128
Heat Flow in the Soil
References
Campbell; G. S., J. D. Jungbauer, Jr., W. R. Bidlake, andR. D. Hungerford.
(1994) Predicting the effect of temperature on soil thermal conductivity.
Soil Sci. 158:307-313.
de Vries, D.A. (1963) Thermal properties of soil. In Physics of plant
environment. W.R. Van Wick (ed.). North Holland Pub. Co., Amsterdam,
pp. 21&235.
Van Wijk, W.R. (ed.), (1963) Physics of the Plant Environment, New
York: Wiley.
Problems
8.1. A common saying among farmers is "a wet soil is a cold soil." Is
this true? At what water content would you expect a mineral soil to
warm fastest (or have the largest damping depth)? What factors other
than damping depth and thermal admittance might affect the rate of
warming of a soil in the spring?
8.2. Compute the thermal conductivity of a dry sandy soil at 20" C with
a bulk density of 1.5 ~ g / m ~
(quartz content equals zero).
8.3. Rattlesnakes often seek out rocky locations for their dens where
they can retreat several meters underground in winter. If the daily
near-surface temperature of the rocks is 30" C in summer and -5" C
in winter, what is the lowest temperature the snakes would experience during the year if they choose their depth to maximize their
temperature?
8.4. Compare the conductive heat losses for a deer on frozen, saturated soil
(at 0" C) and a deer on a thick bed of leaves at the same temperature.
Assume a body temperature of 37" C, and that 30 percent of the deer's
surface is in contact with the substrate for a period of eight hours.
Would the conductive losses be about the same, less, or more if the
deer were on a frozen, dry soil?
8.5. If the temperature of your bare foot is 35" C and the temperature of
the floor is 20" C, calculate the interface temperature between your
foot and the floor for a tile floor that has a thermal admittance three
times that of your foot, and for a carpet floor that has a thermal
admittance 113 that of your foot.
Heat Flow in the Soil
References
Campbell; G. S., J. D. Jungbauer, Jr., W. R. Bidlake, andR. D. Hungerford.
(1994) Predicting the effect of temperature on soil thermal conductivity.
Soil Sci. 158:307-313.
de Vries, D.A. (1963) Thermal properties of soil. In Physics of plant
environment. W.R. Van Wick (ed.). North Holland Pub. Co., Amsterdam,
pp. 21&235.
Van Wijk, W.R. (ed.), (1963) Physics of the Plant Environment, New
York: Wiley.
Problems
8.1. A common saying among farmers is "a wet soil is a cold soil." Is
this true? At what water content would you expect a mineral soil to
warm fastest (or have the largest damping depth)? What factors other
than damping depth and thermal admittance might affect the rate of
warming of a soil in the spring?
8.2. Compute the thermal conductivity of a dry sandy soil at 20" C with
a bulk density of 1.5 ~ g / m ~
(quartz content equals zero).
8.3. Rattlesnakes often seek out rocky locations for their dens where
they can retreat several meters underground in winter. If the daily
near-surface temperature of the rocks is 30" C in summer and -5" C
in winter, what is the lowest temperature the snakes would experience during the year if they choose their depth to maximize their
temperature?
8.4. Compare the conductive heat losses for a deer on frozen, saturated soil
(at 0" C) and a deer on a thick bed of leaves at the same temperature.
Assume a body temperature of 37" C, and that 30 percent of the deer's
surface is in contact with the substrate for a period of eight hours.
Would the conductive losses be about the same, less, or more if the
deer were on a frozen, dry soil?
8.5. If the temperature of your bare foot is 35" C and the temperature of
the floor is 20" C, calculate the interface temperature between your
foot and the floor for a tile floor that has a thermal admittance three
times that of your foot, and for a carpet floor that has a thermal
admittance 113 that of your foot.