Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

News stories

California groundwater could get recharging help from alfalfa farms

Researchers flooded alfalfa fields to recharge groundwater. Water application rates are determined based on soil physical properties and water intake rate. Photo by Helen Dahlke

When California experiences drought due to a lack of rain and snow and the reservoirs don't fill up, people pump water out of the ground to meet their needs. But that practice has its limits, as groundwater aquifers -- underground layers of porous rock -- get depleted, similar to how water squeezes from a sponge.

Many of California's groundwater aquifers, especially in the San Joaquin Valley, are critically overdrafted. They are being depleted faster than they are being recharged by water from the surface percolating through the soil to groundwater. Overdrafting is a concern because California relies on groundwater aquifers as a water storage and supply resource. They must be protected to ensure water security in the future. 

To direct surface water back into the aquifers, recharge basins are built, but they are limited in number and volume. Thinking of agricultural fields as potential recharge basins opens the possibility of increasing the number of locations where groundwater aquifers can be recharged. 

After six weeks of pulsed flooding for groundwater recharge, the alfalfa did not show a significant decline in yield. Photo by Helen Dahlke

Alfalfa is a crop that has a unique potential to support this practice because it is widely grown in the San Joaquin Valley and, in many cases, the plants are dormant or semi-dormant during the winter months. University of California researchers Helen Dahlke, Nick Clark and Khaled Bali are investigating how alfalfa copes with additional water in the winter and early spring, when snowmelt runoff occurs, for groundwater recharge.

“We hypothesized that water can be recharged in dormant and early regrowing established alfalfa fields successfully, and with little to no harm to the plants and the productivity as far as the farmer is concerned,” said Clark, a UC Cooperative Extension farm advisor. 

The findings have shown great promise for recharging groundwater without negatively impacting alfalfa yield but may diminish quality. “You could do recharge in winter and then turn the water off completely and still get a cutting or two of alfalfa before the summer,” said Bali, a UCCE irrigation water management specialist.

The UC ANR researchers harvested the alfalfa plots to plots to evaluate yield and quality. Photo by Nick Clark

Like Bali, Clark thinks alfalfa growers could use their fields for recharging groundwater while taking steps to limit loss of crop value. 

“We did find that the practice of recharging groundwater in alfalfa fields can have a negative impact on the feed quality of the alfalfa when first harvested after the flooding,” Clark said.

“One big recommendation we have is that the alfalfa fields should be in their later years of production so if something disastrous happens, there is not so huge of investment return lost,” said Clark. “There is current research being conducted by UC Cooperative Extension specialists Dan Putnam and Khaled Bali examining practical solutions on the farm level that growers can implement to minimize the risk of damage to alfalfa when also flooding fields for groundwater recharge.”

Clark emphasized that farmers face incredibly complex water-management issues today. The drivers that influence their decisions reach far beyond the farm, so he collaborates with UC Davis professor Helen Dahlke, who studies integrated hydrologic sciences.

“It requires an approach from multiple disciplines to address that complexity,” he said. “Helen brings hydrological expertise, while I can focus on agronomy. So the information we provide is more holistic and relevant on a larger scale, but still practical and applicable for farmers.” 

Grower input on the research findings has been critical to their success. “With their feedback, we were able to reform some of the project methodologies to achieve results that were even more relevant to the local conditions,” said Clark.  

With the prolonged drought, innovations in groundwater recharge are becoming more crucial. Future research will continue to focus on how growers can use their land in multifaceted ways to improve California's water sustainability far into the future. 

Posted on Monday, December 6, 2021 at 10:42 AM
  • Author: Madison Sankovitz, student intern
Tags: Alfalfa (21), groundwater (23), Helen Dahlke (9), Khaled Bali (14), Nick Clark (3)
Focus Area Tags: Agriculture, Natural Resources

Citrus threat target of $7 million multistate research project

This tree in Florida shows symptoms of huanglongbing (HLB) disease, including a thinning canopy and fruits that fall easily. HLB has devastated the citrus industry in Florida, and poses a threat to California growers. Photo: UC Regents

UC ANR part of team led by Texas A&M AgriLife combating huanglongbing disease

Citrus greening, or huanglongbing disease (HLB), is the most devastating disease for orange and grapefruit trees in the U.S. Prevention and treatment methods have proven elusive, and a definitive cure does not exist.

