. UC Cooperative Extension irrigation specialist Khaled Bali will serve as interim director of the UC Kearney Agricultural Research and Extension Center. — By Jeannette Warnert, UCANR

  • Almond Ganoderma Butt Rot Spore Survey

    Ganoderma butt rot has been an increasing problem in the almond industry. The disease has been responsible for trees falling over all throughout the Central Valley. Ganoderma butt rot is caused by wood decay fungi that can spread via spores in the air. In order to better focus our management efforts, researchers must conduct a spore survey that will help us determine the times and locations that are at greatest risk of infection and spread by spores.

    The survey will include collecting air samples at almond orchards once a month for 2 years, so it will require long-term cooperation, but will be non-invasive and will not interfere with management practices. Any almond growers interested in volunteering their orchards (any age orchard works) for the research conducted by UC Davis plant pathologists, please contact Daisy Hernandez.

    Thank you all for your time and help.

    Contact:
    Daisy Hernandez, PhD, Student
    David Rizzo Lab,
    UC Davis
    Email: dahe@ucdavis.edu

  • Grazing & Riparian Restoration Are Compatible When You Put in the Work

    With a little time and effort, rangeland managers can have a dramatic impact on the resilience of California’s riparian areas, which are important to the state’s human, environmental and economic well-being. Rangeland ecologists at the University of California, Davis, found that when ranchers invest even one week a year in practices that keep cows away from creeks — like herding, fencing and providing supplemental nutrition and water — they can improve riparian health by as much as 53 percent.

    “The human factor is remarkably significant,” said Ken Tate, professor and Cooperative Extension specialist in the UC Davis Department of Plant Sciences. “Common thinking is that effectiveness of various rangeland management tools is site specific and largely due to site factors, such as topography and plant communities. Some practices are better suited to certain ranches for these reasons. But this study suggests that how you implement the tools might be the biggest factor in keeping rangelands productive and environmentally sustainable.”

    Tate collaborated with UC farm advisors and several other UC rangeland ecologists on the large-scale riparian conservation study recently reported in the Rangeland Journal.  

    One-third of California — 38 million acres — is rangeland. Much of it is mountainous and arid and managed for livestock production. Grazing on rangeland feeds livestock and also offers many environmental benefits like keeping invasive weeds in check, reducing risk and intensity of wildfires, and supporting habitat for certain animals and plants found nowhere else in the world.

    Problems arise, though, when cattle spend too much time near water, where manure can create water-quality risks for people downstream. That is especially true in California where some 80 percent of the state’s drinking and irrigation water is stored on or passes through rangeland. Overgrazing in riparian areas also tramples sensitive habitat and lets perfectly good forage on hillsides go to waste.

    Examining 1 million acres

    Tate and his team studied 46 grazing units on ranches and national forests covering nearly 1 million acres of dry, rugged rangeland in east-central and northeastern California. With the ranchers’ help, they looked at the relationship between number of livestock, managerial effort and riparian health. To measure riparian health, researchers looked for tiny aquatic bugs, animals and insects known as benthic macroinvertebrates.

    “We collected the kind of things you’d find under rocks when you crawled around creeks when you were a kid,” Tate explained. “The types of bugs and creepy crawlies present and absent tell us a lot about the biodiversity and health of a stream.”

    The team found no significant relationship between riparian health, number of livestock and simple yes/no answers on whether ranchers used fencing, herding or water and salt licks on hillsides to coax cattle from creeks. There was, however, a significant correlation between riparian health and time spent implementing those tools.

    “It doesn’t take a lot of effort, but it does take some effort,” Tate said. “When you put a salt lick on a hillside to attract cattle, for example, it’s going to lose its effectiveness if you don’t go back and refill it and move it to another hillside when the grass around it is grazed. Cows cannot live by salt alone.”

    Tate is encouraged by the results and the solutions they suggest.

