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April 3, 2006
CONTACT: Jeannette Warnert, (559) 241-7514, jewarnert@ucdavis.edu
UC Cooperative Extension offers fresh ideas for Earth Day (April 22) news coverage
A community garden close to downtown L.A.
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-Urban gardens could be harboring harmful trace elements
-Scientists puzzled but pleased about reappearance of razor clams
-Another reason why every litter bit hurts
-Clean air and safe environment are goals of new pest management guidelines
-Slowing growth of backyard grass and trees reduces waste
-Winter cover crops clean agricultural water
Urban gardens could be harboring harmful trace elements
Planting a backyard or community garden is a great way to mark Earth Day. But there could be danger lurking in urban soils, according to UC Cooperative Extension landscape horticulture advisor Donald Hodel. “Any place subjected to human activity is likely to have elevated levels of trace elements,” he said. “While there is generally no cause for alarm, in some cases, the trace elements may accumulate and pose a health risk, especially to children.” Knowing the history of an urban garden site can reveal whether you might be gardening in contaminated soils. Being close to metal industries, auto repair or salvage yards, waste management operations, recycling industries or heavy or congested traffic may have contaminated the soil with lead, cadmium or arsenic. Unauthorized dumping of motor oil, batteries or tires on the site or the presence of buildings with old painted surfaces can also mean the soil is contaminated with harmful trace elements. Testing soils in urban gardens is a good idea if these types of activity have occurred at the site. Here are some ways to limit exposure to trace elements in garden soil:
- Dispose of all refuse in urban garden sites before planting.
- Cultivate soil deeply to dilute any contaminants at the surface.
- If possible, plant in raised beds or containers with uncontaminated soil.
- Use lots of compost and humus to amend the soil, and mulch with leaves, woodchips, hay, newspaper or other materials to reduce dust.
- Plant food, especially leafy crops like lettuce, as far as possible from streets. Use walls, fences or hedges to block auto exhaust and dust from entering the site.
- Wash hands thoroughly after working or playing in urban soils.
- Wash vegetables and fruits and peel root crops like beets, radishes and carrots before eating. Throw away outer leaves of leafy vegetables.
- Have separate gardening shoes and clothes that do not come into the house.
- Make sure children do not play in potentially contaminated areas.
For more information, contact Donald Hodel at (323) 260-3405, drhodel@ucdavis.edu. Tip by Jeannette Warnert, (559) 241-7514, jwarnert@ucop.edu.
Scientists puzzled but pleased about reappearance of razor clams
Clam digging is for many people an alluring part of the coastal experience. Humboldt County’s Clam Beach, an aptly named gentle stretch of sandy oceanfront just south of Trinidad, was for many years a popular location for clam digging. But the predominant bivalve on this beach, the Pacific razor clam, suffered a population crash shortly after the El Niño weather pattern of 1982-83. “For all intents and purposes, they disappeared,” said Pete Nelson, a California Sea Grant marine advisor in the region. “It’s only in the last few years that they’ve begun to return.” Since there have been no formal studies on the razor clam population, scientists can only speculate on the clam’s disappearance two decades ago and its sudden resurgence today. The disease Nuclear Inclusion X, which decimated populations in Washington and Oregon, is one possibility, although unproven. El Niño-induced oceanic changes may also be a factor. This spring, Nelson and his fellow marine advisor in Del Norte County, Jim Waldvogel, will begin to collect information from clam diggers themselves. A sampling station will be set up periodically on Clam Beach and on South Beach in Crescent City for the advisors to measure clam shells and start building a base of knowledge about the razor clam population. The Pacific razor clam is found from Pismo Beach in Central California to the Aleutian Islands in Alaska. For more information about the Pacific razor clam study, contact Nelson at (707) 443-8369, panelson@ucdavis.edu. Tip by John Stumbos, (530) 754-7770, jdstumbos@ucdavis.edu.
