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

Protect your garden when temperatures soar

When unusually hot weather is in the forecast, it's time irrigate, shade and mulch plants to protect your plants, reported Sandra Barrera in the Los Angeles Daily News

The story was prompted by a heat spike in Southern California recently, when temperatures soared above 110 degrees in many areas.

"While most plants can endure triple-digit temperatures, they suffer when heat comes on suddenly," the article said.

  • When a plant is dry, it's already stressed, so give it a good soaking before temperatures rise.
  • A patio umbrella, bed sheets or landscape shade cloth suspended on the sunny side of a plant will shade tender growth on hot days.
  • A three- to four-inch layer of mulch around plants will cool roots and hold moisture.
A patio umbrella can be used to shade plants during a heat wave. (Photo: Wendy Powers)

One of the best ways to avoid heat damaged trees and plants is by planning a garden for the climate.

"In Southern California, Sunset zones are preferred over USDA zones due to their greater accuracy," said Janet Hartin, UC Cooperative Extension environmental horticulture advisor for San Bernardino, Riverside and Los Angeles counties. 

UCCE advisor Janet Hartin with a research poster on plant water use and climate zones.
Hartin suggests consulting the California Native Plant Society's Calscape and Cal Poly San Luis Obispo's SelecTree for information on plants adapted to the climate and specific conditions, such as sun, shade, near buildings or swimming pools or in urban heat islands.

The American Horticultural Society also has a Heat Zone Map to select plants adaptable to inland and desert climates. The map has 12 zones searchable by city. Each zone designates the average number of days per year temperatures exceed 86 degrees, which is considered by the point at which most plants begin to suffer heat stress.

"The numbers are relatively conservative and many plant enthusiast experimenters are already finding that many plants - under the right conditions and a little shade - do just fine outside of their listed heat zone," Hartin said.

The American Horticultural Society's Plant Heat-Zone Map is a new tool for gardeners.

 

Posted on Friday, July 20, 2018 at 9:05 AM
Tags: heat wave (1), Janet Hartin (7)
Focus Area Tags: Yard & Garden

USDA awards UC and Karuk Tribe $1.2 million for collaborative research and education to increase tribal ecosystem resilience in a changing climate

The USDA-funded Tribal Food Security Project team includes members of the Karuk, Yurok and Klamath Tribes along with UC researchers. In front row, Jennifer Sowerwine is second from left and UCCE farm advisor Deborah Giraud is far right. Photo courtesy of Karuk Píkyav Field Institute.

As California and the nation grapple with the implications of persistent drought, devastating wildfires and other harbingers of climate change, researchers at UC Berkeley's College of Natural Resources and the Karuk Tribe are building on a decade-long partnership to learn more about stewarding native food plants in fluctuating environmental conditions. UC Berkeley and the Karuk Tribe have been awarded a $1.2 million USDA Agriculture and Food Research Initiative grant for field research, new digital data analysis tools and community skill-building aimed to increase resilience of the abundant cultural food and other plant resources – and the tribal people whose food security and health depend on them.

Jennifer Sowerwine, UC Cooperative Extension specialist at UC Berkeley and co-founder of the Karuk-UC Berkeley Collaborative, and Lisa Hillman, program manager of the Karuk Tribe's Píkyav Field Institute, will co-lead the xúus nu'éethti – we are caring for it research project.

UC Berkeley's College of Natural Resources, UC Agriculture and Natural Resources and the Karuk Department of Natural Resources will support the project with postdoctoral researchers, botany, mapping and GIS specialists, and tribal cultural practitioners and resource technicians. The San Rafael-based nonprofit Center for Digital Archaeology will help develop a new data modeling system.

Project activities include expanding the tribe's herbarium (a research archive of preserved cultural plants launched in 2016 with UC Berkeley support), developing digital tools to collect and store agroecological field data, and helping tribal community members and youth learn how to analyze the results.

