Posts Tagged: organic
Electric weed control research updates
From the eOrganic and Performance and Economics of Electric Weed Control in Organic Perennial...
Electrical weed control in organic blueberry - Oregon State cooperators
Several of us are part of a multi-state project on electrical weed control in organic blueberry and...
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>Protect Yourself from Pesticides
If you've used disinfecting wipes to clean surfaces in your home, an herbicide to control weeds in...
Practical Training of Nitrogen Planning and Management in Organic Production of Annual Crops
Habrá traducción al Español!
Where: This is an online virtual event
Monday November 27, 1-3 pm Session 1 Understanding nitrogen and soil organic matter
Monday, December 4, 1-3 pm Session 2 Compost, fertilizers and cover crops
Monday December 11 , 1-3 pm Session 3 Water, synchronizing demand and supply
Monday December 18, 1-3 pm Open house, Grower panel
Note: Limited to 80 participants -- Must enroll in all 3 classes (Session 1-3)
Cost $25 No one will be turned away due to lack of funds. Please email Rob Straser with questions (rkstraser@ucanr.edu).
Earn 6 hours of CDFA-INMTP continuing education credits (formerly CURES CE Credits)
Earn 6 hours CCA credits
About this workshop
In this 3-part series, participants will learn how to estimate nitrogen release from diverse organic sources and translate that knowledge to nitrogen fertilization plans and regulatory reporting requirements. In session 2 and 4, participants will be able to work on and receive feedback on their own nitrogen budgets. Over the first 3 sessions, we will cover the most common sources of nitrogen and complete a nitrogen budget.
Who should enroll?
Growers, CCAs, PCAs and other agricultural professionals who are interested in learning about nitrogen management in organic production are encouraged to enroll.
November 27, 2023, 1-3 pm Part 1: Understanding nitrogen: the nutrient, the role of microbes and the relevance of soil organic matter
Presenters: Daniel Geisseler, Radomir Schmidt and Margaret Lloyd
We will begin with an overview of the sources, transformations and fates of sources of organic nitrogen in soil. Foundational to this, we'll cover the role and dynamics of microbes in nitrogen management, and how that impacts management decisions. Lastly, we'll discuss using nitrogen budgets to understand the sources and proportions of available nitrogen to meet crop demand.
December 4, 2023 1-3 pm Part 2: Estimating nitrogen release from organic amendments and contributions from cover crops
Presenters: Patricia Lazicki and Margaret Lloyd
This session will focus on estimating nitrogen release from compost, organic fertilizers and cover crops. In addition, participants will be invited to apply the training to their own operations and receive feedback on the budget calculations during this session.
December 11, 2023 1-3 pm Part 3: Putting it all together: Completing a nitrogen budget, synchronizing nitrogen release with nitrogen demand, and using soil tests
Presenters: Daniel Geisseler, Joji Muramoto, Michael Cahn and Margaret Lloyd
In this session, we will address specific aspects of organic soil fertility management in vegetables. Discussions will include nitrogen in irrigation water, managing water for nitrogen optimization, crop nitrogen demand and strategies to supply demand, as well as using and interpreting soil testing. Specific references will be made to strategies for complying with forthcoming regulations. We will conclude with a discussion on new frontiers in plant's nitrogen acquisition science.
December 18, 2023, 1-3 pm part 4: Open house (Grower Panel)
In this session we will have 1-2 growers share their experience managing nitrogen on their farms. Then, we will open it up to questions, share experiences and discuss the nitrogen budget file. Attendees will be encouraged to bring their own data to receive feedback.
About the Presenters
Daniel Geisseler is an associate Cooperative Extension Specialist in the Department of Land, Air and Water Resources at UC Davis. Daniel's research and outreach focuses on nutrient turnover and plant nutrition in agricultural systems. He is interested in the effects that different management practices have on nutrient use in California crops and how nutrient use efficiency can be improved, particularly with nitrogen. |
|
Patricia Lazicki is the Vegetable Crops Advisor for Yolo, Solano, and Sacramento Counties, working mainly in tomatoes. Her research interests include soil health, and nutrient management and fertility in organic annual cropping systems. |
|
Margaret Lloyd is the Organic Agriculture and Small Farms Advisor for Yolo, Solano and Sacramento Counties. She runs an active research and outreach program focused on nutrient management and pest management for organic vegetable farms. |
|
Joji Muramoto (joji@ucsc.edu) is an assistant Cooperative Extension organic production specialist at UC Santa Cruz. His research and extension focus on nitrogen and soilborne disease management in organic cropping systems across the state. |
|
Radomir Schmidt is a program manager at the Working Lands Innovation Center at the UC Davis Institute of the Environment. As a soil microbiologist, Radomir conducts research on the effects of specific farming practices (organic amendment application, enhanced rock weathering, cover cropping, no-till systems) on carbon sequestration and greenhouse gas fluxes in soils, and on the the roles of microbial communities in soil health improvement and maintenance. |
|
Michael Cahn (mdcahn@ucanr.edu) is an irrigation and water resources Farm Advisor for UC Cooperative Extension in Monterey County. His research and extension program focuses on irrigation efficiency, nutrient use of crops, and protecting water quality. He led the development of CropManage, an online decision support tool for irrigation and nutrient management. |
/table>