Soil Game - Horizons From a Hat

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Natural soil forming processes give rise to distinct soil horizons, or "soil layers". The Canadian soil classification system starts off by dividing soil horizons into two distinct categories: organic and mineral horizons. Organic horizons are characterized as containing 17% or more organic matter, while mineral horizons are characterized as containing less than 17% organic matter.

Master horizons, or "main horizons" are indicated by capital letters: A, B, C, R, W. Suffixes further describe differences within the master horizons. It is important to note that different countries have slightly varying ways of classifying soils, and no one system is more correct than another. Their utility rests in their ability to accurately represent local soil conditions in a reliable manner. Because different definitions exist for varying horizon symbols, classification systems can't be mixed.

Game Instructions

A printout of organic and mineral soil master horizons and suffixes can be downloaded and printed off from HERE, for the game.

Targeted age range for this game: highschool & up

You'll need:

  • 2 hats
  • a printout of the horizons and suffixes document, cut where the lines indicate

To play:

  • Place all the master horizon cut-outs into one hat, and all the suffix cut-outs in another

After randomly selecting a master horizon from one hat and an accompanying suffix from a different hat, the objective is to determine whether or not that master horizon-suffix combination can possibly occur from natural processes in nature. If the combination is possible, describe the processes that could lead to its development. If the combination is not possible, elaborate on why that is the case.

A printout of the two reference tables below can be found HERE

Table 1. Mineral Soil Horizons (Canadian Classification System). Adapted from
Master Horizon Suffixes Basic Description
A Mineral horizon formed at or near the soil surface
Ah Accumulation of soil organic matter (SOM)
Ae Removal of clay, SOM, iron, or aluminum
B Horizon formed by accumulation of material removed from Ae horizon or by alteration of the parent material
Bh Accumulation of SOM
Bf Accumulation of iron and/or aluminum
Bss Presence of slickensides (smooth clay coating caused by stress in high clay soils)
Bv Vertic horizon caused by turbation (mixing) of material in high clay soils
Bt Accumulation of clay
Bn Strong soil structure and sodium accumulation
Bg Mottling and gleying due to water saturation
Bm Slight colour or structural changes from the parent material
C Horizon with little evidence of pedogenic activity
Cca Accumulation of Ca and Mg carbonates
Cs Accumulation of soluble salts
Ck Presence of original Ca and Mg carbonates
Css Presence of slickensides
Cg Mottling and gleying due to water saturation
R Bedrock
W Water layer
Table 2. Organic Soil Horizons (Canadian Classification System). Adapted from
Master Horizon Suffixes Basic Description
O An organic horizon developed mainly from bog vegetation; it is more commonly called peat. These materials are usually water saturated.
Of Composed of fibrous materials of readily recognizable origin
Om Organic materials in an intermediate (or mesic) stage of decomposition; some have a recognizable form, but the remainder is highly decomposed
Oh Organic material which is highly decomposed (in a humic state); the origin of the material is unrecognizable
L,F,H Organic materials that occur from the accumulation of leaves, twigs and woody materials and which overlies a mineral soil; commonly found in well to imperfectly drained forest environments.
L Leaf litter, readily recognizable
F Partially decomposed leaf and twig material (folic material)
H Humic material; decomposed organic materials with no original structures evident


  1. Canadian Society of Soil Science. 2020. Soils of Canada. [Online] Available: [August 6, 2020].
  2. Soil horizon. 2020. Retrieved August 08, 2020, from