Humo-Ferric Podzol (HFP)

These soils have a brownish-colored podzolic B horizon with less organic matter than the B horizon of Ferro-Humic Podzols. They occur widely both in less humid sites of the region of Podzolic soils and in humid sites. Typically they occur under coniferous, mixed, and deciduous forest vegetation but may occur under shrub and grass vegetation. Under virgin conditions these soils usually have L, F, and H horizons and may have an Ah horizon. Usually they have a light-colored Ae horizon with an abrupt lower boundary to a podzolic B horizon in which the reddest hues or highest chromas and lowest color values usually occur near the top of the horizon and fade with depth. Typically the Bf horizon of Humo-Ferric Podzols has higher color values and chromas than the Bhf horizon of Ferro-Humic Podzols. Parts of the podzolic B horizon may be cemented and the underlying material may be cemented (duric), compact and brittle (fragipan), or friable.

Humo-Ferric Podzols have a podzolic B horizon at least 10 cm thick but do not have Bh or Bhf horizons at least 10 cm thick. The podzolic B horizon of Humo-Ferric Podzols may include a thin Bhf subhorizon, but usually it is a Bf horizon only. A Bf horizon contains 0.5-5% organic C and 0.6% or more pyrophosphate-extractable Fe+Al (0.4% for sands). Pyrophosphate-extractable Fe is at least 0.3%, or the ratio of organic C to pyrophosphate-extractable Fe is less than 20, or both are true. The ratio of pyrophosphate-extractable Fe+Al to clay is more than 0.05.

Humo-Ferric Podzols are generally strongly acid and less than 50% base saturated (neutral salt). The pH-dependent CEC of the Bf horizon is usually at least 8 cmol kg-1.

Typically the podzolic B horizon of a Humo-Ferric Podzol contains less amorphous material than is characteristic of a Ferro-Humic Podzol.

Humo-Ferric Podzols are divided into ten subgroups based on the kind and sequence of the horizons, the same as Ferro-Humic Podzols.

Orthic Humo-Ferric Podzol (O.HFP)

Common horizon sequence: LFH, Ae, Bf, BC, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They are identified by the following properties:

  1. They have a podzolic B horizon at least 10 cm thick (Bf or thin Bhf and Bf).
  2. They do not have a Bh horizon at least 10 cm thick, a Bhf horizon at least 10 cm thick, an ortstein horizon at least 3 cm thick, a placic horizon, a duric horizon, a fragipan, a Bt horizon, an Ah horizon at least 10 cm thick, nor evidence of gleying in the form of distinct or prominent mottles within 1 m of the surface.

Usually Orthic Humo-Ferric Podzols have L, F, and H or O horizons and an Ae horizon. Parts of the Bf may be cemented, but it does not meet the requirements of an ortstein horizon.

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Ortstein Humo-Ferric Podzol (OT.HFP)

Common horizon sequence: LFH, Ae, Bfc, Bfj, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having an ortstein horizon at least 3 cm thick. An ortstein horizon in this subgroup is a Bhf or Bf horizon that is strongly cemented and occurs in at least one-third of the lateral extent of the pedon. Ortstein horizons are generally reddish brown to very dark reddish brown in color. Usually Ortstein Humo-Ferric Podzols have L, F, and H or O horizons and an Ae horizon. They may have faint mottling, and placic, duric, Ah, or Bt horizons, or a fragipan.

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Placic Humo-Ferric Podzol (P.HFP)

Common horizon sequence: LFH or O, Ae, Bf, Bfc, BC, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having a placic horizon within the control section. A placic horizon (Bhfc, Bfc, Bfgc) consists of a single thin layer (commonly 5 mm or less in thickness) or a series of thin layers that are irregular or involute, hard, impervious, commonly vitreous, and dark reddish brown to black. These thin horizons are apparently cemented by Fe-organic complexes, hydrated Fe oxides, or a mixture of Fe and Mn oxides. The placic horizon or thin iron pan may occur in any part of the B horizon and commonly extends into the BC horizon.

Placic Humo-Ferric Podzols usually have L, F, and H or O horizons and an Ae horizon. They do not have an ortstein horizon but may have a duric horizon or a fragipan. Evidence of gleying in the form of dull colors or mottling is commonly apparent especially above depressions in the placic horizon. These soils occur most commonly in wet sites in maritime regions; frequently the surface is peaty.