    “We see a lot of win-wins,” Tate said. “Effective management opens up new forage opportunities and increases productivity. And when you have more useable land, you relieve pressure on riparian areas, which is good for the environment and for agriculture.” — By Diane Nelson, UC Davis

  • CA Dairy Organizations Host 900+ in Successful Virtual Summit

    Dairy Cares — California’s dairy farmers are leading change and making significant progress in reducing greenhouse gas (GHG) emissions and advancing planet-smart, sustainable farming practices. Ongoing partnerships remain critical to this progress. On November 5-6, the virtual California Dairy Sustainability Summit welcomed 900+ registrants, with more than 600 tuning in live throughout the two-day online event.

    The virtual summit hosted conversations among dairy farmers, industry leaders, government officials, leading researchers, technology providers, and sustainable food, consumer, and nutrition experts. The program recognized true sustainability includes economic and social considerations, in addition to environmental—ultimately aiming to ensure the ongoing availability of affordable, nutrient-rich foods. Given the current economic challenges, this effort is paramount as more than 54 million Americans currently face food insecurity. Through panel discussions and keynotes, speakers recognized accomplishments and opportunities to further improve the sustainability of family dairy farms and the entire supply chain.

    World-renowned researchers provided important perspective and scientific basis for discussing strategies and policies to drive change. Dr. Ermias Kebreab of the University of California, Davis shared research demonstrating significant reductions acheived in the water and GHG footprints of California dairy farm production. He noted that global GHG emissions could be reduced by 1.73% if all regions could produce milk as efficiently as California. Dr. Frank Mitloehner of UC Davis explained how methane has a relatively short atmospheric lifetime, and that the state’s efforts to reduce dairy methane can lead to global cooling. Dr. Myles Allen of the University of Oxford further highlighted the differences between methane and carbon dioxide and why they should be treated differently in strategies to reduce global warming.
     
    California’s state officials also contributed important insights. Richard Corey, Executive Officer of the California Air Resources Board explained how the state’s policies are helping to reduce GHGs, noting that incentive-based approaches funded through public-private partnership—such as the state’s dairy digester program—are critical to that effort. Carlos Suarez, California State Conservationist highlighted the great history and ongoing conservation efforts taking place through partnership between the USDA Natural Resource Conservation Service and dairy farmers—helping improve the protection of air quality, water resources, soil health, and wildlife habitat. Jenny Lester Moffitt, Undersecretary of the California Department of Food and Agriculture led a discussion among dairy farmers, as they shared their personal experiences with adopting new farming practices to improve soil health and water conservation.
     
    Leaders of the nation’s largest dairy cooperatives and the US Dairy Export Council also shared their visions for sustainability, focusing on employees (both on farms and within processing facilities), animal welfare, the environment, economic viability, and nutrition. The national dairy industry is committed to reducing GHGs, working toward a net zero climate impact by 2050. Leaders noted that strong partnerships and advancements in technology—as well as rural connectivity—will all be critical to achieving this goal.
     

    More than 50 speakers participated throughout the two-day virtual event—sharing unique insights on a wide variety topics. Sessions highlighted important efforts to improve the protection of environmental resources and further the adoption of renewable energy. Dairy farmers also discussed participating in community efforts to ensure clean drinking water for all, and working in partnership with researchers, technical experts, and government agencies to improve how groundwater resources are protected. Tremendous opportunities are currently being explored, including avenues for maximizing the use of manure nutrients on crops across California’s rich and diverse agricultural landscape.

    Despite economic challenges and uncertainty, speakers expressed optimism and an ongoing willingness to work together. “I think we’re just about to hit our stride,” said Lyle Schlyer, President of Calgren Dairy Fuels, a company that partners with dairy farmers to create renewable, carbon-negative transportation fuel. Schlyer participated in a panel discussion about opportunities and strategies to ensure dairy biogas continues to help fuel California’s clean energy and climate goals.
     
