Submitted to: Encyclopedia of Soil Science
Publication Type: Book / chapter
Publication Acceptance Date: 12/18/2001
Publication Date: 7/8/2002
Citation: SAUER, T.J. SOIL HEAT FLUX. ENCYCLOPEDIA OF SOIL SCIENCE. 2002. LAL, R., EDITOR. MARCEL DEKKER, INC., NEW YORK, NY. P. 647-649. Interpretive Summary: Most of the weather we experience is a result of the amount of sunshine, presence or absence of clouds, and the strength and direction of the wind. For plants rooted in the ground though, what matters most are the conditions in the soil. The amount of heat that gets transferred from the surface down into the soil is called the soil heat flux. Soil heat flux depends on soil properties like wetness and particle size and also on whether the surface is bare or is covered by a mulch or growing plants. Soil temperature affects many processes in soil like degradation of organic matter and breakdown of pesticides. This research will be of benefit to farmers who will use it to better manage surface conditions that can make the soil warmer or cooler.
Technical Abstract: The range of climatic conditions that exist on the earth's land surface are a result of varying physical position (elevation and latitude) and the influence of large-scale meterological forces such as ocean and air currents. The soil plays an integral role in influencing the climate near the surface. Properties of the soil surface affect how much of the energy in sunlight is reflected back to the atmosphere or used to evaporate water, grow plants, warm the air above the ground, or warm the soil. The amount of thermal energy that moves through an area of soil in a length of time is referred to as the soil heat flux or heat flux density. Soil heat flux is a measure of how much energy moves into or out of the soil, which determines how warm the soil is and how fast its temperature changes in a day or between seasons. Soil temperature is one of the key factors that determines the rate of chemical and biological processes in the soil.