“For the xúus nu'éethti – we are caring for it research project, UC ANR's Informatics and Geographic Information Systems (IGIS) team will lead hands-on workshops and consultations to build Karuk Tribal capacity to assess, monitor and make management decisions regarding the agroecosystem,” Sowerwine said. “Workshop curricula for tribal staff and community members will include GIS training, 360 photospheres and drone images, and storymapping techniques. ​IGIS will also provide technical analysis of historical land use and land cover records to support researchers' understanding of agroecological resilience over time.”

Sowerwine, right, shown cleaning tanoak mushrooms, an important cultural food, will study effects of climate change on the Karuk food system.

“We are delighted to continue our connection with UC Berkeley through this new project,” said Hillman. “Through our past collaboration on tribal food security, we strengthened a network of tribal folks knowledgeable in identifying, monitoring, harvesting, managing for and preparing the traditional foods that sustain us physically and culturally. With this new project, we aim to integrate variables such as climate change, plant pathogens and invasive species into our research and management equations, learning new skills and knowledge along the way and sharing those STEM skills with the next generation.”

The research team will assess the condition of cultural agroecosystems including foods and fibers to understand how land use, land management, and climate variables have affected ecosystem resilience. Through planning designed to maximize community input, they will develop new tools to inform land management choices at the federal, state, tribal and community levels.

All project activities will take place in the Karuk Tribe's Aboriginal Territory located in the mid-Klamath River Basin, but results from the project will be useful to other tribes and entities working toward sustainable management of cultural natural resources in an era of increasing climate variability. Findings will be shared nationwide through cooperative extension outreach services and publications.

The new project's name, xúus nu'éethti – we are caring for it, reflects the Karuk Tribe's continuing commitment to restore and enhance the co-inhabitants of its aboriginal territory whom they know to be their relations – plants, animals, fish, water, rocks and land. At the core of Karuk identity is the principle of reciprocity: one must first care for these relations in order to receive their gifts for future generations.

This work will be supported by the Agriculture and Food Research Initiative Resilient Agroecosystems in a Changing Climate Challenge Area, grant no. 2018-68002-27916 from the USDA National Institute of Food and Agriculture.

For more information, visit the Karuk – UC Berkeley Collaborative website at https://nature.berkeley.edu/karuk-collaborative

Posted on Wednesday, July 18, 2018 at 2:33 PM

Grow cover crops to attract beneficial insects, add nutrients, suppress weeds and build soil

George Washington, the father of our country, said it well when he proclaimed he grew “crops to eat and sell” and “crops to replenish the soil.”

Generations of farmers follow his footsteps.

Cover crops (also known as green manures) are plants primarily grown for the benefit of the soil rather than for crop yield. With autumn only a few months away, now's a good time to think about planting cool-season cover crop seed mixes for your farm or garden.

Cover crop in a walnut orchard, with flowers to attract beneficial insects, Yolo County, 2018.

Why grow cover crops?

The benefits of cover cropping include reduced soil erosion, adding organic matter, nutrients, and mycorrhizae to the soil, and weed and nematode suppression. Cover crops also increase nutrient retention and water infiltration. And some, such as radish, break into compacted soil layers, making it easier for the following crop's roots to develop more fully. Flowering cover crops on farms also increase beneficial insects, including bees and natural enemies, that provide pollination and pest control services in crop production.

How do cover crops benefit natural enemies?

Beneficial insects need nectar and pollen to survive and reproduce. For example, adult parasitoid wasps feed on flowers, while the parasitoid larvae prey on pests such as aphids, caterpillars, and stink bugs. Lady beetle, aka ladybugs, feed on flowers, especially during times of prey scarcity. In addition to flowers, cover crops, such as vetch and bell (fava) beans, have extra-floral nectaries or spurs at the base of the leaves. These secrete a sugary syrup that attracts beneficial insects, such as syrphid flies to control aphids.

UCCE advisor Rachael Long holding a lacewing, a beneficial insect that feeds on aphids. She is standing in a cover crop in a walnut orchard. (Photo: California Farm Bureau)

Insectary cover crop seed mixes.

Winter mixes that attract beneficial insects (aka Insectary Plants) and fix nitrogen include bell beans, clovers, field peas, and vetch. Other insectary plants to add to a cover crop mix include forbs such as baby blue eyes, poppies, phacelia, purple Chinese houses, sweet alyssum, and tidy tips. Small grains (triticale, barley, and rye) are good pollen sources for beneficial insects. It's a good idea to order insectary cover crop mixes from local sources to avoid potential introduction of non-native forb-type plants from other areas.

Cover crops to perhaps avoid in some crop rotations.

Avoid cover crop species that host arthropod pests or plant pathogens that can damage nearby crops. For example, bell beans are a key host for tomato spotted wilt virus vectored by thrips insects, UC IPM. Mustards attract beneficial insects, but are significant hosts for pests such as stink bugs, cucumber beetles, flea beetles, and lygus bugs. Alfalfa has extra-floral nectaries, but is not a recommended insectary plant because it hosts pathogens, including alfalfa mosaic virus that infects a number of crops, including tomatoes (UC IPM).

How important are floral resources for natural enemies?  

In a 1998 research article, Beneficial insects move from flowering plants to nearby crops, published in California Agriculture journal, I pointed out that beneficial insects extensively use flowering cover crops. In a mark-and-recapture study in an almond orchard with a cover crop, 80 percent of the syrphid flies and 40 percent of the lacewings (both aphid feeders) trapped in the trees fed on flowers and extra-floral resources that the insectary plants provided, as did 10 percent of the parasitoid wasps, which prey on peach twig borer.

Ladybugs primarily feed on aphids, but they will also feed on floral resources during times of prey scarcity.

Balancing multiple needs of cover crops.

Note that legumes need to be mowed or disked prior to full bloom for maximum nitrogen fixation, limiting floral resources. To favor beneficial insects, don't mow or disk all of your cover crop at once; instead, leave occasional strips of flowering plants on your farm. Beneficial insects will find the flowers, as they move around (at least 600 feet for many natural enemies and over a mile for bees). If frost is a concern in your orchard, consider planting strips of low-growing insectary plants, such as tidy tips and other forbs listed above. Be sure to select seed mixes that work with surrounding crops.

George Washington used cover crops to replenish the soil; they're also good for the soul when you savor the benefits, especially all the flowers and beneficial insects attracted to them. Why not play a game of “I Spy” in your cover crop and see if you can find a bumble bee or one of the myriad of natural enemies featured in the UC IPM poster, Meet the Beneficials

 

Multiple benefits of cover crops. (Diagram: Sustainable Agriculture Research and Education Program)

Additional reading

Flowering cover crops support wild bees and a regional sustainability agenda, part of the June 2018 research update in California Agriculture journal.

UC ANR publications on cover crops:

Cover crops for California Agriculture

Cover Cropping for Vegetable Production

Cover Cropping and Conservation Tillage in California Processing Tomatoes

Small Grain Cover Crops

Cowpea Production: Sample Costs and Benefits as a Summer Cover Crop

Cover Cropping in Vineyards: A Grower's Handbook

Cover Crops for Walnut Orchards

Posted on Tuesday, July 17, 2018 at 8:35 AM
Focus Area Tags: Agriculture

Horse country is often in wildfire-prone areas

A population of 700,000 horses call California home and many of them live in areas susceptible to wildfire. UC Cooperative Extension forest and fire advisor Kate Wilkin says says landowners can take advantage of equine grazing habits - eating down to the nub - to create a fire safety zone, reported Denise Steffanus in the Paulick Report.

“Having heavy grazing around your structures and then feathering it out as you go farther away from the structures is one way to protect the property,” Wilkin said. “Of course, you want to be careful not to destroy that forage by overgrazing that will cause erosion.”

Just like all rural residents, horse owners should establish a defensible safety zone around structures, including houses, barns, arenas and other outbuildings. Trees should be thinned to create a 15-foot gap between tree tops and shrubbery cleared so it won't ladder fire from the ground to the canopy.

Wilkin said a larger safety zone can serve as an oasis for horses during a wildfire. 

