California Agriculture, May-June 1999
Volume 53, Number 3
peer-reviewed research articles
Late season hay harvest provides habitat for marshland birds
by Wade L. Epperson, John M. Eadie, Daniel B. Marcum, E. Lee Fitzhugh, Richard E. Delmas
Haying of alkaline marsh and non-native annual grasses on the Ash Creek Wildlife Area has been a standard practice to enhance bird habitat since 1986. Harvest begins each year after Aug. 15 to minimize disturbance to nests and broods of greater sandhill cranes (Grus canadensis tabida) and other marsh-nesting birds. Field studies in 1996 revealed that the abundance and diversity of birds on hayed plots was equal to or greater than the abundance and diversity of birds on nonhayed plots. Greater sandhill cranes were also more abundant and spent more time foraging and less time being vigilant on hayed plots relative to plots that had not been hayed. Harvest of wild hay after nesting and brood-rearing can therefore be an important management tool to create a mosaic of habitats required by many species of marshland birds.
Past forest management promoted root disease in Yosemite Valley
by Garey W. Slaughter, David M. Rizzo
Root disease is one of the most important vegetation-management considerations in Yosemite Valley. Large trees with root decay have fallen in the valley causing human fatalities and property damage. Many of the problems associated with root disease in Yosemite Valley can be traced back to the area's history of vegetation management. Wildfire suppression and meadow draining were implemented after the arrival of Euroamericans in the mid-19th century. These practices created conditions that encouraged the development of a dense conifer forest within the valley. Tree removals for vista clearance, campground and lodging construction, and bark beetle control projects created thousands of stumps. Many of these stumps have been infected with spores of Heter-obasidion annosum, a fungal pathogen that causes root decay in conifers. The fungus has since spread from initial infection sites into the surrounding forest, creating hundreds of enlarging tree mortality gaps. Park resource managers have established a program of hazardous-tree removal, but efforts to restore natural ecosystem processes must be continuously reconciled with public safety.
Clipping chamise reduces brush fire hazard
by Theodore E. Adams, Peter B. Sands
Wildfire is a particular concern where housing and business development encroaches on highly flammable brushlands. In these areas, it may be risky to use prescribed fire to control biomass and reduce the fuel for a fire. Chamise chaparral, the most common of the brush types, was clipped to study how biomass removal affects flammability and fire hazard. The results suggest that infrequent clipping of chamise to a height of 12 inches may adequately reduce fuel volume and encourage new growth high in moisture, which lowers the flammability of vegetation.
“New” method simplifies decision of when to replace orchards
by Oscar R. Burt, Steven C. Blank
This article presents a “new” method for making decisions on when to replace depreciable assets. The method is simpler than other standard methods because it uses only known cost data, avoiding the problems of using price forecasts. An application to cling peach orchards is given to explain and illustrate the method.
Dairies adopt TQM to improve milk quality and food safety
by John H. Kirk, William C. Sischo, Donald J. Klingborg, Marit Arana, Gerald Higginbotham, Denise Mullinax, Tom Shultz
In an effort to manage antibiotics and prevent residues in meat and milk, the principles of Total Quality Management were applied to dairy farm operations. Six California dairies participated in the National Dairy Total Quality Management Program, which included dairies in 30 states. Dairy producers, their veterinarians, the UC Cooperative Extension dairy farm advisors and Veterinary Medicine Extension veterinarians collaborated during the study. During the project, all six dairies developed written treatment plans to assure that drug withdrawal deadlines were being met. Most of the participating producers judged the management protocols, treatment protocols and treatment records to be “very useful” or “somewhat useful.” Perhaps the greatest benefit was increased communication between the dairy management and its workers for a better understanding of what was expected of each worker and who was accountable.
After 2 years, imazethapyr residues have no effect on crops in Imperial Valley
by Carl E. Bell, Brent E. Boutwell
A study was conducted in the Imperial Valley to determine the effect of soil residues on subsequent rotational crops after the herbicide imazethapyr is applied to alfalfa. Imazethapyr's label recommends a plantback interval of up to 40 months for sugarbeet and most rotational crops grown in this region. Wheat, lettuce, cotton, tomato and cantaloupe yields were not reduced by imazethapyr. Broccoli, carrot, sugarbeet and sudangrass yields were lower in imazethapyr plots when these crops were sown 11 months after treatment. But after 2 years, soil residues at the maximum-allowed application rate had no effect on any of the rotational crops we studied. Therefore, imazethapyr's plantback recommendations may be too conservative for crops grown in rotation with alfalfa in the Imperial Valley.
editorial, news, letters & science briefs
Agriculture and the ecosystem: Partners for life
by W.R. Gomes
Ranchers plan to protect water quality
by John Stumbos
New direction for Sierra Nevada forests
by Robin Meadows
Fighting fire with fire science
by Jill Goetz
For the birds: Farmers accommodate wildlife