Posts Tagged: agriculture
Organic strawberry yields boosted by technique refined through UCCE research
Anaerobic soil disinfestation helps suppress weeds, disease without fumigants
Troubled by puny plants, low yields and persistent mite problems, third-generation Southern California strawberry grower Glen Hasegawa was ready to give up on his transition from conventional to organic 12 years ago.
“I've always liked a challenge – but it turned out to be more of a challenge than I thought it would be!” he said.
But then, with the help of scientists including Oleg Daugovish, UC Cooperative Extension strawberry and vegetable crop advisor in Ventura County, Hasegawa tried a technique called anaerobic soil disinfestation (ASD). When applied correctly, the multi-step ASD process creates a soil environment that suppresses pathogens and weeds and makes for healthier, more robust crop growth.
“Back in the day, it was really hard to get the plant growing vigorously in organic,” said Hasegawa, owner of Faria Farms in Oxnard. “So we started using the ASD and then you could definitely see that the plant had more vigor and you could grow a bigger, better plant using it.”
Seeing that he could produce yields “in the neighborhood” of those grown in conventional strawberry fields fumigated with synthetic fumigants, Hasegawa was able to expand his original 10 acres of organic strawberries to 50 acres.
“I guess you could say I'm kind of a convert,” he said, noting that he now applies ASD to all his acreage each year in late spring.
Joji Muramoto, UC Cooperative Extension specialist in organic production based at UC Santa Cruz, has been experimenting with ASD since it was first brought to the U.S. from the Netherlands and Japan in the early 2000s. Carol Shennan, a professor in the Department of Environmental Studies at UCSC, and Muramoto were among the first to try the technique in California. They found that ASD successfully controlled an outbreak of Verticillium wilt – caused by the pathogen Verticillium dahliae – at UCSC's small organic farm in 2002.
Since then, Shennan, Muramoto, Daugovish and their colleagues have seen encouraging results at 10 trial sites across the state.
“We demonstrated that ASD can provide comparable yields with fumigants, in side-by-side replicated trials,” Muramoto said.
ASD promotes host of beneficial changes to soil ecosystem
ASD comprises three basic steps: incorporating a carbon source that is easily digestible by microbes in the soil (traditionally, rice bran has been used), further encouraging fermentation by covering the soil with plastic to limit oxygen supply, and finally adding water through drip irrigation to initiate the “anaerobic” decomposition of the carbon source and maintain the three-week “cooking” process.
The resulting cascade of chemical, microbiological and physical changes to the soil creates an ecosystem that is both conducive to strawberry growth – and inhospitable to pathogens and weeds.
“It's not like a pesticide where you have a mode of action, and thus resulting in ‘A' and ‘B' for you,” Daugovish explained. “There's a sort of cocktail of events that happens in the soil; they all happen interconnectedly.”
Compared to similar fields that did not undergo the process, ASD-applied organic strawberry fields across California have seen yields increase by 60% to 70% – and even doubling in some cases, according to Daugovish.
The UCCE advisor also shared the story of a longtime grower in Ventura County, who came to him with fields in “miserable” condition; they were plagued by one of the world's worst weeds, yellow nutsedge, and infected with charcoal rot, a disease caused by the fungus Macrophomina phaseolina. But after applying rice bran and following the ASD recipe, the grower saw phenomenal results.
“The only complaint he said to me was, ‘Now I have too many berries – we have to have more pickers to pick the berries!'” Daugovish recalled.
Via researchers' meetings, online resources, on-farm demonstration trials and word of mouth from peers, use of ASD by California strawberry growers has grown significantly during the past two decades. Tracking the purchase of rice bran, Muramoto estimated that about 2,500 acres were treated by the ASD-related practices in 2023 – covering roughly half of the 5,200 total acres of organic strawberries in California.
Muramoto directly links the growth of California organic strawberry production – which now comprises about 13% of total strawberry acreage in the state – with the increasing adoption of ASD.
