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Good news for hedgerows: No effects on food safety in the field

The native California shrub toyon, or Christmas berry, blooms with white flowers in a hedgerow planted behind Rachael Long and a tomato grower.

Hedgerows enhance wildlife abundance and diversity around farmland without contributing to food safety problems in field crops, according to a new study published by a team of University of California researchers. The UC Agriculture and Natural Resources and UC Davis study documented that field edge plantings around farms are generally too narrow relative to the surrounding landscape to be a source of rodents and foodborne pathogens.

“This study is particularly pertinent right now when FDA's Food Safety Modernization Act (FSMA) is calling for farmers to co-manage wildlife and agriculture, instead of clear cutting wild habitat around their crops,” said co-author Rachael Long, UC Cooperative Extension farm advisor in the Sacramento Valley. “Our paper provides support for this ruling, showing that the presence of hedgerows does increase wildlife diversity, but does not increase wildlife intrusion into the fields and, more importantly, does not increase the prevalence of animals carrying foodborne pathogens.”

This is good news for hedgerows, rows of shrubs, trees, grasses and flowers that are planted on field edges. The plants bordering crop fields provide habitat and floral resources for beneficial insects, such as bees and natural enemies, that help with pollination and biocontrol of pests in adjacent crops. Hedgerows also help enhance biodiversity – especially for insect-eating birds – help reduce wind and soil erosion, and protect water quality.

The two-year study in Sacramento Valley walnut orchards and processing tomato fields was led by Long and Roger Baldwin, UC Cooperative Extension vertebrate pest control specialist at UC Davis, former graduate student Laurel Sellers, the Western Center for Food Safety at UC Davis's Michele Jay-Russell, Xunde Lib and Edward R. Atwill, and Richard M. Engeman of USDA National Wildlife Research Center.

The study, titled “Impact of field-edge habitat on mammalian wildlife abundance, distribution, and vectored foodborne pathogens in adjacent crops,” was published in the February 2018 Crop Protection (Sellers et al. 2018).

Elsevier is providing 50 days of free access to this article. Anyone clicking on the following link before March 31, 2018, will be taken directly to the article on ScienceDirect. No signup or registration or fees are required. Simply click and read at https://authors.elsevier.com/c/1WXU~xPFYej~4.

Winter migratory birds like to eat the lovely red berries of toyon.

This journal article supports a growing body of literature suggesting that plantings along the edge of fields do not substantially attract wildlife species that intrude on fields and transfer foodborne pathogens. For example, in a 2015 study, UC Davis researchers found more food pathogens when wildlife habitat was reduced on farms. This may be attributed to the vegetation filtering pathogens, a better breakdown of pathogens in diverse environments, and that removing vegetation may not deter wildlife from entering farm fields.

Relative to the larger crop acreage, hedgerows and similar field-edge habitats are generally too linear and small to serve as a significant source of rodents to damage nearby crops. However, cottontail rabbits favor hedgerows, and can sometimes cause damage to adjacent seedling crops. 

“Overall, we found risk of crop loss or contamination of foodborne pathogens in crops bordered by hedgerows wasn't significant in our study in the Sacramento Valley, although potential damage could vary by the stage and type of crop and wildlife species present,” Long said. She will be presenting this work at the 28th Vertebrate Pest Control Conference, which will be held in Rohnert Park Feb. 26 to March 1.

In its Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption, the U.S. Food and Drug Administration says, "We continue to encourage the co-management of food safety, conservation, and environmental protection.

Hedgerows, the plants bordering this field of processing tomatoes, provide habitat and floral resources for beneficial insects that help pollinate crops and provide natural control of pests.

Further reading:

Hedgerow benefits align with food production and sustainability goals. http://calag.ucanr.edu/archive/?article=ca.2017a0020

Comanaging fresh produce for nature conservation and food safety. http://www.pnas.org/content/112/35/11126

 

 

 

 

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Posted on Thursday, February 15, 2018 at 10:47 AM
Tags: Food Safety (4), Hedgerows (4), Rachael Long (8)
Focus Area Tags: Agriculture Environment

UC launches drought video series Feb. 2

Because periodic droughts will always be a part of life in California, the UC California Institute for Water Resources (CIWR) produced a series of videos to maintain drought awareness and planning, even in years when water is more abundant.

The first of the three videos premieres Feb. 2 on the UCTV Sustainable California channel. Subsequent videos will be launched March 2 and April 6. View the trailer here.