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Duric Humo-Ferric Podzol (DU.HFP)

Common horizon sequence: LFH, Ae, Bf, BCc, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having a duric horizon within the control section. A duric horizon is a strongly cemented horizon that does not satisfy the criteria of a podzolic B horizon. Usually it has an abrupt upper boundary to an overlying podzolic B horizon and a diffuse lower boundary at least 50 cm below. Cementation is usually strongest near the upper boundary, which occurs commonly at a depth of 40-80 cm from the mineral surface. The color of a duric horizon usually differs little from that of the parent material and the structure is usually massive or very coarse platy. Moist clods at least 3 cm thick usually cannot be broken in the hands. Air-dry clods of the material do not slake when immersed in water. Some duric horizons may meet the requirements of a Bt horizon (Btc).

Duric Humo-Ferric Podzols usually have L, F, and H horizons. They have neither an ortstein nor a placic horizon but may have an Ah horizon and mottles that indicate gleying in some part of the control section. These soils occur most commonly in coastal southwestern British Columbia.

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Fragic Humo-Ferric Podzol (FR.HFP)

Common horizon sequence: LFH, Ae, Bf, BCx, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having a fragipan within the control section. A fragipan (Bx or BCx) is a subsurface horizon of high bulk density that is firm and brittle when moist and hard to extremely hard when dry. Usually it is of medium texture. Commonly it has bleached fracture planes separating very coarse prismatic units. The secondary structure is platy. Usually the fragipan has a color similar to that of the parent material but differs in structure and consistence and sometimes in bulk density. The upper boundary of a fragipan is usually either abrupt or clear, but the lower boundary is usually diffuse. Commonly it is necessary to dig to about 3 m to expose clearly the material beneath the lower boundary of the fragipan. Air-dry clods of fragipans slake in water. A fragipan may have clay skins and meet the limits of a Bt horizon (Btx).

Fragic Humo-Ferric Podzols usually have L, F, and H horizons and an Ae horizon. They have neither ortstein, placic, nor duric horizons but may have an Ah horizon and mottles that indicate gleying at some depth within the control section.

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Luvisolic Humo-Ferric Podzol (LU.HFP)

Common horizon sequence: LFH, Ae, Bf, Bt, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having a Bt horizon of which the upper boundary is at a depth of more than 50 cm from the mineral surface. If the upper boundary of the Bt horizon is ≤50 cm from the surface, the soil is classified in the Luvisolic order.

Luvisolic Humo-Ferric Podzols usually have L, F, and H horizons and an Ae horizon. They may also have an Ah horizon. They have neither ortstein, duric, nor placic horizons, nor a fragipan but may have mottles that indicate gleying at some depth within the control section.

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Sombric Humo-Ferric Podzol (SM.HFP)

Common horizon sequence: LFH, Ah, Ae, Bf, BC, C

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having an Ah horizon at least 10 cm thick.

Usually Sombric Humo-Ferric Podzols have L, F, and H horizons and may have an Ae horizon. They have neither ortstein, placic, duric, nor Bt horizons, nor a fragipan, nor distinct or prominent mottles that indicate gleying.

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Gleyed Humo-Ferric Podzol (GL.HFP)

Common horizon sequence: LFH or O, Aegj, Bfgj, BCg, Cg

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Orthic Humo-Ferric Podzols by having distinct or prominent mottles that indicate gleying, within 1 m of the surface. They usually have thick L, F, and H or O horizons and have neither ortstein, placic, duric, nor Bt horizons, a fragipan, nor an Ah horizon at least 10 cm thick.

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Gleyed Ortstein Humo-Ferric Podzol (GLOT.HFP)

Common horizon sequence: LFH or O, Aegj, Bfcgj, Bfjcjgj, Cg

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Ortstein Humo-Ferric Podzols by having distinct or prominent mottles that indicate gleying, within 1 m of the surface. They usually have thick L, F, and H or O horizons and may have Ah, Ae, Bt, placic, or duric horizons, or a fragipan.

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Gleyed Sombric Humo-Ferric Podzol (GLSM.HFP)

Common horizon sequence: LFH or O, Ah, Aegj, Bfgj, BCg, Cg

These soils have the general properties specified for the Podzolic order and the Humo-Ferric Podzol great group. They differ from Sombric Humo-Ferric Podzols by having distinct or prominent mottles that indicate gleying, within 1 m of the surface. They usually have thick L, F, and H or O horizons and may have an Ae horizon. They have neither ortstein, placic, duric, nor Bt horizons, nor a fragipan.

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Note: Diagnostic horizons are underlined.