    Overall, the virtual California Dairy Sustainability Summit took a meaningful look at complex sustainability issues and the bigger picture. Digital consumer expert, Steve Lerch said that while consumers value sustainability, it’s difficult to fully understand, measure, and compare what brands and companies are doing to be sustainable. For this reason, it’s important to communicate a clear and compelling sustainability story. It was also noted that the ongoing global pandemic has further highlighted the importance of nutrition, as well as our overall health and well-being. Milk and dairy foods play an important role in nourishing people of all ages, to help create healthier communities in California and beyond.
     
    The California Dairy Sustainability Summit is hosted by Dairy Cares, California Dairy Research Foundation, California Milk Advisory Board, California Dairy Quality Assurance Program, and Dairy Council of California. The summit would not be possible without the generous support of its sponsors. Organizers look forward to future opportunities to host ongoing collaborative efforts.
    2020 has been a year of many challenges, but also of creativity, compassion, and perseverance. The Virtual California Dairy Sustainability Summit is an example of that spirit and a milestone in the ongoing efforts to advance planet-smart dairy farm practices.

  • Assessing the Costs & Benefits of Winter Cover Cropping in CA

    Winter cover cropping is a promising agricultural management practice that boosts soil health. This article discusses a benefit-cost analysis of winter cover crop adoption and introduces a web-based interactive calculator for farmers to assess changes to baseline farm profits.

    Winter cover cropping is an agricultural management practice that can enhance soil health while protecting fields from soil erosion and compaction. Cover crops are typically grown on farmland that would otherwise be left fallow in the wintertime, such as fields used for annual spring-summer crops, or in between rows of trees or vines, and thus do not replace a cash crop. Despite its well-known soil health and ecological benefits, and popularity in other parts of the U.S., winter cover crop adoption rates are low across California’s specialty crops. To better understand drivers and incentives for adoption, we created a benefit-cost calculator that estimates how baseline profits change as a farmer integrates winter cover cropping.

    This tool was designed for specialty-crop farmers who are interested in growing winter cover crops and want to understand how long it will take for that investment to break even. However, the tool is useful for anyone interested in better understanding the financial implications of cover cropping. In this article, we explain the methodology behind the tool and how to use it.

    Methodology

    We developed a calculator that estimates the expected changes in expenses and revenues associated with the introduction of winter cover cropping for a given farming operation. We started by modeling the implications of winter cover crops to average farms that grow processing tomatoes and almonds, two of California’s most important agricultural commodities. The model estimates a benefit-cost ratio in present value terms, i.e., the ratio of the sum of benefits over the sum of costs accumulated over time and discounted to the present.

    In our baseline analysis, we considered cover crop seed mixes that are commonly used for winter cover cropping in California’s Central Valley. For tomato operations, this was assumed to be a small grain forage mix (e.g., bell beans, winter peas, common vetch) and for almonds, this was assumed to be a more expensive clover mix.

    Table 1 lists potential benefits and costs of winter cover cropping. Benefits and costs are not the same every year. The monetary values for each of these components are incorporated into the model at the specific time when that benefit or cost is likely to be experienced.

    Benefits include increased income from greater yields, which results from improvements in soil quality, fertility, and soil-water relations due to cover cropping. Benefits also include reductions in expenses associated with soil erosion control, nutrient cycling, weed control, mycorrhizal fungi colonization, and reduced tillage operations. Almond growers may also benefit from lower beehive prices.

    The potential for cover crops to affect the irrigation requirements of cash crops is debated in the scientific literature. Cover crops may lead to higher water infiltration (resulting from improved porosity of the top soil), which can lead to increased capture of winter and spring rainfall, increased soil-water storage, which in turn can delay irrigation start and eventually reduce spring/summer irrigation requirements slightly; however, these effects are soil-specific and difficult to quantify and generalize and, thus, are not included in the baseline model. Other potentially valuable aspects of cover cropping that were not explicitly accounted for in the analysis include reduced soil sealing and compaction, better soil oxygen concentration and diffusion rates, as well as increased effectiveness of salt-leaching practices.

