Hydric Soil Indicators

Histols (A1)

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Histic Epipedon (A2)

A histic epipedon underlain by mineral soil material with a chroma of 2 or less. Aquic conditions are required. associated with slope wetlands, not found at boundaries

Black Histic (A3)

A layer of peat, mucky peat, or muck 8 in. or more thick that starts within 6 in. of the soil surface; has a hue of 10YR or yellower, value of 3 or less, and chroma of 1 or less; and is underlain by mineral soil material with a chroma of 2 or less. saturated nearly all of the growing season, not typically found at boundaries

Reduced Vertic (F18

In Vertisols and Vertic intergrades, a positive reaction to aad that is the dominant (60% or more) conditions of a layer at least 4 in. thick within the upper 12 in. occurs for at least 7 continuous days and 28 cumulative days occurs during a normal (16 to 84% probable precipitation) or dier season and month.

Iron-Manganese Masses (F12)

On floodplains, a layer 4 in. or more thick with 40 percent or more chroma of 2 or less and 2 percent or more distinct or prominent redox concentrations occuring as soft iron-mg masses with diffuse boundaries. Occurs entirely within 12 in. of the soil surface. iron-mg masses havea value and chroma of 3 or less. Mostly they are black. thickness waived if the layer is the mineral surface layer

Loamy Gleyed Matrix (F2)

a gleyed matrix that occupies 60 percent or more of a layer starting within 12 in. of the soil surface value of 4 or more. starting withing 12 in. of the surface

Sandy Gleyed Matrix (S4)

a gleyed matrix that occupies 60 percent or more of a layer starting within 6 in. of the soil surface generally not found at boundaries

Hydrogen Sulfide (A4)

a hydrogen sulfide (rotten egg) odor within 12 in. of the soil surface common in permanently saturated parts of the region. generally not found at the boundary

Thin Dark Surface (S9)

a layer 2 in. or more thick starting within the upper 6 in. of the soil, with a value of 3 or less and a chroma of 1 or less. This layer is underlain by a layer with a value of 4 or less and chroma of 1 or less to a depth of 12 in. or to the spodic horizon, whichever is less.

Depleted Ochric (F11)

a layer 4 in. or more thick in which 60 percent or more of the matrix has a value of 4 or more and chroma of 1 or less. The layer is entirely within the upper 10 in. of the soil. only in MLRA 151

Delta Ochric (F17)

a layer 4 in. or more thick in which 60 percent or more of the matrix has a value of 4 or more and chroma of 2 or less and there are no redox concentrations. this layer occurs entirely within the upper 12 in. of the soil

Dark Surface (S7)

a layer 4 in. thick starting within 6 in. of the soil surface with a matrix value of 3 or less and chroma of 1 or less. The matrix color of the layer immediately below the dark layer must have the same colors as those described above or any color that has a chroma of 2 or less

Thick Dark Surface (A12)

a layer at least 6 in. thick with a depleted or gleyed matrix that has 60 percent or more chroma of 2 or less starting below 12 in. of the surface. The layer above the depleted or gleyed matrix must have a value of 2.5 or less and chroma of 1 or less to a depth of at least 12 in. and a value of 3 or less and a chroma of 1 or less in any remaining layers above the depleted or gleyed matrix.

Marl (F10)

a layer of marl with a value of 5 or more starting within 4 in. of the soil surface. no thickness requirements for this indicator. marl usually occurs directly over limestone

1 cm Muck (A9)

a layer of muck .5 in. or more thick with a value of 3 or less and a chroma of 1 or less starting within 6 in. of the soil surface.

Muck Presence (A8)

a layer of muck with a value of 3 or less and chroma of 1 or less starting within 6 in. of the soil surface

Loamy Mucky Mineral (F1)

a layer of mucky modified loamy or clayey soil material 4 in. or more thick starting within 6 in. of the soil surface

5 cm Mucky Mineral (A7)

a layer of mucky modified mineral soil material 2 in. or more thick starting within 6 in. of the soil surface

Sandy Mucky Minderal (S1)

a layer of mucky modified sandy soil material 2 in. or more thick starting within 6 in. of the soil surface

Stripped Matrix (S6)

a layer starting within 6 in. of the soil surface in which iron/manganese oxides and/or organic matter have been stripped from the matrix and the primary base color of the soil material has been exposed. The stripped areas and translocated oxides and/or organic matter form a faintly contrasting pattern of two or more colors with diffuse boundaries. the stripped zones are 10 percent or more of the volume and are rounded. common indicator used to determine boundaries

Coast Prairie Redox (A16)

a layer starting within 6 in. of the soil surface that is at least 4 in. thick and has a matrix chroma of 3 or less with 2 percent or more distinct or prominent redox concentrations occuring as soft masses and or pore linings.

