- (Focus Area) Agriculture
- Author: Jeffrey P Mitchell
CASI's Mitchell on MyAgLife podcast June 28, 2024
July 1, 2024
Jeff Mitchell, CASI member and Professor and Cropping Systems Cooperative Extension Specialist in the Department of Plant Sciences at the University of California, Davis, appeared in a 39-minute podcast with host Taylor Chalstrom on June 28, 2024 to talk about conservation agriculture in general and the recently-published article in California Agriculture on the 20-year study in Five Points, CA. The podcast is available at
https://spotifyanchor-web.app.link/e/JuQ7qakGSKb
You may need the podcast platform, Spotify, to listen to it.
/span>![MyAgLife June 28, 2024 Image MyAgLife June 28, 2024 Image](/blogs/blogcore/blogfiles/107597.png)
- Author: Humboldt Del Norte Counties Help Desk Team
![Weeds in a pasture. Weeds in a pasture.](http://ucanr.edu/blogs/CoastalGardener/blogfiles/107589.png)
Q: I have lots of weeds in my orchard. I've tried hand pulling and a high concentration of vinegar without much success to get rid of the stinging nettle, horsetail, hemlock, and wild radishes. Can I use herbicides?
A: So, what is a weed? It is a plant that is out of place, unwanted, or interferes with crop or livestock production. Weeds can also protect and restore exposed soils, provide habitat for beneficial organisms, such as pollinators, make nutritious food and fodder, and replenish and restore soil life.
Weed management includes hand pulling, mowing, decreasing the seed bank, and allowing them to grow in a controlled manner. Using herbicides is another tool in the toolbox and are effective when applied with knowledge and safety. Here are some resources for you about the identified weeds and the use of herbicides/pesticides. We encourage you to follow all directions and precautions when using chemicals so that you do not harm yourself or the environment.
Resources:
Weeds – Identifying and Controlling https://ucanr.edu/sites/hdnmastergardeners/Resources_for_Home_Gardeners/Weeds_-_Indifying_and_Controlling/
Weed Control in the Vegetable Garden
https://yardandgarden.extension.iastate.edu/how-to/weed-control-vegetable-garden#herbicides
How to Manage Pests in Gardens and Landscapes, Burning & Stinging Nettles https://ipm.ucanr.edu/PMG/PESTNOTES/pn74146.html
Common Horsetail, U.S. Forest Service https://www.fs.usda.gov/wildflowers/plant-of-the-week/equisetum_arvense.shtml#:~:text=Equisetum%20arvense%20range%20map.,Common%20Horsetail%20(Equisetum%20arvense)
It's True What They Say About Horsetails, Patricia Matteson, December 20, 2022 https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=55810
Horsetails Weed Report from the book Weed Control in Natural Areas in the Western United States
https://wric.ucdavis.edu/information/natural%20areas/wr_E/Equisetum.pdf
How to Manage Pests in Gardens and Landscapes, Poison Hemlock
https://ipm.ucanr.edu/PMG/PESTNOTES/pn74162.html
UC IPM Pesticide Information, Active Ingredient: 2, 4-D
https://ipm.ucanr.edu/TOOLS/PNAI/pnaishow.php?id=3
Warning in the Use of Pesticides, https://ipm.ucanr.edu/PMG/PESTNOTES/warning.html
UC IPM Weed Gallery – Wild Radish https://ipm.ucanr.edu/PMG/WEEDS/wild_radish.html
- Author: John Lovett
- Posted by: Gale Perez
Pair of studies offers evidence into "superweed's" defensive tactics, strategy
FAYETTEVILLE, Ark. — A study of the effects of mowing on a common weed has found that what doesn't kill you can make you stronger.
A study published in Nature's Scientific Reports has found that frequent mowing of Solanum elaeagnifolium may help create a “superweed.”
Solanum elaeagnifolium — also known as silverleaf nightshade — can be found from south Texas to South Africa and Greece, infesting fields and soaking up valuable nutrients intended for cash crops. The weed with purple flowers – sometimes white and light purple – has prickly spines and poisonous berries.
Relatives of the plant, including Solanum ptychanthum or black nightshade, and Solanum carolinense, or Carolina horsenettle, also produce toxic berries and are native to Arkansas. It's a family that also includes some friendly crops such as tomatoes, potatoes, peppers and eggplants.
Rupesh Kariyat, an associate professor of entomology and plant pathology with the Arkansas Agricultural Experiment Station, has been studying silverleaf nightshade for more than a decade. Kariyat began the study while at the University of Texas Rio Grande Valley, when he and his graduate student Alejandro Vasquez took on what turned into a five-year, two-part study to observe the effects of frequently mowed silverleaf nightshade. Kariyat joined the experiment station, the research arm of the University of Arkansas System Division of Agriculture, in 2022.
Although studies have often highlighted weed fitness and defense traits resulting from disturbances like mowing, most were limited to foliar, or leaf, defenses, Kariyat said. That changed when Vasquez and fellow master's biology students at the University of Texas Rio Grande Valley monitored fields of mowed, unmowed and frequently mowed silverleaf nightshade in and around Edinburg, Texas.
“Alejandro's question was, ‘how do these flowers differ between mowed and unmowed plants?'” Kariyat said. “‘And does that have consequences for the insects that actually feed on them?'”
Self-defense strategies
Findings in both studies showed that the more silverleaf nightshade was mowed, the more it developed ways to avoid destruction, Kariyat said. The taproot went down further, nearly 5 feet deep, in the first generation of mowed plants. More spikes popped out on the stem as a defense against caterpillars feeding on the flowers. The flowers became more toxic to caterpillars, leading to less pressure from natural predators.
