Search Results
Abstract
Management of the soil as a source of heat was investigated to evaluate possibilities for the conservation of oil presently used in frost protection. Two treatments involved the use of covers made from clear plastic and aluminum foil to trap solar energy. Maximum benefit was indicated for bare soil covered during the day and uncovered just before critical temperatures are reached at night. Bare soil and covered mowed grass gave an intermediate benefit while the mowed grass management scheme gave the least benefit to frost protection
Abstract
Energy used in orchard heating which moves into the soil under an orchard heater is wasted. To eliminate this loss of energy, gravel and aluminum foil were placed on the soil surface under an orchard heater. When an air gap existed between the heater base and the aluminum foil, heat flux and temperature measurements showed that the aluminum foil treatment reduced heat flux into the soil by 80-100%. The energy saved is reflected into the orchard and absorbed by the foliage in a manner similar to the radiant energy of the heater. The gravel treatment was ineffective.
Abstract
Temperatures in 4 simple thermometer shelters over a 3-1/2 hour period, under nighttime radiant cooling conditions were compared in early June, 1972. Temperatures within shelters having a single roof of wood or plastic were found to be significantly lower than air measured by an aspirated thermocouple. Temperatures in shelters having a double roof of wood did not differ significantly from air temperature. The temperature differences among single- and double-roof shelters were not considered sufficient to warrant the use of a double-roof shelter for orchard thermometer support.
Abstract
The climate of trees and vines is different from fields, meadows, and agronomic crops. These differences may be tied to the evolution of trees and vines, or they may be a peculiar result of man’s culture. Knowledge of the climate of trees and vines may be of assistance to the horticulturist in climatic modification.
Abstract
A model that computes orchard foliage temperature distributions in a heated orchard is described. The energy balance for individual foliage elements is computed, considering thermal radiation from the environment, plus the radiative and convective effects of an array of orchard heaters. The model is used to analyze various heater configurations and densities, and to determine rates of fuel consumption required for frost protection. The results indicate that radiative heating of the foliage by the heaters is as important as convective heating of the air, even though only one-fifth of the fuel contributes to radiation emission. Further, results suggest several simple passive methods for increasing the efficiency of orchard heating.