Calag Archive

Growing concern over the impacts of air quality on human health and the possible links between agricultural production and air quality has sparked interest in determining which agricultural practices produce significant amounts of dust and how dust generation can be reduced. A comparison of the dust generated by a conventional almond harvester with dust generated by a harvester modified to reduce dust was made by measuring particulate matter collected on air sampling filters in an orchard in the Sacramento Valley. Results show that the modified harvester produced significantly less respirable and total dust Equipment modification holds considerable potential to reduce occupational exposure to dust and to reduce impacts of agriculture on ambient air quality.

Members of the San Joaquin River Management Program's Water Quality Subcommittee have developed a water-quality forecasting model to help improve the timing, coordination and management of agricultural drainage and reservoir releases into the San Joaquin River. The goal of this effort is to improve water quality in the San Joaquin River and to meet federal and state water-quality objectives for salt, boron and selenium. A graphical user interface has been developed and features have been added to make this computer software useful and accessible to a wide range of decision makers.

Surface irrigation may lead to thick depositional crusts at the soil surface, which can reduce infiltration rate. To break the crust on the sides of the bed near the bottom of a furrow, we developed a torpedo-shaped, winged cultivator. Field experiments were conducted on a tomato crop at UC Davis on Yolo loam soil during the summer of 1992. Breaking the crust with the device increased cumulative infiltration significantly, by almost 30%.

Trees provide shade, reduce noise and make cities more attractive, among other benefits, but their survival depends on long-term care from humans. A survey of residents in three California cities found that people who planted trees themselves were more satisfied with the outcome than residents whose trees were planted by a city employee or a developer. Residents who participated in an organized planting program were also more likely to receive information on tree maintenance. Overall, 90% of the program participants received maintenance information, compared with only 16% of the nonparticipants.

Weed competition is recognized as a factor affecting survival of California blue oak seedlings in artificial plantings. Three alternative weed-control strategies were examined in a series of annual plantings at two locations using 2- to 3-month-old nursery stock. The effects of herbicides, porous plastic mulch mats and impervious plastic mats were compared. No one strategy was superior, but all resulted in greater seedling survival than with no weed control, and generally also resulted in taller blue oaks. Use of herbicides was the least-expensive weed-control method. Much of the seedling mortality was attributed to depredation by rodents.

A survey was conducted to assess the attitudes of past and current members of the California Dairy Herd Improvement Association (CDHIA) toward the DHIA program. Members placed importance on service and production data. Northern and southern DHIA members rated their local DHIA supervisor high with regard to knowledge and service. All regions rated their local DHIA management high with regard to knowledge and service. Over 50% of the northern and southern DHIA members rated laboratory service high. All regions were satisfied with the service of the dairy records processing centers. Cost and the dairies' adoption of on-farm milk-weight meters and/or computers were the most frequently cited reasons for discontinuing DHIA membership. Based on information collected in this survey, CDHIA members continue to look to DHIA records for production and management information.

Rain cracking of sweet cherry fruit is a worldwide problem and has resulted in substantial crop losses of California cherries in each of the past 4 years (1993–1996). Various strategies to reduce cracking have provided inconsistent results. During 1996, however, rain-timed applications of calcium chloride (CaCl₂) via overtree sprinklers reduced the overall percentage of rain-cracked ‘Bing’ cherry fruit by nearly half at three locations in the Central Valley. Although these results were obtained in only one season, their consistency across sites is encouraging. In addition, a preliminary observation suggests this calcium treatment may also reduce postharvest disorders of rain-exposed fruit without affecting fruit firmness, size or weight. Some marginal leaf necrosis was noted at one site, suggesting that application rates may need to be adjusted. Overtree delivery of calcium chloride during rain provides the potential for cherry growers to reduce fruit cullage from rain. While the setup and operational costs are substantial, the increases in marketable fruit may make this system a profitable investment.