Posts Tagged: Organic
Burrowing rodents can cause extensive and expensive damage to orchards and crop fields. To manage the pests without chemicals used on conventional farms, organic growers can consult a new publication from UC Agriculture and Natural Resources scientists.
“Burrowing Rodents: Developing a Management Plan for Organic Agriculture in California” outlines management within organically acceptable methods using an integrated pest management approach.
California ground squirrels, pocket gophers and meadow voles are the three most common species that cause damage. Squirrels chew on seedlings, fruit and nuts, killing young trees and reducing crop yields. In addition to plants, ground squirrels, pocket gophers and voles can chew on irrigation lines, and their burrow systems can channel water away from plants and erode the soil. The holes and mounds created by burrowing rodents pose hazards to farmworkers and farm machinery.
This publication helps growers identify the rodent species on their properties, their life cycles and tools available to control them.
“Growers can read about how to effectively select and set a range of traps for burrowing rodents,” said co-author Margaret Lloyd, UC Cooperative Extension small farms advisor for the Capitol Corridor. “Traps are an important tool for organic management, but maximizing control comes from integrating knowledge. Here we present information about rodent biology, trap efficacy, biocontrol, habitat management, plant protection and other approaches to collectively manage the pest problem.”
In the publication, Lloyd and Roger Baldwin, UC Cooperative Extension wildlife specialist in the UC Davis Department of Wildlife, Fish and Conservation Biology, review the effectiveness of commercially available traps – where to place the traps, whether to use attractants, and methods of euthanizing the animals.
They also offer cultural techniques for deterring rodents such as flooding fields and deep ripping soil to destroy burrow systems. Crops for orchard floors or cover cropping can be selected and managed to minimize habitat that protects and encourages gophers and voles.
For biological control, they suggest barn owls, raptors and snakes might be able to assist, but warn growers that predators alone will not be able to eat enough of the rodents to reduce the high populations to tolerable levels for many growers.
“Effective management will rely on a suite of tools,” said Baldwin.
The 15-page publication is available for free download at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8688.
Historically, chickens were not a rare sight on farms, where they contributed to soil fertility as they freely pecked and scratched around vegetable gardens and crop land. Now, UC Cooperative Extension specialists have launched a research project to quantify the potential for chickens to be part of safe and sustainable commercial organic vegetable production.
“It's not a new idea. A lot of farmers are trying this kind of thing,” said UC Davis International Agriculture and Development graduate student Faye Duan, the project coordinator. “But there is currently little scientific information for using chickens on a bigger scale, especially in terms of food safety concerns.”
The California trial is part of a national effort to diversify organic vegetable farms with chickens. Last year, the USDA-funded study was launched by Iowa State University horticulture professor Ajay Nair. The project also includes UC Cooperative Extension specialists Maurice Pitesky and Jeff Mitchell, based at UC Davis, and University of Kentucky entomology professor David Gonthier.
In the trials, chickens are introduced as part of a rotation that includes cover crops and a variety of vegetable crops. In California, chickens were placed on research plots in April following a winter cover crop of vetch, peas, fava beans and oat grass.
“We don't let the chickens run around the field,” Duan said. “We keep them inside of chicken tractors to protect them from predators.”
Twenty-nine birds live in each 50-square-foot tractor, essentially a floorless chicken coop on wheels. The tractors, built by UC Davis students Mallory Phillips and Trevor Krivens, are wood frames covered with mesh and plywood. Each day, the tractors are moved to a different part of the plot, where the birds can graze on cover crop residue and deposit manure. Adjusting to the daily move took time, Duan said.
“The first day, the chickens were confused. We had to go slowly. It's a learning process for the chickens and us,” she said. “But now, the chickens are excited to move to a new spot where they have fresh food to graze on.”
After 24 days on pasture, the chickens will be removed, and become part of the project's meat study.
“We have broiler chickens that are raised for meat,” Duan said. “Some people believe chickens that graze and eat grass taste better and are more nutritious. It will be part of the study to look at the chicken's meat quality.”
Once the chickens have done their part on the research plots, vegetables are planted amid the leftover cover crop residue and chicken manure. This summer, the experiment in California will grow processing tomatoes. Subsequently, melons, eggplant, spinach and broccoli will be part of the vegetable rotation in California or the other states involved in the project. Other replications of the trial will have the chickens immediately follow the vegetable harvest so they can graze on the crop leftovers before the cover crop is planted. Comparing the soil health, fertilizer needs, chicken quality and other factors will help the scientists optimize the rotation.
“Vegetable yield will be an important indicator of success,” Duan said.
Soil samples will be tested to determine the presence or absence of Salmonella bacteria after the chickens have been removed, said Pitesky, a poultry specialist and a project lead. Salmonella is a bacterium that can be part of poultry's microbiome. If the bacteria contaminates human food, it can cause illness.
“Since Salmonella lives in the chicken gastrointestinal system, when it gets into the soil, it will eventually be out-competed by bacteria more adapted to soil than the gut of a chicken,” Pitesky said. “There are many different types of Salmonella, and only a select few found in birds are the ones that are harmful to humans. Nevertheless, it is very important to test and use various practices to mitigate the presence of Salmonella on land that will be used for crop production following poultry.”
Early results of soil tests in Iowa and Kentucky detected Salmonella in the soil where chickens grazed, however, the bacteria disappeared very quickly.