Since HLB was detected in Florida in 2005, Florida's citrus production has fallen by 80%. Although there have been no HLB positive trees detected in commercial groves in California, more than 2,700 HLB positive trees have been detected on residential properties in the greater Los Angeles region.

“It is likely only a matter of time when the disease will spread to commercial fields, so our strategy in California is to try to eradicate the insect vector of the disease, Asian citrus psyllid,” said Greg Douhan, University of California Cooperative Extension citrus advisor for Tulare, Fresno and Madera counties.

Now, a public-private collaborative effort across Texas, California, Florida and Indiana will draw on prior successes in research and innovation to advance new, environmentally friendly and commercially viable control strategies for huanglongbing.

Efforts to get ahead of HLB in California have focused on the eradication of the disease's insect vector, Asian citrus psyllid. Photo: UC Regents

Led by scientists from Texas A&M AgriLife Research, the team includes three UC Agriculture and Natural Resources experts: Douhan; Sonia Rios, UCCE subtropical horticulture advisor for Riverside and San Diego counties; and Ben Faber, UCCE advisor for Ventura, Santa Barbara and San Luis Obispo counties.

$7 million USDA project

The $7 million, four-year AgriLife Research project is part of an $11 million suite of grants from the U.S. Department of Agriculture National Institute of Food and Agriculture, NIFA, to combat HLB. The coordinated agricultural project is also a NIFA Center of Excellence.

“Through multistate, interdisciplinary collaborations among universities, regulatory affairs consultants, state and federal agencies, and the citrus industry, we will pursue advanced testing and commercialization of promising therapies and extend outcomes to stakeholders,” said lead investigator Kranthi Mandadi, an AgriLife Research scientist at Weslaco and associate professor in the Department of Plant Pathology and Microbiology at the Texas A&M College of Agriculture and Life Sciences.

The UC ANR members of this collaboration will be responsible for sharing findings from the research with local citrus growers across Southern California, the desert region, the coastal region and the San Joaquin Valley.

“In addition to the ground-breaking research that will be taking place, this project will also help us continue to generate awareness and outreach and share the advancements taking place in the research that is currently being done to help protect California's citrus industry,” said Rios, the project's lead principal investigator in California.

Other institutions on the team include Texas A&M University-Kingsville Citrus CenterUniversity of FloridaSouthern Gardens CitrusPurdue University and USDA Agricultural Research Service.  

Kranthi Mandadi, Texas A&M AgriLife Research scientist, is the lead investigator on a multistate HLB project that includes UC ANR's Sonia Rios, Greg Douhan and Ben Faber. Photo: Texas A&M AgriLife

“This collaboration is an inspiring example of how research, industry, extension and outreach can create solutions that benefit everyone,” said Patrick J. Stover, vice chancellor of Texas A&M AgriLife, dean of the Texas A&M College of Agriculture and Life Sciences and director of Texas A&M AgriLife Research.  

HLB solutions must overcome known challenges

An effective HLB treatment must avoid numerous pitfalls, Mandadi explained.

One major problem is getting a treatment to the infected inner parts of the tree. The disease-causing bacteria only infect a network of cells called the phloem, which distributes nutrients throughout a tree. Starved of nutrients, infected trees bear low-quality fruits and have shortened lifespans.

Treatments must reach the phloem to kill the bacteria. So, spraying treatments on leaves has little chance of success because citrus leaves' waxy coating usually prevents the treatments from penetrating.

Second, while the bacteria thrive in phloem, they do not grow in a petri dish. Until recently, scientists wishing to test treatments could only do so in living trees, in a slow and laborious process.

Third, orange and grapefruit trees are quite susceptible to the disease-causing bacteria and do not build immunity on their own. Strict quarantines are in place. Treatments must be tested in groves that are already infected.

Two types of potential HLB therapies will be tested using novel technologies

The teams will be working to advance two main types of treatment, employing technologies they've developed in the past to overcome the problems mentioned above.

First, a few years ago, Mandadi and his colleagues discovered a way to propagate the HLB-causing bacteria in the lab. This method involves growing the bacteria in tiny, root-like structures developed from infected trees. The team will use this so-called “hairy roots” method to screen treatments much faster than would be possible in citrus trees.