“If you remove the acreage with the applied rice bran over the last 10 years or so, organic strawberry acreage is just flat,” he said.
Within the last decade, acreage of organic strawberries with ASD-related practices increased by 1,640 acres, which is a boon for air quality, human health and long-term soil vitality. According to Muramoto's calculations, that increase in organic acreage translates to a reduction of about 465,000 pounds of fumigant active ingredients that would have been used in growing conventional strawberries.
“There are hundreds of reports of acute illnesses related to fumigation in the record, so it's very important to find alternatives to fumigants,” said Muramoto, citing California Department of Pesticide Regulation documents.
Research continues to make ASD more economical, effective
The popularity of ASD has come at a price, however, for organic strawberry growers.
“There's more organic out there, and I think most of the organic guys are using it, so there's more demand on the rice bran; the price has been steadily going up every year, like everything else,” said Hasegawa, adding that he has been trying to decrease the amount of carbon while maintaining ASD's efficacy.
On top of greater demand from other growers and from beef cattle and dairy producers (who use rice bran as feed), the price also has increased due to higher costs in transporting the material across the state from the Sacramento Valley. So Daugovish and his colleagues – including Peter Henry, a U.S. Department of Agriculture plant pathologist – have been searching for a cheaper alternative.
“We all want an inexpensive, locally available, reliable, easy to use and functional carbon source, which sounds like a big wish list,” Daugovish said.
Carbon sources such as bark, wood chips, or compost are ineffective, as the crucial ASD microorganisms are choosy about their food.
“Microbes are just like cows; you can't feed them straight wood; they get pretty angry,” Daugovish explained. “And if you feed them something with too much nitrogen, they can't digest it – they get the runs. Microbes are the same way – you have to have the right proportion of stuff so they feel comfortable doing what they're doing.”
In search of an ideal replacement, researchers tried and ruled out grass clippings, onion waste, glycerin and coffee grounds. Finally, they pivoted to a material with properties very similar to rice bran: wheat bran, in the form of wheat middlings (also called midds, a byproduct of flour milling) and dried distillers' grain (DDG, a byproduct of ethanol extraction).
After field experiments in Santa Paula, the UC and USDA researchers found that midds and DDG were just as effective at controlling soilborne pathogens and weeds as rice brain – but at 25% to 30% less cost. Their results were published last year in the journal Agronomy.
“Not surprisingly, the wheat bran has worked almost exactly the same as rice bran,” Daugovish said.
He and Muramoto are now conducting trials with wheat bran at commercial fields, and the initial results are promising. Daugovish said the grower at one site in Ventura County has seen a 90% reduction in Macrophomina phaseolina, the causal pathogen of charcoal rot, in the soil – and an 80% to 90% drop in yellow nutsedge germination. They are waiting for final yield numbers after the coming summer.
While ASD has been beneficial to organic productivity and soil health, both Daugovish and Muramoto acknowledged specific limitations in suppressing the “big three” strawberry diseases: Verticillium wilt, Fusarium wilt and charcoal rot. In coastal areas with cooler soil temperatures, for example, ASD can actually exacerbate the latter two diseases, as the fungal pathogens feed on the rice bran.
“We know it works at warmer temperatures, but, practically, it's hard to do in coastal California,” Muramoto said. “It would be nice if we can find a way to suppress Fusarium wilt at a lower temperature, but we don't have it right now.”
That's why researchers emphasize that ASD is not a “silver bullet.” It's just one tool in the organic toolbox, which includes careful crop rotation, disease-resistant strawberry varieties and better diagnostic tests that help growers pinpoint outbreaks and make the application of various methods more targeted and more efficient.
And scientists will continue to optimize ASD to make it more effective and economical for growers in the different strawberry regions of California – from the Central Coast to the Oxnard Plain.
“We know it can work really well; it's just finding the most sustainable way to do this in our region,” Daugovish said. “We've got to just have an open mind and keep trying.”
