Calculate soil temperature by depth, daily or seasonal variation, and damping depth or time lag from thermal diffusivity and surface temperatures.

Idealized estimates. Periodic modes assume uniform, constant diffusivity and sinusoidal surface temperature; they omit freezing, water movement and layering. The exponential profile requires a calibrated decay coefficient.

Enter a measured or justified value for the soil and moisture conditions.

Use the same local clock as the surface maximum.

Related Calculators

Soil Temperature Formula

The following equation is used to calculate the soil temperature.

Tโ‚›oil = Td + (Tโ‚›urface - Td) ร— exp(- k ร— Depth)
  • Where T_soil is the soil temperature (ยฐC)
  • T_surface is the surface temperature (ยฐC)
  • Depth is the depth in meters (m)

Choose the quantity to solve and enter the other required values. Depth is in meters in the profile formula; Td and k must be supplied for the site.

What is a Soil Temperature Calculator?

Definition:

A Soil Temperature Calculator estimates daily or seasonal temperatures using an idealized periodic conduction model, or evaluates a separately calibrated exponential depth profile. The latter uses a user-supplied deep reference temperature Td and decay coefficient k; 10ยฐC and k = 1/m are example values only.

How to Calculate Soil Temperature?

Example Problem:

The following example outlines the steps and information needed to calculate the soil temperature parameter.

First, determine the surface temperature. In this example, the surface temperature is 25ยฐC.

Next, determine the depth. In this example, the depth is 2 meters, Td = 10ยฐC and k = 1/m.

Finally, calculate the soil temperature using the formula above:

T_soil = Td + (T_surface - Td)*exp(-k*Depth)

T_soil = 10 + (25 - 10)*exp(-2)

T_soil โ‰ˆ 12.03 ยฐC

FAQ

What factors can affect soil temperature readings?

Soil temperature can be influenced by factors such as soil composition, moisture levels, vegetation cover, and the time of day. These factors affect temperature changes, attenuation and phase lag with depth.

Why is a constant deep soil temperature of 10ยฐC used in the calculation?

10ยฐC is used only in the worked example. Enter a deep reference appropriate to the site; it is not a universal soil temperature.

Can this calculator be applied to all soil types?

While the calculator uses a simplified exponential decay model for estimation, actual soil temperatures may vary depending on soil type, structure, and moisture. For more precise results, a more detailed analysis might be necessary.