- Author: Jeannette E. Warnert
- Contributor: Diane Nelson
Leslie Roche of Orosi, who served as a high school intern at Kearney, received the 2012 Shapiro Family Award for Excellence in Science for the quality of her doctorate dissertation and outstanding academic and research record at UC Davis.
"She did a bang-up job with us, continued through her undergraduate studies at UC Davis, and ended up doing a great Ph.D. dissertation," Mitchell said.
Roche's dissertation is titled, "Cattle Grazing and Provisioning of Ecosystem Services in Sierra Nevada Mountain Meadows." Working with UCCE specialist Ken Tate, Roche explored livestock grazing on U.S. Forest Service public lands and the conservation of the Yosemite toad, a sensitive species proposed for listing as endangered.
“Dr. Roche’s research was conducted in this charged political environment, filling a crucial gap in our basic understanding of toad-livestock interactions and providing direct translation for conservation of the Yosemite toad,” said Tate, Russell L. Rustici endowed chair in rangeland watershed science.
Roche is now a postdoctoral researcher in the UC Davis California Rangeland Watershed Laboratory, completing research and publications from additional projects she pursued during her doctoral program.
- Author: Jeannette E. Warnert
The San Joaquin Valley boasts many of America’s most innovative farms. However, in terms of conservation agriculture practices – such as using little or no tillage, maintaining crop residues on the soil surface, and irrigating with buried drip or overhead systems – the most important agricultural region in the world is lagging behind.
To introduce more valley farmers to the benefits of conservation agriculture practices, Conservation Agriculture Systems Innovation (CASI) produced a six-part documentary featuring California farmers, UC researchers and agency representatives. The series premieres Aug. 6 on the CASI website (http://CASI.ucanr.edu) with a 7-minute segment that lays out the theoretical principles and the scientific basis for conservation agriculture. Additional segments will be released each Monday for five weeks thereafter.
Throughout the series, viewers will meet farmers who are implementing conservation agriculture successfully and profitably on their Central Valley farms. The 6- to 10-minute episodes review the core principles and practices associated with conservation agriculture systems and provide examples of successful local adoption.
After the six-week series airs, viewers, farmers and others interested in conservation agriculture are invited to the UC West Side Research and Extension Center in Fresno County for the annual Twilight Conservation Agriculture Field Day, Sept. 13. The event, which begins at 4 p.m. and concludes when darkness falls, is free and includes a barbecue dinner. Viewers can get clarification on points from the video series and meet many of the farmers and scientists featured in the documentary, plus get a first-hand look at conservation agriculture research currently under way.
To register for the Twilight Field Day go to http://ucanr.edu/TwilightRegistration. The West Side Research and Extension Center is at 17353 W. Oakland Ave., Five Points.
“Our goal with the video series is to reach a wider audience of farmers with our research results and on-farm success stories, which show conservation agricultural practices can help make farmers more competitive and sustainable in the long run,” said Jeff Mitchell, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis.
The Conservation Agriculture Systems Innovation documentary series includes the following episodes:
Aug. 6: “Introduction to conservation agriculture” – The first video defines conservation agriculture and outlines its increasing credibility in the global context.
Aug. 13: “Maintaining crop residues” – California farmers have tended to adopt “clean cultivation” systems, but research has shown that maintenance of residues from the previous crop or a winter cover crop helps improve soil and reduces evaporation from the surface.
Aug. 20: “Conservation agriculture in tomato production systems” – These systems cut production costs, reduce dust emissions and store more carbon in the soil.
Aug. 27: “Conservation agriculture in dairy silage production systems” – Three dairy farmers committed to conservation agriculture systems in their silage production share their secrets and success.
Sep. 3: “Minimum tillage systems” – This video features examples of a number of reduced pass or ‘pass combining’ tillage systems that have been developed during the past decade.
Sep. 10: “Coupling conservation tillage with overhead irrigation” – Overhead irrigation systems, such as center pivots, are particularly useful when coupled with conservation tillage.
For more information, contact Mitchell at (559) 303-9689 or jpmitchell@ucdavis.edu.
- Author: Janet Byron
A 12-year study published in the July-September 2012 issue of the University of California’s California Agriculture journal demonstrates that cotton grown in rotation with tomatoes — using lower-impact conservation tillage — can achieve yields similar to standard cultivation methods and at lower cost.
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. Mitchell is based at the UC Kearney Agricultural Research and Extension Center.
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://CASI.ucanr.edu). 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.”
- 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: Jeannette E. Warnert
Among the conditions necessary for a cow to produce organic milk, she must eat only organic feed or browse on organic pasture for at least the previous 36 months. However, dairy producers have found that producing or sourcing organic feed – which must be grown with no synthetic fertilizers, insecticides or herbicides – is challenging. Recently organic alfalfa made up nearly 1.4 percent of U.S. alfalfa hay production, up from .5 percent in the early 2000s.
Dan Putnam, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis, an alfalfa expert, said one key obstacle for organic alfalfa producers is weed management. Putnam put together a team of alfalfa hay experts to conduct an alfalfa weed management trial at the UC Kearney Agricultural Research and Extension Center, where 10 acres are set aside to research organic production.
In 2011, Putnam; Carol Frate, UCCE advisor in Tulare County; and Shannon Mueller, UCCE advisor in Fresno County, experimented with timing seeding and early clipping to manage organic alfalfa in a weedy field.
“Alfalfa can be planted from early September all the way through the fall and winter to early spring, depending on weather patterns,” Putnam said. “Many farmers plant in late November and wait for rain to bring the crop up. Other options are irrigating the crop up in early fall or waiting till early or late spring to plant the crop. All of these strategies have implications for weed management.”
The late November planting is quite common since, compared to a September planting, it saves farmers the trouble of putting out sprinklers. However, late fall plantings failed in this experiment.
“We had a lot of weed intrusion at that point as well as cold conditions for alfalfa growth, so the stands were poor,” Putnam said.
The earlier planting also had weed intrusion, but the researchers clipped the field when the alfalfa was 10 to 12 inches high in early spring. The clipping cut back weeds that were overtopping the alfalfa, giving an advantage to the vigorous young alfalfa seedlings.
An early spring planting after tillage to destroy weeds also resulted in a good stand, but some production was lost in the first year compared with early fall plantings.
“Many growers are starting to realize that early fall (September/October) is a better time to start their alfalfa crops,” Putnam said. “With organic growers, it is even more important to pay attention to time of seeding because they have so few weed control options.”
While this research is conducted on organic alfalfa, Putnam said the results are also applicable to conventional alfalfa production, which represents more than 98 percent of California's total alfalfa crop.
“Timing has a profound effect on the first-year yield and health of the crop and its ability to compete with weeds,” he said.
Putnam, Mueller and Frate will share more information about the organic alfalfa trial during a field day at Kearney, 9240 S. Riverband Ave., Parlier, from 8 a.m. to 12 noon Sept. 5. The field day will feature the organic production trials, alfalfa variety trials, sorghum silage and nitrogen trials, and optimizing small grain yields. Other topics will be alfalfa pest management, irrigation and stand establishment.