Stretching from the Death Valley to Calexico, California's vast dry desert is home to a unique and important agriculture industry.
It's a place where summertime temperatures often top the 115-degree mark. Where water supplies for irrigation depend on the Colorado River, but upriver states are claiming more of it. Where evapotrasporation – a reference rate of water use in unstressed turf grass – is 72 inches per year, but rainfall is rarely more than 4.
Still, stalwart farmers grow dates, carrots, lettuce, broccoli, cabbage, kale and more, plus plants for landscaping everything from family homes to beautiful and luxurious resorts. The agriculture output of the state's three desert counties – Riverside, San Bernardino and Imperial – exceeds $4 billion annually.
The California desert also impacts the quality of life across the nation. If Americans are enjoying a salad in the winter, the lettuce most likely was grown in the California desert. There are bountiful winter recreation opportunities available on the beautifully manicured golf courses, parks and landscapes.
A group of UC Agriculture and Natural Resources (UC ANR) academics formed a desert workgroup to better serve the state's desert region. The group organized a symposium in February to bring together representatives from desert farm and natural resources communities, related industry and academics working in the desert.
“The close exchange of information among desert researchers, non-profit organizations, industry and clientele groups will facilitate collaboration among UC ANR, Arizona and Mexico and foster how our programs should be shaped on a regional level,” said Oli Bachie, the director of UC Cooperative Extension in Imperial County and the current workgroup chair.
With saline soil, scorching summer temperatures and limited water supplies, the desert could be considered a hotbed of the “wicked problem.” A wicked problem isn't evil, said UC Associate Vice President Wendy Powers, the symposium's plenary session keynote speaker.
“The term ‘wicked problem' was coined at UC Berkeley,” Powers said. “It's a problem with circumstances that resist resolution.”
She named climate change and the growth of the global population California must help feed as wicked problems faced by the state. Powers described UC ANR's statewide programs that are working to find solutions to formidable issues faced in California agriculture.
“We're on the verge of some serious breakthroughs as we look at solving wicked problems,” Powers said. “They are accelerated by conversations like those we're having today.”
UC Vice Provost Mark Bell said that the potential of UC ANR to reach every single Californian is what drew him to his position in 2017. Bell invoked Star Wars robot R2D2 for an acronym to reflect the characteristics that accurately define UC ANR.
“R2 stands for reach and relevance,” he said. “D2 is diverse and dispersed.”
UC Cooperative Extension offices serve 57 California counties and its nine research and extension centers are located in key agriculture ecosystems, including one in the low desert of the Imperial Valley.
The afternoon program of the symposium included breakout sessions to highlight programs and research efforts in three broad areas: irrigation and crop production, landscape management, and livestock and feed quality.
“This was the first attempt to organize such a regional desert-based symposium for the UCANR Desert Workgroup with the collaboration of desert-serving UCCE counties,” Bachie said. “I believe that we have registered a remarkable get-together.”
The symposium had speakers and participants from UC, USDA, California Department of Food and Agriculture, the desert agricultural industry, pest control advisors, non-profit institutions and organizations, agricultural commissioners, farm bureaus, Arizona and Mexico universities and the general public.
“I believe that the symposium is a stepping stone for future desert research and extension meetings, conferences and symposiums among people engaged or interested in desert agriculture and natural resources,” Bachie said.
Although individual extreme weather events cannot yet be reliably linked to global climate change, the warming planet may be contributing to recent weather disasters in California. Across the state, 129 million trees died as a result of the drought of 2011-2016, many of them in the Sierra Nevada. Last fall, the worst wildfires in the state's history whipped through wildland areas and neighborhoods, and then were followed by a January deluge and deadly mudslide.
Climate change is also impacting agriculture. The winter chill that farmers rely on to re-boot cherry, pistachio, walnut and other important fruit and nut crops has been curbed by unseasonably warm nighttime temperatures. Sustained summertime heat waves are damaging crops and putting diminishing water resources under stress.
Climate change isn't just about the planet. Increased frequency and intensity of climate extremes impact peoples' lives by forcing evacuations and migration from fire- and flood-prone areas, reducing the availability and safety of food, and dampening emotional well-being.
How can Californians grapple with climate change?
On the front lines of climate change education, mitigation and adaptation is UC Cooperative Extension (UCCE), with its network of scientists headquartered throughout the state, living and working in communities where local climate change impacts must be addressed.
In 2015, UCCE's parent organization, UC Agriculture and Natural Resources (UC ANR), formed a Climate Change Program Team to lead a coordinated effort by UC ANR staff and academics dealing with climate change. The team surveyed UC ANR academics to find out about their current role in California climate change resilience.
“Eighty percent of respondents thought incorporating climate change impacts, mitigation and adaptation in their programs is important,” said UCCE specialist Ted Grantham, a member of the program team. “Less than half are actually doing so.”
The barriers respondents shared to working on climate change include technical complexity, lack of relevant information, and discomfort with the difficult conversations climate change can trigger. The program team brought together a diverse group of specialists, advisors and staff for a two-day workshop in February to increase capacity to raise public awareness about climate change, find practical ways to reduce the impacts of climate change, and help communities adapt to the reality of a changing planet.