    Furthermore, while cover cropping has been shown to improve ecosystem services and downstream user benefits, these are not included in the baseline benefit-cost calculations. These societal benefits, which include increased soil organic matter, the protection of downstream surface water quality via reduced runoff, and carbon sequestration through enhanced soil-carbon storage, were not included because they would not accrue as a revenue flow to the farmer choosing to adopt.

    Costs include the initial expenses associated with cover crop seeds, planting, and termination, depreciation of machinery used for this management practice, and time spent learning how to incorporate cover crops into an operation, as well as disseminating new instructions to crewmembers. The model accounts for financial losses due to potential harvest complications with cash crops. For example, a heavy rain at the end of March could delay termination of cover crops, and thus delay the planting of tomato seedlings, which can postpone the timing of tomato harvest. This poses a potential complication for farmers who contract with tomato canneries, resulting in penalties.

    To quantify these benefits and costs, we collected data from UC Ag Issues Center’s Cost and Return Studies, scientific publications, semi-structured farmer interviews, and field experiments to establish an average value of each benefit and cost component. We then aggregated these components to estimate benefit-cost ratios for tomato and almond production systems, where a value of the ratio greater than 1 indicates a net positive change in profits. The interactive calculator is seeded with the average value for each benefit and cost component, but can be adjusted by the user to reflect a specific farming operation. While our model attempts to be as comprehensive as possible, some potential benefits or costs are not included, such as interactions with pruning or other practices.

    Results

    When using average values for all the benefit and cost components, we find that almond systems have a benefit-cost ratio greater than 1 when considering a 30-year time horizon, meaning that benefits are likely to exceed costs on average. When using average values for the tomato system, we find the benefit-cost ratio to be less than 1, given their assumed 10-year time horizon. The time horizons of 10 and 30 years were chosen for tomato and almond operations, respectively, to reflect typical rotation patterns and crop life cycles. Figure 1 displays these results year-over-year. At the 10-year mark for tomatoes and the 30-year mark for almonds, the average benefit-cost ratios are 0.5 and 1.3, respectively, indicating that total benefits eventually outweigh total costs for almond operations, but not tomatoes.

    Winter cover cropping is an investment in the long-term viability of agricultural operations. The benefits and costs accrue differently over time and may vary from year to year. Harvest complications with a cash crop reduce profitability but can be avoided with flexible contractual obligations or by growing a cover crop with predictable senescence. Overall, our results show the value of this soil management practice is greatest for California farmers with a longer time horizon and willingness to manage a cover crop as carefully as their cash crop.

    Interactive Web-based Calculator

    The web-based cover crop calculator, partially shown in Figure 2 and available here, is an interactive decision-support tool that calculates the benefits and costs of winter cover cropping in almond and processing tomato operations. The tool estimates how much farmers can expect their profits to change after growing winter cover crops for a certain number of years. All values used in the calculator are flexible and can be adjusted to match the reality on any commercial farm. The calculator is seeded with the average values for each cost and benefit component that we considered, but the user can easily adjust or remove any component.

    The calculator assumes continuous cover cropping after the year of adoption (first year), and that all benefits of cover crops begin accruing within the first five years. Importantly, the tool may not capture every potential benefit and cost from introducing cover crops into a farming operation. It simply serves as a guide to when a farm can expect to experience economic returns, based on the monetized benefits and costs.

    As mentioned previously, cover crops could either increase or decrease spring-summer irrigation requirements. Although this component is not included in the baseline net present value model, the calculator is flexible in this variable. The user can specify the extent to which cover crops increase or decrease irrigation requirements in the growing season and can add irrigation costs to germinate the crop if needed, and then observe how their baseline profits shift accordingly. Users can also explore how a financial incentive, in the form of an annual subsidy payment per acre of cover-cropped farmland, will affect their outcomes. The calculator allows one to value the social benefits of cover cropping (ecosystem services, carbon sequestration, and downstream water quality) via this subsidy component. – By Ellen Bruno, Alyssa DeVincentis, Samuel Sandoval Solis, and Daniele Zaccaria, UC Giannini Foundation of Agricultural Economics, University of California

    Authors’ Bios

    Ellen Bruno is an assistant Cooperative Extension specialist in the ARE department at UC Berkeley. Alyssa DeVincentis is a Ph.D graduate from UC Davis in Hydrologic Sciences. Samuel Sandoval Solis is an associate professor and Cooperative Extension specialist and Daniele Zaccaria is an associate Cooperative Extension specialist, both in the Department of Land, Air and Water Resources at UC Davis. They can be reached at ebruno@berkeley.edu, ajdevincentis@ucdavis.edu, samsandoval@ucdavis.edu, and dzaccaria@ucdavis.edu, respectively. 