/h3>/h3>/h3>REC System Director Haver encourages systemic approach to agriculture
Agriculture generates $59 billion and employs nearly 400,000 individuals in California. The industry, however, is often threatened by challenges like climate change, land conversion and water scarcity. Motivated to act, Sustain Southern California – an organization associated with UC Irvine Beall Applied Innovation – hosted a roundtable discussion on Feb. 20 featuring subject matter experts including Darren Haver, director of UC Agriculture and Natural Resources' Research and Extension Center System.
During his keynote address, Jose Arriaga, Orange County Agricultural Commissioner, defined sustainability as food and fiber production that does not compromise the ability for future generations to meet their needs. In doing so, he acknowledged the benefit of discussing such timely topics with key players, especially for places where agriculture is not as prevalent as it used to be.
“Many people don't think of Orange County as a place for agriculture. It's probably because less land is being reserved for agriculture, not like back in the day. And that worries me,” said Arriaga.
The first roundtable discussion centered on sustainable agriculture, with Haver participating alongside other industry leaders based in Southern California, including A.G. Kawamura of Orange County Produce, Steve Brazeel of Sunterra Produce and Elevated Foods, Anthony Curci of Buttonwood Ranch and Parker Cohn from Performance Resource Management.
In discussing today's generation, Haver said that he has seen a shift over the last few decades away from yield alone, which used to be the most important aspect of production in agriculture. Today, much more attention is dedicated to sustainability – a change that Haver attributes to the younger generation of researchers and plant scientists working in agriculture.
There has also been an emphasis on sustaining the environment while maintaining economic progress. Haver recognized these important elements, but highlighted the social impact of sustainability, too.
“I don't have all the answers, but I do believe that addressing the environmental, economic and social aspects of agriculture is important. I also think that these factors should be addressed systemically rather than in silos,” said Haver.
Southern California agricultural producers, in particular, are responsible for $7.8 billion in gross receipts and nearly 100,000 jobs directly related to agriculture. In Orange County alone, where Haver is based at the South Coast Research and Extension Center, agriculture makes up $86 million of total economic output, with nurseries leading as a top commodity followed by fruit trees, vegetable production and livestock and apiary.
Climate-smart crop production workshops March 5-7 in Ventura, Salinas and Tulare
Growers invited to learn how to manage risks to fruit, nut, vegetable production
UC Cooperative Extension is offering workshops in Ventura, Salinas and Tulare to help growers adapt their fruit, nut and vegetable production practices to variable climate conditions.
"Growers, farm and ranch managers, and technical assistance providers can learn about the latest research and advances in managing risks to agricultural production that can result from climate change and climate variability,” said Daniele Zaccaria, associate professor in agricultural water management for Cooperative Extension at UC Davis.
Tapan Pathak, UCCE specialist at UC Merced, will speak about climate change trends, potential impacts on agricultural production and decision support tools. Zaccaria and local experts will discuss cover cropping, pests and other issues.
During a roundtable session, participants will discuss their own production challenges resulting from climate change and variability.
“Participants will also learn about tools available to aid manage climate change and climate variability risks," Zaccaria said.
The Climate-Smart Agricultural Production Practices workshops will be held in three locations:
Ventura: Vegetable and Berry Production
March 5 (8 a.m.–1:30 p.m.)
669 County Square Dr., Suite 100
Speakers include UCCE advisors Andre Biscaro, Ben Faber and Mark Battany, and other scientists and experts from Ventura County Resource Conservation District and Land IQ. Register at https://bit.ly/VenturaCrops.
Salinas: Vegetable, Berry and Grapevine Production
March 6 (8 a.m. –2 p.m.)
1432 Abbott St.
Speakers include Daniel Hasegawa and Eric Brennan of USDA-ARS and UCCE advisors Larry Bettiga, Michael Cahn and Mark Bolda. Register at https://bit.ly/SalinasCrops.