The "hairy roots" method, in which researchers grow HLB-causing bacteria in tiny, root-like structures developed from infected trees, will speed the process of screening treatments. Photo: Texas A&M AgriLife
In these hairy roots, the team will test short chains of amino acids – peptides – that make spinach naturally resistant to HLB. After initial testing, the most promising spinach peptides will undergo testing in field trees. To get these peptides to the phloem of a tree, their gene sequences will be engineered into a special, benign citrus tristeza virus vector developed at the University of Florida. The citrus tristeza virus naturally resides in the phloem and can deliver the peptides where they can be effective.

“Even though a particular peptide may have efficacy in the lab, we won't know if it will be expressed in sufficient levels in a tree and for enough time to kill the bacteria,” Mandadi said. “Viruses are smart, and sometimes they throw the peptide out. Field trials are crucial.”

The second type of treatment to undergo testing is synthetic or naturally occurring small molecules that may kill HLB-causing bacteria. Again, Mandadi's team will screen the molecules in hairy roots. A multistate team will further test the efficacy of the most promising molecules by injecting them into trunks of infected trees in the field.

A feasible HLB treatment is effective and profitable

Another hurdle to overcome is ensuring that growers and consumers accept the products the team develops.

“We have to convince producers that the use of therapies is profitable and consumers that the fruit from treated trees would be safe to eat,” Mandadi said.

A side-by-side comparison shows the difference between a healthy grapefruit and one affected by HLB. Photo: Texas A&M AgriLife

Therefore, a multistate economics and marketing team will conduct studies to determine the extent of economic benefits to citrus growers. In addition, a multistate extension and outreach team will use diverse outlets to disseminate project information to stakeholders. This team will also survey growers to gauge how likely they are to try the treatments.

“The research team will be informed by those surveys,” Mandadi said. “We will also engage a project advisory board of representatives from academia, universities, state and federal agencies, industry, and growers. While we are doing the science, the advisory board will provide guidance on both the technical and practical aspects of the project.”

Project team members:

—Kranthi Mandadi, Texas A&M AgriLife Research.     

—Mike Irey, Southern Gardens Citrus, Florida.    

—Choaa El-Mohtar, University of Florida Institute of Food and Agricultural Sciences, Citrus Research and Education Center.

—Ray Yokomi, USDA-Agricultural Research Service, Parlier, California.

—Ute Albrecht, University of Florida IFAS Southwest Florida Research and Education Center.   

—Veronica Ancona, Texas A&M University-Kingsville Citrus Center.

—Freddy Ibanez-Carrasco, Texas A&M AgriLife Research, Department of Entomology, Weslaco.

—Sonia Irigoyen, AgriLife Research, Texas A&M AgriLife Research and Extension Center at Weslaco.

—Ariel Singerman, University of Florida IFAS Citrus Research and Education Center.

—Jinha Jung, Purdue University, Indiana.     

—Juan Enciso, Texas A&M AgriLife Research, Department of Biological and Agricultural Engineering, Weslaco.

—Samuel Zapata, Texas A&M AgriLife Extension, Department of Agricultural Economics, Weslaco.

—Olufemi Alabi, Texas A&M AgriLife Extension, Department of Plant Pathology and Microbiology, Weslaco.

—Sonia Rios, University of California Cooperative Extension, Riverside and San Diego counties.

—Ben Faber, University of California Cooperative Extension, Ventura, Santa Barbara and San Luis Obispo counties.

—Greg Douhan, University of California Cooperative Extension, Tulare, Fresno and Madera counties.


Posted on Friday, December 3, 2021 at 8:17 AM
  • Author: Olga Kuchment, Communications Specialist, Texas A&M AgriLife
  • Author: Mike Hsu
Tags: A&M (1), Ben Faber (10), citrus (31), citrus disease (1), citrus greening (4), Greg Douhan (3), HLB (6), huanglongbing (33), NIFA (1), Sonia Rios (1), USDA (17)
Focus Area Tags: Agriculture, Food, Innovation, Pest Management

Get in on GivingTuesday Nov. 30

UC Agriculture and Natural Resources connects the power of UC research in agriculture, natural resources, nutrition and youth development with local communities to improve the lives of all Californians.