  • Grower Survey to Address Future Innovations in Weed Management

    Weeds can be a significant problem in berries, tree fruits, tree nuts, and vine crops (e.g. grapes, hops, etc.) especially after transplanting and during flowering and fruit and nut set. Herbicides are a primary tool for managing weeds, even though the evolution of herbicide resistance has limited the utility of many products and off-target movement can sometimes result in damage to trunks, shoots, leaves and flowers. Many growers are transitioning to organic systems to address changes in consumer preferences or satisfy the requirements set in place to enter export markets.

    Perennial cropping systems are exploring technologies such as automated harvesters and pruners, to reduce labor demands, and canopy sensing sprayers, to minimize the amounts of crop protection chemicals applied to shrubs, trees, and vines. Novel weed control tools that eliminate or reduce the need for herbicides are actively being developed for and marketed in the agriculture and horticulture industries. These new technologies could begin to play and increasingly large role in future crop production, particularly in high-value specialty crops that 1) have limited herbicide options, 2) are sensitive to herbicide injury, and 3) are heavily reliant on a labor market that is simultaneously growing more scarce and more expensive.

    A team of weed scientists from UC Davis, Oregon State University, and Cornell are asking berry, tree fruit, tree nut, and vine crop growers to take 5 to 10 minutes and answer this short and anonymous survey (link below) about your current weed management practices and your interest in novel technologies, like vision-guided sprayers and cultivators, and electric, steam, and pressurized water weeders. This will help us plan research and extension projects that will address stakeholder concerns regarding the future of weed management.

    There’s always a chance that we forgot to include some amazing tools that are emerging on the horizon; please feel free to e-mail Lynn Sosnoskie at lms438@cornell.edu and let her know what you think the future of weed control will look like.

    Thanks for your time. We appreciate your support of weed science research.

    Survey link: https://cornell.ca1.qualtrics.com/jfe/form/SV_bEpfAijoP7puQDP

  • UC ANR Study Outlines Costs & Returns of Producing Lemons in Southern CA

    A new study on the costs and returns of establishing and producing lemons in Ventura County has been released by UC Cooperative Extension in Southern California and UC Agricultural Issues Center, both part of UC Agriculture and Natural Resources.

    “Coastal agriculture is always in transition and as strawberries and vegetables become less profitable due to markets and labor availability, lemons have returned as a potentially profitable alternative to those crops,” saidBen Faber, UC Cooperative Extension farm advisor for Ventura County and coauthor of the study.

    California lemon acreage was at roughly 47,000 acres in 2018-19, of which Ventura County accounts for 31%, according to the 2019 Ventura County Crop Report. Ventura County was growing lemons on 14,407 acres in 2019.

    “The profitability of lemon production depends on the price of land,” said Etaferahu Takele, UC Cooperative Extension farm management advisor for Southern California, another coauthor of the study. “If the price of land continues in its current trend, it could be prohibitive for new entrants to make a profit and limit further expansion of lemon production in the county.”

    Their cost analysis describes production operations for Eureka lemons on macrophylla rootstock, which are planted at 155 trees per acre with an expected life span of 40 years.

    The study includes a detailed summary of costs and returns and a profitability analysis of gross margin, economic profit and a break-even ranging analysis table, which shows profits over a range of prices and yields.

    Input and reviews were provided by Ventura County farm advisor and grower cooperators. The authors describe the assumptions used to identify current costs for lemon establishment and production, material inputs, cash and non-cash overhead.