The videos are inspired by a collection of 19 drought tips produced by CIWR in collaboration with UC Agriculture and Natural Resources researchers during the drought of 2010-16. The tips cover a broad spectrum of California crops, from alfalfa to walnuts. Topics also include salt management, use of graywater in urban landscapes, and the use of shallow groundwater for crop production. Three topics – alfalfa, almonds and citrus – are featured in the three-episode CIWR video series.

UC Cooperative Extension alfalfa specialist Dan Putnam wrote the drought tip 'Drought strategies for alfalfa,' on which the first video in the series is based. The video is on the the UCTV Sustainable California channel, https://www.uctv.tv/sustainable-cal/.

The drought tips collection and the drought tip videos were sponsored by the California Department of Water Resources. Following is the schedule for the video releases:

Friday, Feb. 2: Drought strategies for alfalfa

The CIWR drought tip series opens with Cannon Michael of Bowles Farming in Los Banos. The alfalfa grower works with UCCE specialist Dan Putnam. “There's a lot of misunderstanding about alfalfa as a crop,” Michael said. “It does take water to grow it, as with anything, but you get multiple harvests of it every year.”

Friday, March 2: Drought management for California almonds

The second episode features almond producer Raj of Meena farms. He works with David Doll, UCCE advisor in Merced County. “One positive of this drought,” Meena said, “is that it has forced us all to be more efficient in how we use our water.”

Friday, April 6: Irrigating citrus with limited water

The series finale features Lisa Brenneis of Churchill-Brenneis Orchard in the Ojai Valley of Ventura County. She worked with UCCE advisor Ben Faber to install a new water-efficient irrigation system. “Irrigation is the only job we really have to do,” Brenneis said, “and we have to get it as right as we can.”

For a complete list of drought tips, see http://ucanr.edu/drought-tips.

Posted on Friday, February 2, 2018 at 8:30 AM
Tags: Dan Putnum (1)
Focus Area Tags: Agriculture

Flooding alfalfa fields has high potential for groundwater recharge

A rigorous field study in two California climate zones has found that alfalfa can tolerate very heavy winter flooding for groundwater recharge. The research was published online Jan. 16 in California Agriculture journal.

The alfalfa research is the latest in a series of projects studying the effects of using land planted with permanent crops – including almond orchards and vineyards – to capture and bank winter storm water. Such projects have great promise but also require collaboration across multiple jurisdictions and agencies. UC Agriculture and Natural Resources vice president Glenda Humiston has made groundwater recharge on working lands and open spaces a division priority and is working with water and land use leaders around the state to facilitate it through policy recommendations and cross-agency collaboration.

Flooding an alfalfa field for groundwater recharge. (Photo: Andrew Brown)

Groundwater is a critical water reserve in California, particularly during droughts when surface water supplies are low. Water slowly filled California's aquifers over tens of thousands of years. Beginning in the early 20th century and continuing in the present day, groundwater has been consistently withdrawn at a higher rate that it can be replenished naturally. In 2014, the California Legislature enacted the Sustainable Groundwater Management Act, which requires all critically overdrafted groundwater basins to have a groundwater sustainability plan in place by 2020. 

Flooding agricultural land during the winter, when surplus surface water is often available, is one promising strategy for replenishing overdrafted aquifers.

View a four-minute video about on-farm flooding for groundwater recharge on the UCTV Sustainable California channel. In the video, Professor Helen Dahlke discusses the work she and her fellow UC Davis researchers, UC Cooperative Extension advisors and specialists, and California farmers are undertaking to test the impacts of irrigating almond orchards in the winter to recharge groundwater.

For the alfalfa flooding research, UC Davis and UC Cooperative Extension scientists flooded two established alfalfa stands, one near Davis and one in the Scott Valley, Siskiyou County, during the winters of 2015 and 2016. The sites were selected because the soils in those areas have relatively high water percolation rates.

Integrated hydrologic science professor Helen Dahlke in an almond orchard being flooded for groundwater recharge.

“We found that most of the applied water percolated to the groundwater table,” wrote lead author Helen Dahlke, integrated hydrologic science professor at UC Davis.

The alfalfa endured saturated conditions in the root zone for a short time, but the yield loss was minimal.

Dahlke and her co-authors – USDA Natural Resources Conservation Service soil scientist Andrew Brown, and UC Cooperative Extension specialists Dan Putnam and Toby O'Geen and the late UCCE advisor Steve Orloff  – noted that the positive results of the alfalfa trial show tremendous potential for the state's groundwater basins. Using an index created by O'Geen that identifies the locations of California soils suitable for on-farm groundwater recharge, the scientists calculated the potential groundwater recharge. If all the suitable alfalfa acreage were flooded with six feet of winter water, and assuming 90 percent percolates past the root zone, it would be possible to bank 1.6 million ac-ft. of groundwater per year.