Another reason why every litter bit hurts
Removing standing water from winter storms is crucial to controlling the mosquito population, and subsequently the mosquito-borne disease West Nile virus, which last year killed 18 people in California and infected more than 900 others, says medical entomologist Gregory Lanzaro, director of the UC Mosquito Research Program and director of the UC Davis Center for Vectorborne Diseases. Female mosquitoes are looking for water to lay their eggs and they easily find it in bottles, cans, tires and other litter strewn along freeways and roads or tossed into bodies of water. Residents can do their part by emptying or turning over anything that holds water in their yards, maintaining pools and spas, adding mosquitofish to ponds and flushing out bird baths and fountains at least once a week. A female mosquito can lay about 250 eggs during her life span, which averages about a month, Lanzaro said. The Culex mosquito is the principal carrier or vector of West Nile virus. For more information, contact Lanzaro at (530) 752-5652, gclanzaro@ucdavis.edu. Tip by Kathy Keatley Garvey, (530) 754-6894, kegarvey@ucdavis.edu.
Clean air and safe environment are goals of new pest management guidelines
Shielding school children from harmful pesticides is just one of the many features in the second edition of Residential, Industrial, and Institutional Pest Control by the University of California Statewide Integrated Pest Management (IPM) Program. The book highlights new information for carrying out environmentally friendly IPM programs in and around schools and other public and private buildings. Topics include how to select appropriate pesticides, how to monitor for pests, and how to effectively use tools such as cockroach and ant baits, traps and sanitation practices. With more than 60 pests covered, the manual contains tips on using gel baits for cockroaches, removing bees from walls in buildings, applying repellants for relief from mosquitoes and ways to identify common household ants. Information on many new pests, including booklice, carpenter bees and carpenter ants, has been added to this revised edition. Chapter 2 of the book, “Using Pesticides Safely,” addresses proper application techniques and is a helpful reference for applicators trying to comply with proposed regulations to protect themselves and others. The new publication is Volume 2 in the Pesticide Application Compendium series, a six-book collection for anyone who uses pesticides, supervises their use or instructs others in pesticide use. For more information, visit the UC IPM Web site at http://www.ipm.ucdavis.edu/IPMPROJECT/ADS/manual_riipestcontrol.html. Tip by Stephanie Klunk, (530) 754-6724, sjklunk@ucdavis.edu.
Slowing growth of backyard grass and trees reduces waste
Most communities have programs for recycling lawn clippings and tree prunings. Rather than sending green waste to landfills, UC Cooperative Extension experts suggest managing the landscape to reduce the amount of green waste grown in the first place. Mindful irrigation, fertilization and pruning techniques cut back extra green growth without sacrificing aesthetic appeal, according to San Bernardino County UCCE environmental horticulture advisor Janet Hartin. Hartin and two colleagues wrote a 15-page publication that explains how to reduce lawn clippings and tree prunings. The document, for example, suggests homeowners measure sprinkler output using small, flat-bottomed containers – like tuna or cat food cans – and use that information with charts in the publication to determine the exact number of minutes per week to irrigate in each of eleven California climate zones. The publication also explains how to avoid undesirably rapid growth from too much fertilizer. For the details, download for free Best Management Practices to Reduce Production of Organic Materials in Landscape Plantings, http://www.ciwmb.ca.gov/Publications/Organics/44301022.pdf. For more information, contact Janet Hartin at (909) 387-2166, jshartin@ucdavis.edu. Tip by Jeannette Warnert, (559) 241-7514, jwarnert@ucop.edu.
Winter cover crops clean agricultural water
The use of winter cover crops dramatically reduces the amount of nitrate and other nutrient discharge from growers’ fields, which improves the quality of water coming off agricultural land, according to UC Davis researchers. Cover crops act as filters, said Will Horwath, coordinator of the UC Davis Center for Integrated Farming Systems (CIFS) sustainable farming project. Cover crops are planted to improve soil quality and water penetration and can provide a biological source of nitrogen. “But we also know winter cover crops may affect water conservation in the summer and require changes in irrigation management,” he said. “We are using automated water samplers in the Sacramento Valley for year-round monitoring of surface runoff. Our data suggest that fields planted with cover crops may offset the water lost in the summer by increasing water infiltration in the winter.” Horwath said more research is needed to determine whether water applications can be reduced. New regulations are holding California growers accountable for detected pollutants draining off their land, which has increased interest among farmers, researchers, governmental agencies and environmental conservation groups in alternative crop-production practices that conserve soil and water resources. For more information, contact Horwath at (530) 754-6029, wrhorwath@ucdavis.edu. Tip by Lyra Halprin, (530) 752-8664, lhalprin@ucdavis.edu.
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