Keynote speaker Michael Crimmins, a climate science extension specialist at the University of Arizona, said land-grant outreach programs have the interdisciplinary expertise and connections to provide decision support to farms and communities facing a warming world.
“Climate change is too big to tackle alone,” he said. “We have a lot of programs that can nibble at the edges. If everyone nibbled at the edge, we can make a difference.”
Resources are available for climate change extension
Myriad climate change resources were presented. UC Davis professor Arnold Bloom shared a free online college course posted at http://climatechangecourse.org. The course examines the factors responsible for climate change, the biological and social impacts, and the possible engineering, economic and legal solutions. Forty-eight mini-lectures, assignments and even exams are available to anyone willing to devote time to understanding climate change.
UCCE specialist Jeff Mitchell explained ongoing efforts to implement conservation agricultural practices on California row crop land. Research has shown the potential for climate change mitigation with precision irrigation and tillage reduction, practices that sequester carbon in the soil, reduce fertilizer needs, improve soil quality and increase yield.
Greg Ira, coordinator of the UC California Naturalist program, said a new advanced training module on climate stewardship is in development. The training will be provided to select certified California Naturalists, volunteers who work with partner organizations across the state on environmental stewardship, nature education and citizen science.
UCCE specialist Maggi Kelly introduced the website http://Cal-Adapt.org, which contains volumes of climate change projections and climate impact data from California's scientific community. Users can explore projected changes in temperature, precipitation, snowpack and sea level rise in California over this century with interactive climate data visualizations. They can download data, find peer-reviewed research and learn how to use climate projections.
Leslie Roche, UCCE rangeland management specialist, conducted rancher interviews after the 2011-2016 drought to gauge whether they consider climate change an important consideration for their ranching businesses, and whether they believe future climate will be different from the past. She found that ranchers are generally confident that they have the skills to manage for long-term drought, and that they are interested in learning about climate change and its potential impacts on their industry.
Roche has aggregated rangeland drought- and climate-management resources online at the Rangeland Drought Hub. The website includes “Voices from the Drought,” the personal stories of ranchers discussing the agonizing decisions they made during the drought – such as culling cattle, reducing staff, paying more for feed, and allocating limited water resources.
Steve Ostoja, the director of the USDA's California Climate Hub, said the program helps California farmers, ranchers, forest landowners and tribes maintain sustainable communities and ecosystems by adapting to climate variability and change. Guido Franco of the California Energy Commission said the organization recently released its fourth Climate Assessment. The assessment presents research on the impacts of climate change on the state, as well as strategies to dramatically reduce greenhouse gas emissions.
“I found the information and materials compiled by the Climate Change Program Team very useful,” Mitchell said. “I will be consciously using these in extension education when I can.”
UC California Institute for Water Resources academic coordinator Faith Kearns led a segment of the workshop on climate communication, taking into account the emotional side of climate change by practicing active listening and empathy building. She shared climate change communication strategies used by effective national advocates, such as Katherine Hayhoe, an evangelical Christian and climate scientist who recommends a soft approach that starts by establishing personal connections with individuals before diving into climate science.
Another approach is that of Sarah Myhre, a climate scientist at the University of Washington who believes scientists should speak boldly about climate change facts.
“… scientists are naturally risk-averse when it comes to public dialogue,” Myhre wrote in an essay on Guardian.com. “The verbal, argumentative skills common to professions in law, politics, or business do not come easily to most scientists. … Our job is not to objectively document the decline of Earth's biodiversity and humanity, so what does scientific leadership look like in this hot, dangerous world?”
At the meeting, UCCE advisor John Karlik pointed out that some listeners want to hear straight science, just facts.
“We're all needed,” Kearns said. “We all come with a difference set of circumstances and groups that we can connect with.”
The workshop closed with action planning and next steps. Among the needs presented during the session were:
- A climate change online portal with resources, tools and data that allow advisors and specialists to translate information into decision support.
- Simplified scientific information and case studies to personalize climate change impacts.
- Training for educators, advisors, specialists and volunteers.
- Research-based evidence on the impacts of climate change on food security and the cost of healthy food.
- A glossary of climate change terms.
In their article on the climate change survey in California Agriculture journal, the members of the UC ANR Climate Program Team said they believe UCCE is well positioned to understand and communicate the consequences of climate change to the public, and to identify strategies to mitigate negative outcomes for local economies, the environment and public health.
“UC ANR can become a powerful catalyst for climate adaptation and we should embrace a leadership role in advancing the knowledge and tools needed for a climate-resilient California,” they wrote.
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.
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.”
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
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.
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.
“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.
- Map identifies farmland with potential for groundwater recharge
- Flooding farms in the rain to restore groundwater
- On-farm flood capture could reduce groundwater overdraft in Kings River Basin
- Desperate Times Call for Sensible Measures: The Making of the California Sustainable Groundwater Management Act
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.”
“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 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.”
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: