- Author: Janet Byron
Conservation tillage seeks to reduce the number of times that tractors cross the field, in order to protect the soil from erosion and compaction, and save time, fuel and labor costs. Cotton crops are planted directly into stubble from the previous crop in the rotation.
In the study, conducted from 2000 to 2011 at the UC West Side Research and Extension Center in Five Points (southwest of Fresno), the number of tractor passes for a cotton-tomato rotation grown with a cover crop was reduced from 20 in the standard treatment to 13 with conservation tillage.
By the final years of the in the San Joaquin Valley study, cotton lint yields were statistically equivalent and even higher (in 2011) than with standard cultivation methods.
“The UC studies have consistently shown that conservation tillage can yield as well as standard tillage in a cotton-tomato rotation,” lead author Jeffrey P. Mitchell, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis, and co-authors wrote in California Agriculture journal.
Their study, “Conservation tillage systems for cotton advance in the San Joaquin Valley,” as well as the entire July-September 2012 issue of California Agriculture journal, can be viewed and downloaded online at: http://californiaagriculture.ucanr.edu.
Mitchell is a founder of Conservation Agriculture Systems Innovation (CASI), a diverse group of more than 1,800 farmers, industry representatives, UC and other university faculty, and members of the Natural Resources Conservation Service and other public agencies (http://ucanr.edu/CASI). CASI defines conservation tillage as a suite of cultivation practices — including no-tillage, minimum tillage, ridge tillage and strip tillage — that reduce the volume of soil disturbed and preserve crop residues in the field. Conservation tillage is common in other regions of the United States and parts of the world and is beginning to gain acceptance in California agriculture.
Technological upgrades to tillage implements have been critical to the advancement of conservation tillage systems. These include equipment that can target operations to just the plant row rather than the whole field as well as accomplish several operations at the same time.
Fuel use was reduced by 12 gallons and labor by 2 hours per acre in the conservation tillage plots. This amounted to savings of about $70 per acre in 2011 dollars.
Mitchell noted that more research is needed on the adequate development of cotton stands and the prevention of soil compaction under different conditions, but that the benefits of conservation tillage are becoming increasingly obvious. “Provided that yield performance or more importantly bottom-line profitability can be maintained and the risks associated with adopting a new tillage system are deemed reasonable, conservation tillage systems may become increasingly attractive to producers and more common in San Joaquin Valley cotton-growing areas.”
Also in the July-September 2012 issue of California Agriculture:
Agricultural burning and air quality: Southern California farmers in Imperial County regularly burn crop residues of bermudagrass in the winter and wheat stubble in the summer. A study of ambient air quality adjacent to and downwind of agricultural burning sites in the desert county found that particulate matter levels (PM2.5) were 23% higher on burn days than on no-burn days at four locations. Researchers from the California Department of Public Health also assessed community educational needs regarding agricultural burning and developed fact sheets in English and Spanish targeting the general public, schools and farmers.
The value of privately owned oak woodlands: More than 80 percent of California’s 5 million oak woodland acres are privately owned. In a survey, researchers from Spain and UC Berkeley asked private owners of California oak woodlands to place a monetary value on amenities from their land such as recreation, scenic beauty or a rural lifestyle. The technique, called “contingent valuation,” found that landowners would be willing to pay $54 per acre annually for private amenities from their land and that their willingness to pay per acre decreased as their property size increased.
Microchips for woody plants: Radio-frequency identification (RFID) tags are widely used to track books in libraries, products during manufacturing, cattle from rangeland to the slaughterhouse, inventory in retail, runners in road races and much more. These tiny microchips (often the size of a grain of rice) are now being placed in woody plants such as grapevines and orchards to monitor crop diseases, track irrigation and pesticide applications, and help prevent the theft of valuable plants. In this review, Italian researchers discuss the emerging uses of RFID technology in agriculture.
Rainfall simulators to measure erosion: In their efforts to keep Lake Tahoe clear, researchers have been studying the movement of sediments into the lake using rainfall simulators. These fairly simple machines are placed on a slope; “rain” is created over a small frame, which allows sediment in the runoff to be collected and measured. However, the lack of standardization in erosion studies using rainfall simulators may be hampering progress. Mark Grismer, professor in the Department of Land, Air and Water Resources at UC Davis, makes the case for standardized field methodologies and data analysis.
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California Agriculture is the University of California’s peer-reviewed journal of research in agricultural, natural and human resources. For a free subscription, go to: http://californiaagriculture.ucanr.edu, or write to calag@ucanr.edu.
WRITERS/EDITORS: To request a hard copy of the journal, e-mail jlbyron@ucanr.edu.
- Author: Pamela Kan-Rice
“When I started, there were about 22,000 acres, now there are more than 68,000 acres,” said Krueger, who retired July 1 as UCCE advisor in Glenn and Tehama counties and director for UCCE in Glenn County. Part of that expansion can be attributed to Krueger’s research showing how almonds and walnuts can be produced on marginal soils with high density plantings and drip irrigation.
“Bill Krueger is a great asset to our agricultural community,” said Erick Nielsen, who grows prunes and olives in Orland.
“We have enjoyed working with Bill for many years,” Nielsen said. “He has always been the kind of guy to just jump right in and help. We have appreciated his dedication to agricultural research and his knowledgeable guidance.”
Raised on a farm in Prosser, Wash., Krueger was introduced to farming by his parents, who grew Concord grapes and cherries. He earned his bachelor’s and master’s degrees in horticulture at Washington State University, then worked for a year as foreman at Mt. Adams Orchard Company in White Salmon, Wash., tending cherries, apples and pears.
In 1980, Krueger moved to California to become the UC Cooperative Extension advisor for tree crops in Glenn County.
“I’ve spent my entire career in Glenn County,” remarked Krueger, who specializes in production of almonds, walnuts, prunes and olives.
Seeking opportunities for growers to diversify their crops, Krueger and his fellow UC Cooperative Extension advisor John Edstrom planted a test plot of walnut trees at the Nickels Soil Laboratory in Arbuckle in 1986.
They set up a walnut orchard with 202 trees per acre, much closer than the 60 trees per acre of a traditional orchard. The two varieties that Krueger and Edstrom planted produce a large proportion of walnuts on lateral buds, which allows for hedgerow planting and mechanical pruning. Each year, a giant hedger with eight 38-inch saws buzzed down one side of the tree rows, cropping back branches and encouraging production. In alternate years, they pruned the opposite side of the trees. Rather than being flood irrigated as most walnut orchards, the Nickels orchard was watered and fertilized using drip irrigation.
Crop yields from the dense walnut tree plantings compensated for the marginal soils. The successful demonstration plot led to thousands of acres of walnuts being planted on similar soils.
In 1992, he added responsibility for olives in Tehama County, where the number of acres of olive trees has doubled from 4,000 acres to approximately 8,000 acres. Krueger is internationally respected for his research identifying the most effective method of chemically thinning olives to increase the size of the fruit. Chemical thinning of olives has become a common practice among Sacramento Valley table olive growers.
Over the years, he has collaborated on the development of integrated pest management practices for almonds, walnuts and prunes. In 2004, Krueger was a member of the team that California Department of Pesticide Regulation honored with its IPM innovator award for the Integrated Prune Farming Practices Program.
“Over the years he has assisted us with many different pruning trials in both our olive and prune orchards,” said Nielsen. “The last project he helped us work on was a trial for various degrees of hand pruning versus mechanical pruning in prunes. Bill has a great sense of the current market for the different crops and has always been a front-runner on moving forward with research and development projects.”
Krueger developed pruning strategies to enhance early production of prunes while developing tree structure capable of supporting heavy crop loads. He helped refine mechanical thinning to manage prune crop size, a technique developed earlier by UC researchers, and his efforts to extend this research to growers helped it become a common practice when needed.
His work, in collaboration with others, on reduced pruning of almonds has helped growers save money by reducing pruning costs.
In addition to advising growers, Krueger served a total of 13 years as director for UCCE in Glenn County, from 1996 to 2001, then resuming the helm from 2004 until his retirement.
Krueger has applied for emeritus status with UC so that he can finish up a few projects, but also looks forward to working on his own 10-acre olive orchard south of Orland during his retirement.
On Aug. 17, Krueger will be celebrating his career with friends and colleagues at Mills Orchards in Hamilton City. For details, contact Jody Samons at (530) 865-1155 or jesamons@ucdavis.edu.
- Author: Diane Nelson, (530) 752-1969, denelson@ucdavis.edu
“Mel has been a mentor and leader within the range science community his entire career,” said Ken Tate, UC Cooperative Extension specialist, who holds the Russell L. Rustici Endowed Chair in Rangeland Watershed Sciences. “Mel’s ability to see emerging issues on rangelands, and to position UC ahead of these issues, has allowed us to keep our research and extension at the forefront of rangeland management.”
When George arrived at UC Davis in 1978, he was responsible mainly for forage trials, helping ranchers keep their land productive. But George could see issues with grazing and water quality on the horizon and worked to head them off at the pass.
In the early 1990s, he spearheaded the UC Cooperative Extension Rangeland Watershed Program, which uses education and applied research to help ranchers and regulators mitigate the risk of pathogens in water runoff from rangeland. Some 80 percent of California’s water passes through or is stored on rangeland and the UC Cooperative Extension Rangeland Watershed Program has helped develop management practices that keep that water clean.
“The Rangeland Management Program has been a tremendous help in protecting open space, habitat for plants and wildlife and healthy watersheds that California rangelands provide,” says Tracy Schohr, director of the California Rangeland Conservation Coalition, a band of 100 diverse environmental, ranching and policymaking groups committed to protecting the state’s diminishing rangeland. “They educate land managers and provide the objective, accurate information we need.”
George’s research and extension has improved millions of acres of rangeland in the United States, Africa, Europe, China and beyond. In 1991, for example, George worked with Chinese researchers to develop a research site in the Tibetan Plateau of Szechwan Province, helping develop a winter feeding program for their yak herds that doubled the survival of yak calves. In 1994, George helped Albania develop grazing practices to protect new forest plantations to replace those destroyed during the transition from Communist to democratic rule.
The list goes on and on.
“Mel has a knack for taking a complicated process and making it navigable for ranchers and other land managers,” says Tate who, like George, has been based in the UC Davis Department of Plant Sciences. “He has greatly advanced both the art and science of rangeland management.”
George got into range management in a round-about way, a journey that passed through farming and animal science and was nearly cut short by a plane crash.
Farming is in George’s blood going back 15 generations, a fact he learned not too long ago when he became a genealogy buff. He was raised in the Butte County town of Gridley and was the first in his family to attend college, receiving his bachelor’s degree in animal science from California State University, Chico. During his senior year at Chico, a professor interested him in range management, which led him to Texas Tech where he received his master’s in range management in August 1969.
The Vietnam War was in progress and in October 1969, George was drafted into the U.S. Army. In November 1970, he boarded a plane bound for active duty that crashed during takeoff, killing 40 people aboard. George was severely burned.
“But I lived, and was released with a medical profile that prevented me from going to a war zone,” George says.
He was stationed at Fort Ord until the summer of 1971 when he and his wife, Gail, moved to Logan, Utah, where George earned his Ph.D. in range ecology at Utah State University. He worked nearly three years on the faculty at California Polytechnic State University, San Luis Obispo, before coming to UC Davis in 1978.
George has earned countless awards over the years, including the Outstanding Alumnus at Utah State University in 2000, the prestigious James H. Meyer Distinguished Achievement Award at UC Davis in 2007 and the College of Agriculture Distinguished Alumnus Award from Chico State University in 2008.
George will stay busy in retirement, still working on a slew of rangeland research projects under way in the UC Davis Department of Plant Sciences.
“It’s such a fascinating field because rangeland is the most complex agricultural system there is,” George says. “You have to be willing to think outside the box to manage so many moving parts, and I like that. There are so many issues on the horizon like carbon storage and protecting biodiversity.”
And even in retirement, George will do all he can to keep our rangelands healthy and sustainable for generations to come.
- Author: Jeannette E. Warnert
Aflatoxin can form on a wide variety of crops, from corn to cotton to tree nuts. Careful management practices help keep levels low, but still hundreds of thousands of pounds of pistachios are rejected each year due to the presence of aflatoxin.
UC Davis plant pathologist Themis Michailides and his team of researchers at Kearney discovered how to expose pistachio trees to the spores of a beneficial fungus that displaces the fungi that produce aflatoxin. Displacing aflatoxigenic fungi with a beneficial fungus has never before been done in tree crops.
“We’ve gotten great results,” Michailides said. “The reduction in aflatoxin contaminated nuts has been up to 45 percent. We anticipate higher reduction with application of the beneficial fungus for multiple years and on larger acreage.”
The new process was approved by the U.S. Environmental Protection Agency in February and the California Department of Pesticide Regulation in May, in time for 60,000 acres of the 2012 California pistachio crop to receive the innovative treatment.
“This is a big step,” Michailides said. “There will be a tremendous savings to pistachio growers by reducing rejections and the need for resorting nuts before going to market.”
Aflatoxin was discovered in the 1960s when a flock of turkeys in England died after eating contaminated feed. Aflatoxin is produced by certain strains of the fungus Aspergillus flavus, which is commonly found in soil and decaying vegetation. Aflatoxin is a resilient foe. Roasting nuts does not destroy the toxin. Other crops, such as corn and cottonseed used as animal feed, can be treated with ammonia to reduce aflatoxin, however ammonia treatment is not possible for human food, such as tree nut crops.
All shipments of pistachios are tested for aflatoxins, and are rejected in Europe if contamination exceeds 10 parts per billion and in the United States if shipments have more than 15 parts per billion.
