Effectiveness of wind machines: Frost protection by ramjet or conventional wind machines in deciduous orchards depends on the strength of the inversion
AuthorsG. E. Goodall
D. E. Angus
A. S. Leonard
F. A. Brooks
Authors AffiliationsG. E. Goodall, Farm Advisor, Santa Barbara County, University of California, participated in earlier wind machine tests in this project in citrus and was on loan to the Department of Agricultural Engineering for these studies; D. E. Angus, Assistant Specialist in Agriultural Engineering, University of California, Davis, conducted the frost research program of the Division of Meteorological Physics, Commonwealth Scientific and Industrial Research Organization, Australia, and was granted leave to cooperate in these studies in California; A. S. Leonard is Specialist in Agricultural Engineering, University of California, Davis; F. A. Brooks is Agricultural Engineer, University of California, Davis.
Hilgardia 11(8):7-9. DOI:10.3733/ca.v011n08p7. August 1957.
When the atmosphere 40' to 50' above ground is 13°F or more warmer than it is a few feet above the soil surface, the temperature inversion condition—in frost protection research—is considered to be strong. When the temperature difference is less than about 5°F the inversion is considered weak. The weak inversions usually found in the deciduous orchards on the floor of the Sacramento Valley appear to limit the usefulness of wind machines for frost protection unless additional heat is supplied from orchard heaters.
Also in this issue:Agricultural marketing orders: Under enabling legislation California marketing programs now interwoven in economic structure of some of state's products
Ungrafted vineyard rootstock: Eradication of unproductive rootstock vines by treatment with chemicals tested in Sonoma and Santa Clara counties
Improved oat variety: Resistant to drought, shattering and stem rust, the new Indio shows promise
Lygus bug injury to carrot seed: Pest can cause 50% or more loss of carrot seed crop unless controlled by three properly timed 10% DDT dust applications
Worm infestation of tomatoes: Western yellow-striped armyworm on tomatoes controlled in second year of trials conducted in San Joaquin County fields
Harvester for canning fruit: Exploratory trials with cling peaches and Bartlett pears to evaluate feasibility of shaking fruit onto catching frame
Defoliation of hydrangea: Chemical defoliation of hydrangea plants obtained rapidly and without injury to flower buds by prestorage treatment
Orange tortrix on avocados: Pest becoming of increasing economic importance on certain varieties of avocado in some orchards in the coastal areas
Ontogeny and structure of the phloem of tobacco
The multinucleate condition in fibers of tobacco
Morphological development of the fruit of the olive