“For reference, the Oroville reservoir, second largest in the state, has a storage capacity of 3.5 million ac-ft.,” Dahlke wrote.

Leigh Bernacchi, program coordinator of UC Water at UC Merced, interviewed Helen Dahlke to get more details on groundwater recharge strategies for California. Read the Q&A on the UC Water Center website.

Additional reading:

Posted on Friday, January 19, 2018 at 8:41 AM
Tags: groundwater (5), Helen Dahlke (1)
Focus Area Tags: Agriculture Natural Resources

Ag leaders, scientists set priorities to prevent invasive pest threats to the environment and economy

The gypsy moth, an interloper from Europe and Asia, is threatening California's majestic oaks in Ventura County.

Invasive desert knapweed, which comes from Africa, has made its first North American appearance in in California's Anza-Borrego Desert, where it has started to crowd out native plants.

Asian citrus psyllids are slowly spreading the devastating huanglongbing disease in Southern California citrus.

River rats from South America, called nutrias, are munching voraciously on wetland plants in some areas of Stanislaus, Merced and Fresno counties.

These are just a few of the insects, weeds, animals and diseases that have entered the state of California from elsewhere on the globe, causing tremendous ecological damage and huge economic losses to agricultural crops, which ultimately affect every resident of California.

Based on historical data, a new invertebrate species establishes itself in California about every six weeks, on average. They don't all become serious pest problems, but many evade eradication efforts, disrupt carefully balanced integrated pest management programs, hijack sensitive ecosystems, and spoil valued recreational resources and urban landscapes.

A diverse group of university scientists, federal and state government representatives, county agricultural commissioners and non-profit organization leaders who are battling these pests converged at a summit in the state capitol Jan. 11 and 12 to coordinate their efforts, pool intellectual resources, and plot a strategy for protecting agricultural crops, natural resources, unique ecological communities, cityscapes and residential neighborhoods.

“We are a big, beautiful, special place, blessed with great weather and diverse geography,” said California Department of Food and Agriculture Secretary Karen Ross at the summit. “That means a lot to our many visitors – including pests.”

Glenda Humiston, vice president of UC Agriculture and Natural Resources, said research is a fundamental component of the fight against damaging invasive species.

Glenda Humiston, vice president of UC Agriculture and Natural Resources, which co-sponsored the summit, outlined the goals.

“We know that collectively, we have the tools and expertise to prevent invasive species from entering California, spreading and becoming established,” Humiston said. “I am so pleased with the numbers of people here today, and the expertise that you bring.”

A fundamental component of the fight against damaging invasive species is research, Humiston said, adding that the European grapevine moth in an apt example. The pest was detected in California's wine country in 2009, and later found as far south as Fresno County. A multi-agency collaboration responded quickly.

UC ANR academics studied the moth's biology, life cycle, host range and proven management practices. They developed a pest management program that relied on mating disruption with pheromones and application of carefully timed insecticides. In short order, the moth population plummeted, and the state was declared free of European grapevine moth, lifting a quarantine, enhancing farmers' ability to export its product, and preserving the communities' economic wellbeing.

“This multi-agency collaboration contributed to a successful, science-based response plan to a serious pest threat,” Humiston said.

She noted, however, that prevention is the best option.

“This is critical,” Humiston said. “Once the pests are here, they cost us millions upon millions of dollars to manage, not to mention the devastation and destruction inflicted on our crops, natural resources and the damage to local economies.”

In 2010, CDFA created a strategic framework for addressing California's ongoing invasive pest problems and potential future introductions. Successful implementation of the framework requires partnerships involving government from the state to local levels, the agriculture industry and commodity groups, non-governmental organizations committed to the environment, and researchers at UC and other universities.

UC Cooperative Extension advisor emeritus John Kabashima led a break out session on arthropods during the summit.

UC Cooperative Extension advisor emeritus John Kabashima was instrumental in bringing the summit to fruition. Kabashima, who retired in 2015, continues to lead a battle against invasive shot hole borer pests in Southern California. The insects, originally from Asia, are killing thousands of Southern California trees, and have the potential to kill millions of trees in urban areas, natural areas and even on farms in parts of the state as far north as Sacramento.

“We convened this meeting to bring together experts in the field and people who are feeling the impacts,” Kabashima said. “We're trying to start a 21st century invasive pest program that would then be implemented and funded to address the urgent issues before they cause any more devastation.”

