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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 Beginning in the early 20th century and continuing in the present day, groundwater has been consistently withdrawn at a higher rate that it can be replenished naturally.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

Job Offer: Plant Manager Carriere Family Farms (Butte County)

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Posted on Thursday, January 18, 2018 at 10:53 AM

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

Newly minted UC fire scientist Kate Wilkin moves into fire country

Kate Wilkin inspects a ponderosa pine on her property with an old fire scar, undeniable evidence that fire has swept through her neighborhood in the past.

Fire scientist Kate Wilkin was on the job just a few weeks when ferocious winds whipped up the Northern California firestorm of 2017. The national media focused on Napa and Sonoma counties, where the deadly Tubbs fire became the most destructive wildfire in California history, while devastating fires also broke out in Butte, Nevada, Yuba and other counties.

It was crunch time for Wilkin, who stepped in as the new forestry, fire science and natural resources advisor for UC Cooperative Extension in Sutter, Yuba, Nevada and Butte counties that fall. Four lives and 200 homes were lost in her new work community. Wilkin will now host workshops to help families and businesses recover from the firestorm and rebuild in a way that is more resilient to fire. Fire resiliency will start at her own home.

The Wilkin-Johnston home is at the top of a rise dotted with cedars, ponderosa pines and black oaks. The dying plants in the foreground are Himalayan blackberry bushes that were treated with glyphosate (RoundUp) to remove them. The invasive weed forms a continuous understory that climbs into tree canopies and can carry fire with it. Wilkin removed one blackberry stem from a cedar tree that was more than 30 feet long.

From the Bay Area to the small town of Grass Valley

Wilkin and her husband Josiah Johnston moved into their first home, a ranch-style rambler atop a hill in Grass Valley, on Sept. 15, three days before Wilkin reported to work in the Sutter-Yuba County UC Cooperative Extension office in Yuba City.

The couple moved from a small apartment in Berkeley, where Wilkin was conducting research as a post-doc in the lab of UC Agriculture and Natural Resources researcher and UC Berkeley fire science professor Scott Stephens. The move from a hyper-urban Bay Area city to a small hamlet in the hills wasn't too much of shock to their systems. Johnston was raised on a farm with chickens and goats. Wilkin grew up in the rural Appalachia community of Abingdon, Va. After completing her bachelor's degree at the College of William and Mary, an internship with the Nature Conservancy in Kissimmee, Fla., introduced Wilkin to fire science.

“In the Disney Wilderness Preserve, the landscape would burn then flood every year,” Wilkin said. “I became fascinated with how these disturbances catalyzed diversity.”

What better place to continue a fire education than California?

Wilkin enrolled at CalPoly, San Luis Obispo, earning a master's degree in biology. She spent the next three years in Yosemite National Park, working with a team of scientists to understand the impacts of packhorse grazing in mountain meadows.

“We found that the current policies led to meadow degradation,” Wilkin said. Yosemite then changed its policy to reduce the amount of horse grazing on these tender, sensitive mountain resources.

Kate Wilkin and her husband Josiah Johnston in front of their Grass Valley home.

In 2011, Wilkin started work on her doctorate at UC Berkeley, where she studied the relationship between fire, forest diversity and water. Wilkin signed up for the pilot Graduate Students in Extension program at Berkeley, launched in 2014 to train and recruit graduate students for careers in research and outreach.

“The … internship gave me an amazing set of professional skills that I could practice, including media relations, public speaking to different audiences, and conference organizing and facilitating,” Wilkin told Science Magazine for an article about the innovative program. “Many of my colleagues and I see environmental problems and want to do applied research because we want to help find solutions.”

The railing and both sides of the siding on the deck were covered in wooden lattice by the previous homeowners. Wilkin and Johnston found a squirrel cache between the layers of lattice, with acorns, pinecones, needles and other dry plant debris. “It was the perfect place to start a fire,” Wilkin said.

Beginning at home

With full knowledge of the dangers of living in fire-prone areas, Wilkin and Johnston purchased a home close to the outdoor amenities they adore – hiking, backpacking and skiing.

“Tahoe is just an hour away,” Wilkin said. “I love the view from the house and the wooded setting. But we live in an area CalFire has designated as very high fire danger.”

As a fire scientist, Wilkin was well equipped to make changes to the home and landscape to minimize the risk.

“We moved in during peak fire season,” Wilkin said. “We didn't hang artwork. My priority was to make the home and deck more fire resistant. We put in one-eighth-inch mesh over the vents, caulked around doors and windows, blew leaves off the roof and deck, removed lattice wrapping the deck and cleaned the gutters. Then we created defensible space starting close to the house and working our way outward."

The couple labored about 200 hours and spent about $800 in the first six weeks buying and renting tools, including a chipper, saw and a truck to haul away tinder-dry lattice, foliage and pine needles. With the most critical fireproofing completed, the couple is now tallying the work that should be done to further enhance the fire safety of their home.

“We probably need another $6,000 to $7,000 of work,” Wilkin said.

To reduce large, hot embers from drifting into the basement and starting a fire in the home, Wilkin and Johnston installed one-eighth-inch mesh over the vents. Before next fire season, they will upgrade to vents that close during fires.

When the North Winds blow

Wilkin recalled the terrifying time about a month after moving into their new home when howling winds whipped around the house and fires were breaking out across Northern California.

“The North Winds are haunting,” she said. “I hadn't felt wind like that since I lived in Florida and experienced hurricanes.”

Wilkin and Johnston were fortunate. The closest fire to their home was the McCourtney Fire, which burned 76 acres in Grass Valley. The wildfire stayed two miles away.

A thick hedge of camellias borders the side of the home. Although ideally homes should have a five-foot zone immediately surrounding the house clear of burnable objects and plants, she didn’t have the heart to pull them all out when they were full of flower buds, but removed them after they bloomed.
 
Complex features on the roof – such as skylights, solar panels and a valley that can capture debris – require frequent maintenance to keep the roof fire safe. Johnston tacked down loose flashing on the roof and blew leaves off the roof and out of the gutters.
 
The previous homeowners installed a shrub-lined wood fence that went under the deck and attached to the house. “It was a perfect way for a fire to wick into the house,” Wilkin said. The couple removed the shrubs and fence slats and plan to remove the posts as well.
Posted on Tuesday, January 16, 2018 at 8:40 AM

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