Tulare: Fruit and Nut Production
March 7 (8 a.m.–2 p.m.)
4500 South Laspina St.
Speakers include UCCE advisors Jhalendra Rijal, Mark Battany, Mohammad Yaghmour, Sandipa Gautam, Brent Holtz and other scientists and experts from USDA-NRCS, Almond Board of California; California Pistachio Research Board and Land IQ. Register at https://bit.ly/TulareCrops.
Workshops are free and include coffee breaks, lunch, workshop materials along with the presentations. Registration is required.
These workshops are supported by grants from the California Department of Food and Agriculture and USDA's National Institute of Food and Agriculture.
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Productores de almendras en alerta ante posible brote de patógeno
El invierno húmedo y El Niño crean condiciones favorables para una infección con el patógeno Phytophthora aéreo
Antes los pronósticos de lluvias torrenciales en California, expertos de Extensión Cooperativa de la Universidad de California (UCCE, por sus siglas en inglés) alertan a los productores de almendras sobre la posible presencia del patógeno Phytophthora aéreo, que se reproduce en condiciones húmedas y puede causar un daño severo a sus huertos.
El Phytophthora, un microorganismo infeccioso del suelo, apodado “moldes de agua” por su dependencia al agua, típicamente causa que la raíz y corona en la base de los árboles se pudran. Pero algunos Phytophthora aéreos pueden viajar hacia arriba e infectar partes más altas de los árboles. Una especie –Phytophthora syringae- está llamando especial atención debido al brote sin precedentes en el pasado invierno, estimulado por los ríos atmosféricos que azotaron a California.
“Fue encontrado interestatalmente -lo que significa que en cada condado productor de almendras- y con incidencia en huertos de entre 10 y 75 por ciento de árboles infectados, manifestó Florent Trouillas, especialista en patología de frutas y nueces de UCCE. Trouillas es además patólogo de plantas de UC Davis y su laboratorio está basado en el Centro Kearny de Investigación Agrícola y Extensión en Parlier.
Trouillas y sus colegas, Alejandro Hernández, estudiante de postgrado en UC Davis y Jim Adaskaveg, profesor de patología en plantas de UC Riverside, recientemente publicaron un detallado artículo en línea, describiendo el patógeno, el cual puede infectar una variedad de cosechas, pero en California impacta principalmente a los almendros.
Aunque no mata el árbol completo, la enfermedad seca las ramas, lo cual requiere mucho trabajo adicional y más gastos para los productores de almendra. En el 2022, las almendras fueron el cuarto producto más valorado en el estado, con ventas de hasta 3,520 millones de dólares.
Durante el brote de Phytophthora aérea del año pasado, los investigadores también observaron un nuevo y preocupante fenómeno: el P. syringae, históricamente conocido por atacar los cortes causados por podas, estaba directamente infectando los retoños nuevos en los almendros, sin heridas presentes.
“En realidad, esta fue la primera vez que observamos evidencia dispersada de infección en ramitas nuevas”, mencionó Trouillas.
Aunque generalmente raro, los brotes de P. syringae han sido tradicionalmente asociados con años húmedos de El Niño, de acuerdo con Trouillas –y las recientes y persistentes lluvias a lo largo del estado debe tener a los agricultores en alto grado de alerta.
Podar durante clima seco, monitorear y mitigar si es necesario
Mientras los agricultores tienden a podar durante temporada baja de invierno, deben estar alertas sobre los pronósticos del tiempo y buscar ventanas de 10 a 14 días de clima seco para llevar a cabo esas tareas, ya sea en la formación de árboles jóvenes o dando mantenimiento a los ya establecidos.
“Si los agricultores fueran a podar durante época de lluvias –antes o inmediatamente después- esto incrementa la posibilidad de infección ya que este patógeno se esparce guiado por el agua”, explicó Trouillas.