    The new study, “2020 – Sample Costs to Establish and Produce Eureka Lemons in Ventura County,” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website at http://coststudies.ucdavis.edu and the UCCE Riverside County Farm Management website at https://ucanr.edu/sites/Farm_Management/files/338947.pdf. Sample cost of production studies for many other commodities are also available on the websites.

    For additional information or an explanation of the calculations used in the studies, refer to the section of the report titled “Assumptions” or contact Takele at (951) 683-6491 Ext. 243 ettakele@ucanr.edu or Donald Stewart at the UC Agricultural Issues Center at (530) 752-4651, destewart@ucdavis.edu.

    For information about production of lemons in Ventura County, contact Faber at bafaber@ucanr.edu. — By Pamela Kan-Rice, UCANR

  • Walnut Replanting Considerations in a Lean Price Year

    When prices are lean walnut farming is tough business. Farm advisors are not economists or financial advisors. However, farm advisors can be useful in providing best practices for economically sustainable production. Two key economic decisions growers face are when to replant individual trees and when to remove and replant entire orchards.

    Learn from Dying Trees to Improve Management of the Whole Orchard:

    Former Advisor Carolyn DeBuse, and Emeritus Advisor Bill Krueger wrote about the need to pause before replanting, by asking why the tree died in the first place. Saturated soils and soil borne pathogens are common culprits for tree loss. It is important to carefully evaluate recently declining trees, particularly evaluating their root systems for a possible cause. Your pest control advisor or local farm advisor can help with this diagnosis. Can changes be made to reduce the chance of additional trees declining and increase the chance of success for replanted trees? For Phytophthora and nematodes, these changes are often genetic (i.e. replant rootstock selection) but may also include a chemical approach. However, the needed action is just as often cultural, whether it is adjusting irrigation set time to prevent ponding or installing stream-splitters to keep water off trunks.

    Water logging is a common cause of walnut tree decline: sacvalleyorchards.com/blog/walnuts- blog/yellowing-collapsing-walnut-trees-pt-1-water-logging. The Howard variety appears particularly sensitive to saturated soils: sacvalleyorchards.com/blog/walnuts-blog/yellowing-collapsing-walnut-trees- pt-2-yellowing-howard-problem. In addition to tracking saturated conditions with soil moisture monitoring, a key practice to not over-watering is irrigating only when demanded by the trees, as indicated through regular pressure chamber use. Learn more at: sacvalleyorchards.com/manuals/stem-water- potential.

    Tree Replanting Decisions:

    When a tree dies and is removed, there is always a question of whether to replant in that spot. The decision of whether to replant an individual tree is a gamble that the replant will become established and produce enough to offset its associated costs by the end of the orchard’s life. A decision that is an automatic “yes” early in the orchard’s life becomes more complicated as the orchard ages.

    The shading from surrounding trees, and the ensuing low probability of successful vigorous growth weighs against the desire to replant and establish lost production. DeBuse and Krueger noted that if the orchard floor has over 75% shade at midday, the chance of a successful replant is slim. However, UC Davis Walnut Specialist Bruce Lampinen believes that a successful replant is dubious in orchards with over 60% shading. If the decision to replant has been automatic for you, pause to consider the cost of an unsuccessful replant and first evaluate how much light is available to the new tree.

    After weighing the success of the replant and evaluating why the original tree died, if you do replant, follow the best practices to help nurture this investment. Root removal, possible spot fumigation, nursery product selection, and correct planting are the key steps. Of these, nursery product selection is a particularly critical step, if possible, tailor the choice of rootstock to the main source of tree loss (see rootstock table below). As part of nursery selection, choosing a bareroot over a potted tree is typically ideal because you are starting with a tree that is larger and easier to manage. Once the replant is in place, the tree stands little success without paying extra attention to the need to modify irrigation and fertilization. You can learn more in the excellent guide by DeBuse and Krueger at: sacvalleyorchards.com/walnuts/orchard-development/replanting-individual-trees.