(Editor's Note: Watch the April 3rd celebration of the Life and Legacy of Wittko Franke at https://youtu.be/HHQzvaJB33U.) “Nature is...
Renowned organic chemist Wittko Francke met with UC Davis researchers following his Dec. 8, 2010 presentation. From left are chemical ecologist Zain Syed of the Walter Leal lab; chemical ecologist and forest entomologist Steve Seybold (1959-2019) of the USDA Forest Service, Pacific Southwest Research Station, and the UC Davis Department of Entomology and Nematology; and UC Davis chemical ecologist Walter Leal. (Photo by Kathy Keatley Garvey)
UC Davis distinguished professor Walter Leal is organizing the symposium to celebrate the life and legacy of a giant in the chemical ecology world.
The safety of the weed killer glyphosate, the active ingredient in some well-known Roundup products, has been the subject of attention recently because of lawsuits that connected the chemical to cancer in humans.
Based on extensive scientific research, U.S. regulatory agencies have not banned glyphosate, but the publicity has increased interest in alternatives to the herbicide, which is the most widely used pesticide in the world.
“Everybody is really clamoring for information,” said area integrated pest management advisor Karey Windbiel-Rojas. “Efficacy of organic herbicides is one of the most popular talks I am giving at the moment.”
Windbiel-Rojas and former UC Cooperative Extension environmental horticulture advisor Maggie Reiter launched research projects in 2019 to help fill knowledge gaps on the effectiveness of organic herbicides in urban landscapes – such as lawns, golf courses, parks, cemeteries and school grounds. (Reiter has since taken an extension educator position at the University of Minnesota.)
Organic herbicides are pesticides made of compounds that occur in nature; and synthetic herbicides are compounds developed in laboratories. While both can be more toxic or less toxic to people and the environment, some people prefer using organic methods or chemicals.
On a small scale, a variety of organic solutions to weeds are readily available – such as hand pulling, hoeing and mulching. For larger jobs, professional landscape managers prefer applying an herbicide and look to UC Cooperative Extension scientists to know how well different options will work.
Reiter set up a study on at Ridge Creek Golf Course in Dinuba, and Windbiel-Rojas set up a study on a landscaped area with a mix of grasses and weeds in a parking lot at Sacramento State University.
In the Dinuba experiment, Reiter applied organic herbicides on 25-square-foot plots in four replications. The active ingredients of the organic herbicides included such naturally occurring chemicals as citric acid, clove oil, orange oil, acetic acid (vinegar four times stronger than that found in most home pantries), soaps, and caprylic acid, which comes from coconut and palm kernel oils.
The plots treated with citric acid and clove oil remained as green and lush as the grass in the control areas, which hadn't been treated at all. The areas sprayed with the other organic herbicides showed significant injury two days after treatment. However, 19 days post-treatment the plots treated with caprylic acid and herbicide soaps had completely recovered. The plots treated with orange oil and acetic acid recovered after 28 days.
In the Sacramento State trial, Windbiel-Rojas used some of the same organic compounds, plus others with different natural ingredients, such cinnamon oil, pelargonic acid and ammonium nonanoate, which are drawn from fruit, vegetables and other plant sources.
Many products burned down both grasses and broad-leaf weeds after a few days, however, a couple weeks later, the weeds began to regrow or recover. In addition, some of the organic treatments are more acutely toxic to people than glyphosate.
“While organic, 20% acetic acid is very toxic to the person applying the herbicide,” Windbiel-Rojas said. “It will burn one's skin, hair and eyes so the applicator must wear more personal protective equipment than with some other herbicides. This material is also problematic to use in a public space because any bystanders could be exposed to drift during application.”
The research was published in the February 2020 issue of CAPCA Adviser Magazine. The findings of the research on organic herbicides for turfgrass are preliminary and UC IPM researchers will continue to investigate options.
Windbiel-Rojas will present “Glyphosate Alternatives and Organic Herbicides in Landscapes: Efficacy and Tradeoffs” at the Pesticide Applicators Professional Association Zoom webinar Dec. 2. View the agenda here: https://www.papaseminars.com/uploads/Seminars/11643.pdf. For more information and the registration link, visit https://www.papaseminars.com/seminars.
The newly appointed Presidential Director for the Clif Bar Endowed Organic Agriculture Institute, Houston Wilson, has already initiated a needs assessment of organic agriculture in California, reported Lee Allen in Western Farm Press. Wilson is using surveys and focus groups to determine production needs within target commodities.
“Our mission will be to develop research and extension for organic production of things like tree fruits, tree nuts and raisins, commodities representing a significant portion of the entire Central Valley, but with very different cropping systems," Wilson said.
The diversity of California agriculture is represented in scale and systems - from orchards to vineyards to row crops and rice production.
"We're working on a cost-benefit analysis for commodities across the state to determine where gains can be had by developing better organic practices," Wilson said. "The argument about whether or not organic production can produce more yield is a hot topic. There are arguments that say organic can't yield as much as conventional and that may be because not that much has been invested in the organic effort compared to conventional agriculture. Metaphorically, it's like comparing a veteran player with a new kid on the team."
Price premiums for certified organic produce entice growers to convert to organic.
"Our job is to work with them, to identify and develop industry practices that make (organic production) move even more alluring," Wilson said.