Join us on Tuesday, Nov. 30, for GivingTuesday, a global day of giving that harnesses the collective power of individuals to celebrate generosity worldwide. In 2020, UC ANR raised nearly $200,000 in online donations benefiting participating programs, research and endowments across the state.

Your #GivingTuesday gift helps us address important issues impacting all Californians. Choose your favorite program or county to support at ucanr.edu/givingtuesday.

Then take a virtual tour of UC ANR or peruse our annual report to read about the difference we're making.

Posted on Tuesday, November 30, 2021 at 1:58 PM

Water Wizards will reach out to Bay Area kids

Igor Lacan, UCCE environmental horticulture and urban forestry advisor, scoops aquatic life from a stream on Elkus Ranch.

UC Davis and UC ANR receive $10 million for water research and education; Bay Area children will be invited to learn about water's importance to life

A new University of California Cooperative Extension program will teach Bay Area schoolchildren about water through hands-on activities. Funded by a $565,000 USDA National Institute of Food and Agriculture grant, the education program is part of a larger research project led by UC Davis Professor Isaya Kisekka, in partnership with multiple institutions and ecologists, to sustain irrigated agriculture while improving groundwater quantity and quality in the Southwest under a changing climate.

Water Wizards, a UCCE-led youth project, will include opportunities for students of color to meet with diverse scientists and imagine career possibilities in science, technology, education and math (STEM).

“As a grandparent myself, I'm proud to support the University of California Cooperative Extension's Water Wizards program,” said Nate Miley, Alameda County Board of Supervisors vice president. “This exciting, hands-on learning experience teaches students the importance of water conservation while encouraging good stewardship of our environment.”

Lacan shows children visiting Elkus Ranch in 2017 how to identify insects scooped from the stream. Photo by Evett Kilmartin

With Water Wizards, students will explore STEM solutions to water scarcity, water quality, and climate change. Students will also take a field trip to UC Agriculture and Natural Resources' Elkus Ranch Environmental Education Center in Half Moon Bay for hands-on learning. 

“I am incredibly ‘pumped' for the Water Wizards program to inspire Bay Area BIPOC [Black, Indigenous and people of color] youth to pursue STEM through connections with water, food and the environment as well as receive mentorship from UC Cooperative Extension scientists,” said Mallika Arudi Nocco, an assistant professor of Cooperative Extension in soil-plant-water relations at UC Davis.

“We want to create an opportunity for urban kids in the Bay Area to experience different surroundings and literally get their feet wet,” said Frank McPherson, director of UC Cooperative Extension in the Bay Area counties of Alameda, Contra Costa, San Mateo and San Francisco. “We expect our hands-on, research-based, experiential learning approach to STEM will stimulate the interest of students who are Black, Indigenous and people of color.”   

He envisions students from Hayward and Oakland dipping jars into a gurgling stream that flows through the rolling green hills and canyons of the 125-acre Elkus Ranch so educators can show them some of the organisms that live in the water as part of the natural ecosystem.

During a 2018 afterschool program in Sacramento County, UC Cooperative Extension specialist Sam Sandoval Solis demonstrates a groundwater model. Photo by Marianne Bird

“We will collaborate with school districts, teachers and staff on an 11-week program designed to spark environmental learning, increase STEM knowledge and broaden students' understanding of water, sustainable agriculture and conservation,” said McPherson. 

Initially UC Cooperative Extension will be reaching out to Bay Area students with a focus on 7th through 10th graders in Alameda County schools with high populations of Black, Latinx and other students of color.

“Hayward Unified is excited to partner with UC ANR on the Water Wizards Youth Program to provide students with hands-on learning experiences that encourage inquiry, a provide chance to visit a local Water Education Center, and build environmental literacy for students to take action on water issues in the community,” said Nancy Wright, an elementary science teacher with the Alameda County Office of Education.

The program is designed to provide experiential learning to BIPOC students and encourage them to build upon their own knowledge and skills, McPherson said. “We teach them that water is a valuable and limited resource so that they can make informed decisions,” he explained. “The program also includes a service-learning project that combines learning objectives with community service.” 