    Orchard Replanting Decisions:

    In addition to a lack of available light, general orchard decline is a second major reason to rethink replanting individual trees. General orchard decline in old age, frequently the result of weak trees facing an onslaught of multiple pests and diseases (figure 1), means replants make little sense because of the short window remaining in the orchard’s life. Instead, the orchard should continue to be farmed without replants until it is no longer economically feasible to do so.

    Figure 1. An orchard facing general decline, with a high rate of tree loss. Extensive crown gall, trunk cankers, and high nematode counts all present in this orchard.

    Amidst lean prices, if this is the year that you slate an orchard for removal, there are several steps you should consider before removal. A critical initial step, just as with replanting individual missing trees, is to ask why the orchard is in decline, and if those problems may follow you into the next planting. In addition to assessing the risk of the replant problem, and the persistence of crown gall, a nematode sample taken while the current trees are still in the ground is a great start. You can learn more about nematode sampling at: growingthevalleypodcast.com/podcastfeed/2019/10/22/nem-sampling and result interpretation and the next steps for replanting amidst high lesion nematode counts at: sacvalleyorchards.com/walnuts/orchard- development/replanting-into-nematode-infested-soils.

    Building upon this initial diagnosis step, consider the following steps:

    1. Assess potential carry-over problems before harvest.

    2. Kill the roots of the old orchard. The established best practice for this is cutting down trees above ground during October and within 5 minutes painting the stump with Garlon3A, or a mixture of 1:3 mixture of Garlon3A and MorAct.

    3. Wait a full growing season before replanting walnuts. This is the step where there are a range of management choices, such as the decision to fumigate, the use of a spring-summer crop to dry down deep soil moisture, or even exploration of a new technique like anaerobic soil disinfestation.

      This is also the step, where you could consider whole orchard recycling (WOR), whereby the previous trees are chipped and incorporated back into the soil. In almonds, this has been successful both for the performance of the subsequent planting and for soil health. Problems and success with WOR in walnut have yet to be demonstrated, with only a single pilot demonstration of young second generation WOR trees to- date. Until we have data on the persistence of crown gall and lesion nematode in roots of a recycled orchard, this practice is not advised for orchards with heavy cases of these afflictions. You can learn more about WOR at orchardrecycling.ucdavis.edu. WOR is an expensive practice, however the practice is now recognized for potential financial support through the CDFA’s Healthy Soils Program: cdfa.ca.gov/oefi/healthysoils.

      1. Fumigate, if necessary. The choice of whether to fumigate is centered around the concerns of root lesion nematodes, the replant problem, and to a lesser extent crown gall when replanting walnut orchards. Specifically, if lesion nematode is present in the old orchard, nematicide (e.g. Telone) fumigation, in addition to all the other steps may be necessary to have a successful replant to walnut. Fumigation is expensive, however the carryover problems from the previous orchard can prove far more costly. Cost savings with fumigation can be achieved by opting for strip fumigation specifically mapped for the tree rows, instead of broadcast fumigation. Adequate fumigant distribution can be problematic especially on clay-type soils. To ensure a successful fumigation, it is critical to dry down the soil to 12% moisture for optimal fumigant efficacy.

      2. Replant on an appropriate rootstock. Consider the potential benefits of clonal Paradox rootstocks, particularly against nematodes (VX211) and Phytophthora (RX1). See detailed rootstock traits in the table below.

      Find more about orchard removal and replant steps at: sacvalleyorchards.com/walnuts/diseases/considerations-for-replanting-walnut-orchards. Finally, if you are removing and planting a new walnut orchard, a key document to have on hand when financially planning is the Sacramento Valley UC Walnut Cost Study, which can be found at: coststudies.ucdavis.edu/en/current/commodity/walnuts.

      Article By:

      -Luke Milliron, UCCE Orchards Advisor Butte, Glenn & Tehama Counties

      -Katherine Jarvis-Shean, Orchards Advisor Yolo, Solano & Sacramento Counties