Soil temperature and heat flux

Authors: Sauer, Thomas; PENG, XIAOYANG - China Agricultural University

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 7/10/2018
Publication Date: 8/2/2018
Citation: Sauer, T.J., Peng, X. 2018. Soil temperature and heat flux. In: J. L. Hatfield, M. V.K. Sivakumar, J. H. Prueger, editors. Agroclimatology: Linking Agriculture to Climate, Agron. Monogr. 60th edition. Madison, WI: ASA, CSSA, and SSSA. https://doi.org/10.2134/agronmonogr60.2016.0024.
DOI: https://doi.org/10.2134/agronmonogr60.2016.0024

Interpretive Summary: The climate near the ground is influenced by the type of soil and plants growing at a location. Sunlight strikes the soil and plants and how much of that energy heats the plants, soil, and air or evaporates water is determined by characteristics of the surface. Growers manage their crops to maximize production by using as much of the sunlight as possible for crop growth. Management choices like tillage, residue management, and plant spacing can all affect the energy transfers within a crop field. In this chapter we discuss the processes and measurement techniques for soil temperature and heat flow in soil. Understanding the soil thermal regime and the effects of soil moisture and density are useful to those who want to manage their soils to be warmer or cooler. Some growers are also interested in how to protect their crops from extreme weather (drought/flood/frost/heat). Understanding temperature patterns is important because temperature affects all plant and soil processes to some degree. This type of information is useful to growers, consultants, agency personnel, and researchers who are interested in ways to manage soil temperature for crop growth and ecosystem services.

Technical Abstract: Climate near the ground is influenced by the coupling between surface conditions and large-scale meteorological forces. Crop growth and production are strongly affected by the regional climate while energy exchange within and above the crop canopy influences the local microclimate. The soil surface is the pivotal interface between surface and subsurface energy transfer processes. Soil management practices can affect the climate near the surface as soil properties affect the partitioning of incoming energy between warming the soil, evapotranspiration, and warming of the air above the ground surface. This energy partitioning and the soil thermal regime affect soil temperature, which is a key factor affecting the rate of all biological and chemical processes essential for plant growth and the provisioning of ecosystem services. The rate at which a soil conducts heat determines how fast its temperature changes during a day or with the seasons. Soil heat flux, the rate of thermal energy transfer through a unit area of soil over time, is an important parameter because it effectively couples energy transfer processes at the surface, the surface energy balance, with energy transfer processes in the soil, the soil thermal regime. Global climate change effects on temperature and precipitation patterns have important impacts on surface soil conditions that in turn have significant implications for crop growth and food security.