To adapt Water Wizards for the Bay Area, McPherson said they are working with Marianne Bird, the UC 4-H youth development advisor who developed Water Wizards for Sacramento-area children.

Under Bird's supervision, Capitol Corridor Water Wizards engages about 400 youth each year, predominately at schools in lower-income neighborhoods, where at least 50% of students are eligible for free or reduced-price meals. The Water Wizard participants learn about water cycles, watersheds, salinity, water density and water issues and begin to understand how people, plants and animals depend on water.

McPherson said the NIFA grant will support delivery of the pilot water education program with Alameda County schools. He is currently working to secure funding from other sources to expand Water Wizards to more schools in the Bay Area. 

Posted on Monday, November 29, 2021 at 1:17 PM
Focus Area Tags: Natural Resources

UC Master Food Preservers turn food scraps into gifts Dec. 1

Strawberry vinaigrette and many other food products can be made from discarded fruit, according to UCCE Master Food Preservers.

Free online class offers recipes for using food scraps, answers questions about food preservation

“Putting food in our bellies instead of landfills is good for the planet,” said Sue Mosbacher, University of California Master Food Preserver Program coordinator. In landfills, decaying food releases methane, a greenhouse gas that contributes to climate change.

“We can reduce food waste and save money by creating new foods from food scraps,” Mosbacher said. “Instead of throwing away a lemon peel after squeezing out the juice, use the lemon zest to make lemon curd or citrus salt. They make wonderful homemade gifts for the holidays.”

UC Cooperative Extension Master Food Preservers, a program of UC Agriculture and Natural Resources, provides ideas for using leftovers and advice for safely preserving food.

On Dec. 1, 6:30 to 7:30 p.m., UCCE Master Food Preserver volunteers of Amador and Calaveras counties will host a free online class to show samples of apple honey, citrus salt, strawberry vinaigrette, sugared walnuts and lemon curd. Recipes will be emailed to participants. 

Apple fruit honey can be made from apple peel.

“Many of these gifts are inexpensive to make because you're using food scraps – such as lemon rind or apple peel – and a few other ingredients. You can put the citrus salt in jars you've saved,” Mosbacher said. “It is easy to make and there's no special equipment needed.”

After the “show and tell” session, the UCCE Master Food Preserver volunteers will answer participants' questions about freezing, dehydrating and canning foods and food safety.

Because the class is online, anyone can participate, regardless of their location. Register for the one-hour Zoom workshop at https://mfp.ucanr.edu/Events/?calitem=516566

The UCCE Master Food Preserver Program extends UC research-based information about home food safety and preservation to the public throughout the year. UCCE Master Food Preserver volunteers are located in 19 counties of California, most recently certifying volunteers in Modoc County, where they are offering pressure canner testing.

UCCE Master Food Preserver volunteers host monthly workshops on the first Wednesday of each month, with hosting duties rotating between Sacramento, El Dorado, Amador and Calaveras counties.

For 2022, the UCCE Master Food Preservers of Sacramento County are planning to offer the following workshops via Zoom:

  • Jan. 19 – Citrus for Super Bowl
  • Feb. 16 – Dehydration for Soups 
  • March 16 – Soups & Roots
  • April 20 – “Night of Fermenting” Cheese/Yogurt/Sauerkraut 
  • May 18 – Jams & Jellies
  • June 15 – “Ready for BBQ Season” Condiments & Beverages
  • July 20 - Red, White & Blue
  • Aug. 17 – “Tomato Mania” Salsas, Sauces & Peppers
  • Sept. 21 – Sausages & Mustards
  • Oct. 19 – “Apples, Pears & Persimmons Oh My”
  • Nov. 16 – Sides Dishes for your Holiday Dinner
  • Dec. 21 – Quick Gifts

To sign up for any of the workshops above, visit https://sacmfp.ucanr.edu

To find other upcoming UCCE Master Food Preserver Program events, visit https://mfp.ucanr.edu/Events. To find a program in your county, visit https://mfp.ucanr.edu/Contact/Find_a_Program.

Resources for preserving food and more information about the UCCE Master Food Preserver Program are available at https://mfp.ucanr.edu.

Posted on Tuesday, November 23, 2021 at 11:14 AM
Focus Area Tags: Food

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