The use of beneficial fungi to fight aflatoxin was first discovered and investigated by Peter Cotty, a USDA Agricultural Research Service plant pathologist located in the School of Plant Sciences at the University of Arizona. Cotty’s research focuses on reducing aflatoxin presence in corn and cottonseed. In collaboration with Cotty, Michailides and his colleague Mark Doster, staff research associate in the Michailides lab at Kearney, found that Aspergillus flavus 36 (AF36) can be introduced into an orchard by inoculating “dead” wheat seeds and then dispersing the seeds on the orchard floor. Dew and soil moisture spur the development of harmless spores that colonize pistachios and prevent colonization by toxigenic fungus strains.
The Kearney scientists are continuing their cooperation with USDA’s Cotty as they expand the research to almonds and figs.
“We’re conducting micro-plot experiments with the almond industry at Kearney,” Michailides. “We hope to get an experimental use permit soon to make the treatment available to almond growers.”
Michailides’ aflatoxin research was funded by USDA, the California Pistachio Research Board, the Almond Board of California and a UC Discovery Grant. The research was made possible by the involvement of cooperating pistachio growers who opened their orchards to scientists for conducting AF36 trials.
- Author: Pamela Kan-Rice
While earning a bachelor’s degree in home economics education from South Dakota State University, Johns took a summer job with South Dakota Cooperative Extension teaching at an Indian reservation.
“One of my assignments was to teach nutrition to families on the reservation,” Johns recalls. “That’s where I learned that delivering a scripted program is not always the most effective. The beauty of Cooperative Extension is having the flexibility to tailor educational programs to meet the needs of your clientele.”
Although the Brookings, S.D., native had participated in 4-H and her father was a Cooperative Extension economics specialist at South Dakota State University, Johns didn’t really know the community-based educational organization until she began working for UC Cooperative Extension in 1974 as an advisor for Plumas, Sierra, Lassen and Modoc counties. She coordinated the 4-H youth development and nutrition education programs for those four counties until 1983, when she became a UCCE advisor in El Dorado and Amador counties in the same role.
In 1985, Johns transferred to San Mateo and San Francisco counties to serve an urban population as the UCCE 4-H youth development and nutrition, family and consumer sciences advisor. One of her projects was starting a school garden in Pacifica. She recruited senior citizens to teach the children how to grow vegetables. The senior citizens’ requests for guidance led her to develop TWIGS, 30 gardening and nutrition lessons for “Teams With Intergenerational Support.” Published in 1997, Johns continues to receive requests for the TWIGS curriculum. More than 3,500 copies have been sold to schools, after school programs, parks and recreation and YMCA programs, senior centers, nutrition networks and food banks in 22 states. California’s Department of Education uses TWIGS as an example of gardening curricula addressing education standards.
While serving the Bay Area, Johns earned a master’s degree in public administration with an emphasis in human resources at Notre Dame de Namur University in Belmont. In 2005, Johns was promoted to director for UCCE in San Francisco and San Mateo counties and director of Elkus Ranch, an environmental education and conference center in Half Moon Bay that provides hands-on learning experiences for San Francisco Bay Area youth. In 2011, Johns was also named director of UCCE in Santa Clara County.
In addition to promoting nutrition education and agricultural literacy through gardening, Johns has studied teen pregnancy. An article that she coauthored, “Best Practices in Teen Pregnancy Prevention,” was one of the most visited online articles of the Journal of Extension in 2005.
A founding member of the San Mateo Food Alliance System and a member of the statewide School Garden Network, Johns and nonprofit partners Hidden Villa and Collective Roots recently received a three-year grant of $173,000 per year from Sequoia Healthcare District to improve children’s health through garden-based learning.
While there have been groups who advocate for school gardens and those who promote nutrition, they haven’t always worked together in the past, says Jennifer Gabet, nutrition manager for Sequoia Healthcare District. Through a unique collaboration and development of a model teaching garden, 1, 2, 3 Let’s Grow! will emphasize growing edible plants, providing the students with fresh produce to eat and demonstrating how to prepare the fruit and vegetables they grow.
“Marilyn has been able to bring the two groups together, to see the garden as a mechanism to improve the school food environment and nutrition education,” Gabet said. “They teach science, but it doesn’t always include nutrition – discussion of the benefits of the foods grown and how students and families can include them in their diets to support their health.”
“This grant is pretty exciting,” Johns said, explaining that it incorporates nutrition education into hands-on activities for children, which is a more effective teaching method. She oversees the UC Master Gardener volunteers and UCCE nutrition educators who will be training K-12 teachers, parents and other participants at up to 34 schools on how to enhance children’s learning while gardening.
In retirement, Johns, who has been granted emeritus status, looks forward to continuing to contribute to garden-based learning as well as spending time with family and traveling for pleasure.
