Soils Lab

  Before the lab read “The Soil Profile” and “Properties  of Soils” on pages 59-62 in your textbook. Pay special attention to  Figure 4.1 and Figure 4.2.

The soil profile is made up of layers of soil that differ in color, texture, and other properties from layers above or below them. These layers are called horizons. A soil profile may contain up to six horizons, though one or more may be missing in any given profile.

Below is a general soil profile with all of the horizons present.

Oi	The O horizon is the organic horizon. It is sub-divided in Oi the leaf litter and Oa the humus. The O horizon is absent in cultivated soils
Oa
A	The A horizon is the layer where the organic material mixes with the inorganic soil.
E	The E horizon is the area of maximum leaching. It is lighter in color than the horizons above or below it.
B	The B horizon is where leached material, especially clay, accumulates.
C	The C horizon is weathered parent material little involved in soil formation.
R	The R horizon is un-weathered parent material.

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In this lab you will:
Measure the depth of each horizion.
Determine the texture using the settling tubes for the A horizion, and the texture by feel for the A, E, and B horizions.
Determine the color of the A, E, and B horizions utilizing the Munsell Soil Color Charts.
Determine the pH of the A horizion and the horizion beneith it.
Determine the prominence of roots for each horizion.
Determine the presence of special features for each horizion.

Lab Report Form

Draw a soil profile for each site visited. In chart form include the following information:

Horizon	Depth in cm	Texture	Color	pH	Prominence of roots	Other: mottling, stoniness, pans, etc.
Oi
Oa
A
E
B

Links:
Alabama State Soil