The decomposition level of folic material is based on how readily discernible the original plant structures are. The four major folic horizon designations are L, F, and H, for a more detailed description see the CSSC.

L This organic horizon is characterized by an accumulation of organic matter in which the original structures are easily discernible.

F This organic horizon is characterized by an accumulation of partly decomposed organic matter. Some of the original structures are difficult to recognize. The material may be partly comminuted by soil fauna as in moder, or it may be a partly decomposed mat permeated by fungal hyphae as in mor.

H This organic horizon is characterized by an accumulation of decomposed organic matter in which the original structures are indiscernible. This horizon differs from the F by having greater humification due chiefly to the action of organisms. It is frequently intermixed with mineral grains, especially near the junction with a mineral horizon.

Hi Some differentiate an Incorporated Humus when organic granulates are intensely mixed with mineral particles at the boundary between H and Ah.

This organic horizon is developed mainly from mosses, rushes, and woody materials (wetlands). It is divided into the subhorizons Of, Om and Oh, for a detailed description see the CSSC. In the following the acronym vPS is used for von Post Scale.

Of This O horizon consists largely of fibric materials that are readily identifiable as to botanical origin. (Of) has 40% or more of rubbed fiber by volume, rubbed fiber is the fiber that remains after rubbing a sample of the layer about 10 times between the thumb and forefinger. (vPS 1-4)

• Fennic horizons are derived from rushes, reeds, and sedges.
• Silvic horizons are derived from wood, moss and other herbaceous plants.
• Sphagnic horizons are derived from sphagnum mosses.

Om This O horizon consists of mesic material, which is at a stage of decomposition intermediate between fibric and humic materials. It has a rubbed fiber content ranging from 10% to less than 40%. (vPS 5-6)

Oh This O horizon consists of humic material, which is at an advanced stage of decomposition. The horizon has the lowest amount of fiber, the highest bulk density, and the lowest saturated water-holding capacity of the O horizons. The rubbed fiber content is less than 10% by volume. (vPS 7-10)

Oco Coprogenous earth is composed of aquatic plant debris modified by aquatic animals.

Brief description for the most commonly used suffixes, for a complete list with a more detailed description see the Canadian System for Soil Classification

e Characterized by the eluviation of clay, Fe, Al, or organic matter, alone or in combination. 
(Ae or Ahe) 
Light colored near surface horizon.

f Enriched with amorphous material, principally Al & Fe, combined with organic matter. 
(Bf, Bhf, Bfg, Bhfg, Bgf) 
Reddish brown subsurface horizon with significant accumulation of iron, aluminum and/or clay.

g Characterized by gray colors, or prominent mottling or both, indicating permanent or periodic intense reduction. 
(Aeg, Bg, Bfg, Bhfg, Btg, Bgca, Bgf, Cg, Ckg, Ccag, Csg, Csag)

h Characterized by an enrichment with organic matter.
 (Ah, Ahe, Bh, Bhf). 
Dark colored, mineral surface horizons.

j Enriched Modifier of suffixes e, f, g, n, t, and v used to denote an expression of, failure to meet, the specified limits of the suffix it modifies. 
(Aej, Btj, Btgj, Bmgj, Bntk,, Bnk, Ck, Ofk, Omk)

m Slightly altered by chemical weathering (hydrolysis, oxidation, or solution, or all three) to give a change in color or structure, or both. 
(Bm, Bmk, Bms, not Bmj) 
Brownish subsurface horizon with only slight addition of iron, aluminum or clay.

p Disturbed by human activities such as cultivation, plough layer 
(Ap, Ofp)

t Enriched Illuvial horizon enriched with silicate clay. 
(Bt, Btj, Btg) 
A Bt horizon which has developed in materials which are a significantly different in texture (mode of deposition) from the horizons a above.

other Other suffixes: b, c, ca, cc, n, k, s, sa, ss, u, v, x, y, z