Sandy Redox (S5)

a layer starting within 6 in. of the soil surface that is at least 4 in. thick and has a matrix with 60 percent or more chroma of 2 or less with 2 percent or more distinct or prominent redox concentrations occuring as soft masses and or pore linings. very common indicator often used in boundary of sandy soils

Redox Dark Surface (F6)

a layer that is at least 4 in. thick, is entirely within the upper 12 in. of the mineral soil, and has a matrix value of 3 or less and chroma of 1 and 2 percent or more distinct or prominent redox concentrations occuring as soft masses or pore linings matrix value of 3 or less and chroma of 2 or less and 5 percent or more distinct or prominent redox concentrations occuring as soft masses or pore linings.

Depleted Matrix (F3)

a layer with a depleted matrix that has 60 percent or more chroma of 2 or less and that has a minimum thickness of either 2in. if the 2 in. is entirely within the upper 6 in. of the soil or 6 in. starting within 10 in. of the soil surface most commonly observed hydric soil indicator at wetland boundaries redox concentrations are required with matrix values/chromas of 4/1 4/2 and 5/2 with or without redox concentrations fro 5/1 and 6, 7, 8 /1 and /2

Depleted Below Dark Surface (A11)

a layer with a depleted or gleyed matrix that has 60 percent or more chroma of 2 or less, starting within 12 in. of the soil surface, and having a minimum thickness of either; 6 in. or 2 in. if the 2 in. consists of fragmental soil material loamy/glayey layer above the depleted or gleyed matrix must have a value of 3 or less and chroma of 2 or less. any sandy material above the depleted or gleyed matrix must have a value of 3 or less and a chroma of 1 or less.

Polyvalue Below Surface (S8)

a layer with a value of 3 or less and chroma of 1 or less starting within 6 in. of the soil surface. Immediately below this layer, 5 percent or more of the soil volume has a value of 3 or less and chroma of 1 or less and the remainder of the soil volume has a value of 4 or more and chroma of 1 or less to a depth of 12 in. or to the spodic horizon, whichever is less

Redox Depressions (F8)

in closed depressions subject to ponding, 5 percent or more distinct or prominent redox concentrations occuring as soft masses or pore linings in a layer that is 2 in. or more thick and is entirely within the upper 6 in. of the soil. no color requirement for the soil matrix.

Umbric Surface (F13)

in depressions and other concave landforms, a layer 10 in. or more thick starting within 6 in. of the soil surface in which the upper 6 in. has a value of 3 or less and chroma of 1 or less and in which the lower 4 in. has the same colors as those described above or any other color that has a chroma of 2 or less.

Piedmont Floodplain Soils (F19)

on active floodplains, a mineral layer at least 6 in. thick starting within 10 in. of the soil surface with a matrix (60% or more of the volume) chroma of less than 4 and 20 percent or more distinct or prominent redox concentrations occuring as soft masses or pore linings.

Organic Bodies (A6)

presence of 2 percent or more organic bodies of muck or a mucky modified mineral texture, approximately .5 to 1 in in diameter, starting within 6 in. of the soil surface. hard to tell in the field the amount of organic carbon which is a limiting factor

Depleted Dark Surface (F7)

redox depletions with a value of 5 or more and chroma of 2 or less in a layer that is at least 4 in. thick, is entirely within the upper 12 in. of the sineral soil, and has a matrix value of 3 or less and chroma of 1 or less and 10 percent or more redox depletions or matrix value of 3 or less and chroma of 2 or less and 20 percent or more redox depletions

Stratified Layers (A5)

several stratified layers starting within 6in. of the soil surface. At least one of the layers has a value of 3 or less with a chroma of 1 or less or is muck, mucky peat, peat, or mucky modified mineral texture. The remaining layers have chromas of 2 or less. generally in floodplains where wet soils are subject to rapid and repeated burial with thin deposits of sediment.

Anomalous Bright Loamy Soils (F20)

within 650 feet of esuarine marshes or waters and within 3.3ft of mean high water, a mineral layer at least 4 in. thick starting within 8 in. of the soil surface, with a matrix chroma of less than 5 and 10 percent or more distinct redox concentrations