Los investigadores especulan que el P. syringae, normalmente se encuentra en el suelo, se transporta a las partes altas del árbol mediante fuertes vientos y lluvias torrenciales. Alternativamente, los procesos de cosechas como la sacudida y barrida, también producen movimientos de aire que pueden esparcir los microorganismos a las copas de los árboles, donde permanecen en espera de condiciones húmedas favorables. Los patógenos entonces atacan las heridas o las ramas tiernas, produciendo los característicos cancros y gomas.
Los patrones y colores de las bolas de goma son clave para el diagnóstico de la infección de este particular Phytophthora aéreo. Empezando alrededor de la época de floración (mediados de febrero), los agricultores deben monitorear los cortes causados por la poda, brotes y ramas jóvenes en los árboles, especialmente en la parte de la corona, buscando señales de la enfermedad.
La singular coloración de las bolas de goma - desde dorado y ámbar y purpureo obscuro a rojo brillante (ver fotos) – son clave para diagnosticar una infección de esta particular P. syringae. Pero se les urge a los agricultores a contactar al asesor local de Extensión Cooperativa para su confirmación.
“Es muy importante para los agricultores que cuando vean goma, no asuman que es phytophthora aérea, pues existen muchas otras enfermedades que pueden producir goma en los árboles”, expresó Touillas.
Si el diagnóstico es confirmado, el agricultor podrá aplicar un compuesto que puede mitigar la infección. El informe reciente de patólogos describe varios tratamientos opcionales curativos, así como medidas preventivas que reducen la cantidad del patógeno en el suelo y por tanto la posibilidad de infección.
Para más información sobre la historia y biología del patógeno, así como varias opciones para el manejo de la enfermedad, lea el artículo de Sacramento Valley Orchard. Fuente:https://www.sacvalleyorchards.com/almonds/trunk-soil-diseases/aerial-phytophthora-outbreaks-in-wet-years.
Adaptado al español por Leticia Irigoyen del artículo en inglés. Editado para su publicación por Diana Cervantes
Chicken community ‘coop-eration’ needed to test UC poultry health app
If you raise backyard chickens or breed game fowl, UC Cooperative Extension has an app for you. The new mobile app offers information for raising healthy chickens.
To test the usefulness of the UC Community Chicken app to people raising chickens, the Poultry Lab at the UC Davis School of Veterinary Medicine will pay poultry owners to participate in a two-week study with a follow-up survey three months later.
“Our study focuses on the development and evaluation of a new mobile app for backyard chicken owners and game fowl breeders,” said Maurice Pitesky, UC Davis School of Veterinary Medicine associate professor of Cooperative Extension. “The goal is to examine the app's effectiveness as a communication tool within the poultry community.”
To be eligible, participants must be backyard chicken owners who are 13 years or older or game fowl breeders over 18 years of age. They will need to have Apple or Android phones or tablets to access the app.
What's in the app?
The UC Community Chicken app contains six educational modules with short videos that cover health assessment, nutrition, vaccination, biosecurity, bird behavior and husbandry. It also features chat and feedback buttons so participants can communicate with the UC experts and other poultry owners.
“We value the thoughts and experiences of people who are raising poultry,” said Myrna Cadena, Ph.D. student in Pitesky's lab. “Their input will be valuable in shaping the way we extend information about poultry health.”
Study timeline
For two weeks, participants will explore the educational resources and other features and complete the surveys. Three months later, the researchers will follow up with a survey to assess the chicken owners' progress.
Participants who complete the entire study and follow-up survey will receive a $25 Amazon gift card via email. Those who do not finish the entire study will be compensated based on their level of participation. The study will be limited to 220 participants.
To register for the study, go to https://bit.ly/UCchickenapp. Once the study is ready, participants will be notified via email. The UC Community Chicken app will be available to the public after the study is complete. For more information about the study, contact Maurice Pitesky at drcluck@ucdavis.edu.