Summit participants prepare to vote on most pressing invasive species' issues and best management strategies.

At the end of the two-day summit, the participants voted to decide the most pressing issues and best strategies to take forward to their agencies, coalitions, research groups, legislators and constituents. Key strategies that emerged were:

  • Analyze the economic impacts of invasive species management and the cost of “doing nothing.”
  • Develop and maintain statewide surveys and map high-risk surveys.
  • Increase funding to study invasive species' biology. 
  • Create a standing rapid response workgroup to guide response to new invasive species. Fund a rapid response emergency fund.
  • Enact regulations to control high-risk vectors, such as soil, green waste, gravel, forage, straw and firewood.
  • Formalize the Invasive Species Council of California (ISCC) and the California Invasive Species Advisory Committee (CISAC).

Mark Hoddle, UC Cooperative Extension biological control specialist and director of the Center for Invasive Species Research at UC Riverside, said the summit was a valuable part of the ongoing battle against invasive pests.

“It's good to see the number of agencies and organizations involved with invasive species issues,” Hoddle said. “I'm impressed with the energy in coming up with these priority lists.”

Summit outcomes will include sending recommended action items to the Legislature for funding consideration.

“Without financial support, many of the management tools that prevent unwanted incursions, find and monitor incipient pest populations, and develop sustainable, cost-effective management programs won't be possible,” Hoddle said.

View Glenda Humiston's opening remarks here: 

Posted on Thursday, January 18, 2018 at 8:21 AM

Dig it, Grow it, Eat it: School gardens support learning and healthier food choices

Different edible parts of plants are on display (roots, stems, flowers, leaves and seeds) for students to have hands-on learning in the garden. (Photo: UC Master Gardener Program Marin County)

The success of a garden is normally identified by plentiful crops of tomatoes and squash or the beautiful display of vibrant thriving flowers, shrubs or trees. However, a school garden's true success is dependent on the rich experiences and education students receive.

Taking the classroom into the garden

School gardens can play a big part in supporting a child's education outside of the traditional classroom environment; offering hands-on learning experiences in a variety of core curricula. Social sciences, language arts, nutrition and math are just a few of the many subjects that can be easily integrated into the school garden curriculum.

When paired with nutrition education, school gardens can transform food attitudes and habits.

“Gardens containing fruits and vegetables can change attitudes about particular foods; there is a direct link between growing and eating more fruits and vegetables,” said Missy Gable, statewide director for the UC Master Gardener Program. “Programs statewide connect people to local community gardens, or provide school administrators and staff the information needed to get started with their own school, community or home garden.” 

UC Master Gardener volunteers in Marin County connect gardening topics to science and nutrition in portable field trips for their award-winning project, "Dig it, Eat it, Grow it." (Photo: UC Master Gardener Program Marin County)

“Dig it, Grow it, Eat it”

The UC Master Gardener Program of Marin County hosts an award-winning school gardening program that emphasizes engaging students with the many learning opportunities in nature. The program is a portable field trip for school-age youth called “Dig it, Grow it, Eat it.”

“Dig it, Grow it, Eat it” starts with University-trained UC Master Gardener volunteers training school educators. Once trained, educators use the curriculum to teach students how to grow edible plants from seed to harvest. UC Master Gardener volunteers help deliver the curriculum and provide additional resources. Students learn how plants grow, and receive nutrition lessons to give them a better understanding of the human body's need for healthy food.

Students learn about healthy soil and the benefits of composting from a UC Master Gardener volunteer during a "Dig it, Eat it, Grow it" school field trip. (Photo: UC Master Gardener Program Marin County)

The half-day workshop rotates groups of students through six stations providing them with garden enhanced nutrition education, linking health with growing and harvesting foods they like to eat and are good for them. These include:

  • Edible Plant Parts
  • How Plants Grow
  • Plant Seed Science
  • Propagation
  • Soil Science

The “Dig it, Grow it, Eat it” curriculum is centered on the theme “We love the earth because we care for it. We care for the earth because we love it.” For many children, getting their hands dirty in the garden and discovering the science of growing their own food brings a sense of joy and pride they can carry with them for years to come. 

Connect with us

The UC Master Gardener Program extends to the public free UC research-based information about home horticulture and pest management. In exchange for the training and materials received from the University of California, UC Master Gardeners perform volunteer services in a myriad of venues. If you are interested in becoming a certified UC Master Gardener contact your local UC Cooperative Extension office or visit mg.ucanr.edu

 

Posted on Wednesday, January 17, 2018 at 11:43 AM
Focus Area Tags: Yard & Garden

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