“For a lot of fires, if you have an irrigated pasture and you can open the gate so the horses can leave if they need to, they will often be OK,” Wilkin said. “Ultimately, you want it to be a large area … it could be an area about half-mile in diameter, and it needs to be that large to keep the heat from affecting your lungs and your horse's lungs. … You can have trees if they are widely spaced and don't have ‘ladder fuel' around them. Then you can have shade on the property but still be more fire safe.”

Wilkin added that farm owners should not rely on a body of water as a firebreak.

“An ember can travel a mile or more during a wildfire,” she said. “While a creek or a larger body of water can slow a fire down, if there are winds and high temperatures, the fire is still going to cross it.”

UCCE forest and fire advisor Kate Wilkin examines a tree with an old fire scar.
Posted on Thursday, July 12, 2018 at 12:55 PM
Tags: Kate Wilkin (6), wildfire (120)
Focus Area Tags: Environment

College students to build apple-picking robots in ASABE competition

For the 2018 ASABE Student Robotics Challenge, teams will simulate the mechanical harvest and storage of apples.

Nineteen teams of college students from top universities in the U.S., Canada and China will compete to build robots to mechanize farm work at the American Society of Agricultural and Biological Engineers Annual International Meeting in Detroit.

The 2018 ASABE Student Robotics Challenge, being organized by Alireza Pourreza, University of California Cooperative Extension agricultural mechanization specialist, will be held on July 31.

“The labor availability for agriculture is decreasing while the need for more food is increasing to feed the growing world population,” said Pourreza, who is based in the UC Davis Department of Biological and Agricultural Engineering. “So agriculture should switch to technologies that are less labor-dependent, such as using more robots, to overcome this challenge.”

Ali Pourreza, shown flying a drone to collect crop data, is organizing the 2018 ASABE Student Robotics Challenge.

The ASABE Student Robotics Challenge provides an opportunity for undergraduate and graduate students to demonstrate their knowledge and skills of robotics in agriculture.

“The goal of this event is to encourage young agricultural engineers to get involved in building robots for agricultural applications and to get experienced as the next generation of farmers,” Pourreza said.

The challenge will be to simulate the harvest and storage of apples, a crop commercially grown in several states. The students will design and operate robots that will autonomously harvest “apples” on field that measures 8 feet by 8 feet. The robots will harvest eight mature apples (red ping-pong balls), remove and dispose of eight diseased or rotten apples (blue ping-pong balls) and leave eight immature apples (green ping-pong balls) on the tree.

This year, the competitors are being divided into a beginner division and an advanced division.

Beginner Teams

California Polytechnic State University        Green and Gold Mustangs
China Agricultural College                          China Ag, Beginners
McGill University                                       We Are Groots
Purdue                                                     ABE Robotics
Purdue                                                     Harvestiers
Texas A&M                                               Texas A&M
University of California Merced                   Bobcats
University of Nebraska Lincoln                    HuskerBots 2
University of Nebraska Lincoln                    HuskerBots3
University of Wisconsin River Falls               Falcon Robotics
Zhejiang University                                    ZJU team 1
Zhejiang University                                    ZJU team 2
Clemson University                                    CARA

Advanced Teams

China Agricultural College                             Dream
McGill University                                          Agrobots
University of Georgia                                    UGA Engineers
University of California – Davis                      Ag-Botics
University of Florida                                      RoboGators
University of Nebraska Lincoln                       HuskerBots 1

The competition will be held in Cobo Center Exhibit Hall, 1 Washington Blvd., Detroit, Michigan. There will be three rounds throughout the day and each team will participate once in each round.

The 2017 robotics challenge was to simulate raspberry cane thinning, removing green canes and pruning the yellow canes.

For more information, visit the 2018 ASABE robotics competition website: https://www.asabe.org/Awards-Competitions/Student-Awards-Competitions-Scholarships/Robotics-Student-Design-Competition.

Video of 2016 competition: https://www.youtube.com/watch?v=U1ymUiCr3Mc

Video of 2017 competition: https://vimeo.com/250379863

 

Posted on Wednesday, July 11, 2018 at 2:12 PM
Focus Area Tags: Agriculture Innovation

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