Like time bombs, the plant produced some groups of seeds that germinated faster and others that were delayed. This “staggered” germination was the plant's way to ensure survival over the long haul.
“You are trying to mow these plants so that the plants are getting eliminated,” Kariyat said. “But what you are actually doing here, you are making them much worse, much stronger.”
Tilling areas with silverleaf nightshade also spreads the plant because the rhizomic roots, like many weeds, can propagate asexually over multiple years and growing seasons.
The observations of mowed, unmowed and frequently mowed areas with silverleaf nightshade provide evidence that could prompt further studies by weed scientists on best management practices, Kariyat said.
Since the studies focus solely on silverleaf nightshade, Kariyat said other weeds — even the plant's family relatives — may or may not react the same way to frequent mowing. However, the study does provide more insight into the defensive capabilities of plants pitted against human disturbance.
“This should be something that we consider when we make management plans,” Kariyat said of the plant's defenses. “Management practices need to be better understood using the ecology and biology of the species and the other species which interact with them.”
Kariyat and Vasquez published their results in April with an article titled “Continuous mowing differentially affects floral defenses in the noxious and invasive weed Solanum elaeagnifolium in its native range.” Vasquez, now an entomology and plant pathology Ph.D. student at the University of Arkansas, was the lead author. Co-authors included Kariyat, Alexa Alaniz, and Robert Dearth, founding director of the School of Integrative Biological and Chemical Sciences at the University of Texas Rio Grande Valley.
“As scientists, we want our research to be accessible and applicable to anyone, and mowing is a concept the world at large can understand,” Vasquez said.
The initial study was published in 2021 with an article titled “Local adaptation to continuous mowing makes the noxious weed Solanum elaeagnifolium a superweed candidate by improving fitness and defense traits.” The lead author for that study was Jesus Chavana, with co-authors Sukhman Singh, Bradley Christopherson, Alexis Racelis, Vasquez and Kariyat, all with the University of Texas Rio Grande Valley at the time.
For more on the topic, please check out the Food, Farms & Forests podcast episode “Mow less: Studies Show Less is More When Mowing Noxious Weed.”
John Lovett is the Science Writer with Agricultural Communications Services at the Arkansas Agricultural Experiment Station, University of Arkansas. He can be reached at jlovett@uada.edu or (479) 763-5929.
Original source: EurekAlert! • June 3, 2024
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- Author: Michael 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.
/h3>/h3>/h3>- Author: Trina Kleist, UC Davis
Still providing the world with top-notch information
UC Davis has been a leading source of information for people handling, packaging and transporting crops since the beginnings of the Postharvest Research and Extension Center in 1979. Now, the center is strengthening its focus on the needs of industry, offering fresh courses, weaving strategic partnerships and expanding into digital media, all while building up its research capacity to better serve the needs of the produce industry.
“We're asking people in the industry, ‘How can we support you? How can we better listen to you?' We want people to know we're not disconnected know-it-alls,” said new center co-director Bárbara Blanco-Ulate, an associate professor in the UC Davis Department of Plant Sciences. “We're getting more faculty involvement, people with expertise in related fields such as quality engineering and safety, as well as bringing in emeriti faculty and people from around California. We're forming partnerships with organizations around the world, and we've opened up to people from other institutions around the country.”
“The larger the network, the more things we can do,” added fellow co-director Irwin R. Donis-Gonzalez, an associate professor of UC Cooperative Extension in the Department of Biological and Agricultural Engineering.
The foundation: Expanded research
The new co-directors will beef up the center's applied science component with the hiring of a research specialist. They aim to provide new information that can be used industry-wide as companies explore new ways to handle and store fresh produce.
“We're building the capacity to respond to industry requests for research,” Blanco-Ulate said.
New courses, national reach
Their first workshop, held recently, demonstrates the center's renewed vision and commitment to broad networking: The Agricultural Water Systems Workshop addressed current concerns around water management and risks to food safety. Partners in the course included the Western Growers Association, the University of Arizona, the University of Florida and Salinas-based Taylor Fresh Foods, Inc.
Courses given over the past several years that have been recorded will be posted to the center's new, online video library and to the center's YouTube channel.
“People can watch those courses for free,” Blanco-Ulate said. In addition, new courses will be offered in-person and hybrid.
The co-directors are working with the University of California to offer continuing and professional education credits to course participants.
Online resources – many for free!
The center's website features a database with scores of free product fact sheets, which are downloaded by users around the world. The fact sheets are so highly regarded that they are considered expert evidence in legal proceedings, Blanco-Ulate said. Visitors to the website can also find links to research papers published by UC Davis faculty, including seminal works by Adel Kader, who founded the center.
Books are offered through the center's online bookstore and include titles through UC Agriculture and Natural Resources. Ten new titles are being planned, including topic-specific updates taken from previous classics.
Debunking myths: Ethylene
A new newsletter deals with a new problem: Misinformation about food and food handling that spreads through social media. One example is the use of ethylene to ripen produce such as bananas, so that they can be safely stored until ready for the consumer.
“Ethylene is safe for humans and does not leave any harmful residue on produce,” Donis-Gonzalez wrote in the center's latest newsletter. Even better news, he added: The levels of ethylene used on food are a tiny fraction of the concentrations that would be needed to create an explosion, one of the false alarms being raised in social media.
Evolving with the times
After 47 years of service, these and more updates will keep the center at the forefront of an evolving postharvest world. The top goal: Meet the needs of agriculturalists, industry and consumers.
“We are adapting to new needs, with both the resources and the workshop we're offering,” Donis-Gonzalez said.
“As a land-grant institution, we take our outreach mission seriously,” Blanco-Ulate added.
Related links
More about the UC Davis Postharvest Research and Extension Center.
This story first appeared on the UC Davis Department of Plant Sciences site.
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