Hydric Soil Field Indicators

Question 1

Histosol

Answer 1

A1 - Histosol (all LRRs); Typically 16” or more of the upper 32” is organic material, starting at soil surface.

Question 2

Histic Epipedon

Answer 2

A2 - Histic Epipedon (all LRRs): Typ. Surface horizon 8” or more of organic soil material. Underlain by mineral soil with chroma of 2 or less. Aquic or artificial drainage required.

Question 3

Black Histic

Answer 3

A3 - Black Histic (all LRRs): Layer of peat, mucky peat, or muck 8” or more starting ≤ 6” from the soil surface; hue of 10YR or yellower, value of 3 or less, chroma of 1 or less, underlain by mineral soil material with chroma of 2 or less. Does not require aquic conditions or artificial drainage proof.

Question 4

Hydrogen Sulfide

Answer 4

A4 - Hydrogen Sulfide (all LRRs): Rotten Egg (I.e. very wet ecosystems)

Question 5

Stratified Layers

Answer 5

A5 - Stratified Layers (LRR TRSN + more): Seveal stratified layer, starting at a depth of ≤ 6” from the soil surface. At least one of the layers has value of 3 or less and chroma of 1 or less, or it is, muck, mucky peat, peat, or a mucky modified mineral texture. Remaining layers have chroma of 2 or less. Any sandy material that constitutes the later with value 3 or less and chroma of 1 or less, must appear close to 100% masked.

Question 6

Organic Bodies

Answer 6

A6 - Organic Bodies (LRR T + more): 2% or more organic bodies of muck or mucky modified mineral texture at ≤ 6” from soil surface. Peat and mucky peat do NOT meet the requirement for indicator.

Question 7

Mucky Mineral

Answer 7

A7 - Mucky Mineral (LRR T + more): Layer of mucky modified mineral soil material 2” or more thick, starting at depth ≤ 6” from soil surface.

Question 8

1 cm Muck

Answer 8

A9 - 1 cm Muck (LRR T + more): Layer of muck 0.5” or more thick with value of 3 or less and chroma of 1 or less starting at depth of ≤ 6” from soil surface. Sand grains should not be evident.

Question 9

2 cm Muck

Answer 9

A10 - 2 cm Muck (LRR N + more): Layer of muck 0.75” or more thick with value of 3 or less and chroma of 1 or less starting at depth of ≤ 6” from soil surface. Sand grains should not be evident.

Question 10

Depleted Below Dark Surface

Answer 10

A11 - Depleted Below Dark Surface (All LRRs except few): Layer with depleted or gleyed matrix that has 60% or more chroma of 2 or less starting at ≤ 12” from soil surface. Minimum thickness of:
- 6”, or
- 2”, if consisting of fragmental soil material
Organic, loamy, or clayey layer(s) above the depleted or gleyed matrix must have value of 2 or less and chroma of 2 or less starting at a depth of ≤ 6” from soil surface and extend to depleted or gleyed matrix. Sandy material above depleted or gleyed matrix must have value of 3 or less and chroma of 1 or less starting at a depth of ≤ 6”from soil surface and extend to depleted or gleyed matrix. Sand particles must visually appear to be 100% masked.

Question 11

Thick Dark Surface

Answer 11

A12 - Thick Dark Surface (all LRRs): Layer at least 6” thick with depleted or gleyed matrix that has 60% or more chroma of 2 or less starting below 12” of the surface. Layer(s) above depleted or gleyed matrix must have value of 2.5 or less and chrome of 1 or less to a depth of 12” and a value of 3 or less and chroma of 1 or less in any remaining layers above the depleted or gleyed matrix. In any sandy material, sand particles must visually appear to be 100% masked.

Question 12

Coast Prairie Redox

Answer 12

A16 - Coast Prairie Redox (MLRA 150A of LRR T): Layer starting at a depth ≤ 6” from soil surface at least 4” thick and have matrix chroma of 3 or less with 2 percent or more distinct or prominent redox concentrations occurring as soft masses and/or pore linings.

Question 13

Sandy Mucky Mineral

Answer 13

S1 - Sandy Mucky Mineral (LRR T + more): Layer of mucky modified sandy soil material 2” or more thick starting at ≤ 6” from soil surface

Question 14

Sandy Gleyed Matrix

Answer 14

S4 - Sandy Gleyed Matrix (all LRRs except some): Gleyed matrix that occupies 60% or more of a layer starting at a depth of ≤ 6” from soil surface.

Question 15

Sandy Redox

Answer 15

S5 - Sandy Redox (all LRRs expect some): Layer starting at depth ≤ 6” from soil surface at least 4” thick and has a matrix with 60% or more chroma of 2 or less and 2% or more distinct prominent redox concentrations occurring as soft masses and/or pore linings. Note: common feature, may need to allow soil to dry to observed.

Question 16

Stripped Matrix

Answer 16

S6 - Stripped Matrix (all LRRs except some): Layer starting at depth ≤ 6” from soil surface in which iron-manganese oxides and/or organic matter have been stripped from the matrix and primary base color of the soil material has been exposed. Stripped areas and translocated oxides and/or organic matter form faintly contrasting pattern of two or more colors with diffuse boundaries. Stripped zones are 10% or more of the volume and are rounded.

Question 17

Dark Surface

Answer 17

S7 - Dark Surface (LRRs TRSN + more): Layer 4” thick, starting at depth ≤ upper 6” from soil surface, with matrix value of 3 or less and chroma of 1 or less. Particles visually appear to be 100% masked. Matrix color of the layer directly below the dark layer must have the same colors as those described above or any color that has chroma of 2 or less.

Question 18

Polyvalue Below Surface

Answer 18

S8 - Polyvalue Below Surface (LRRs TRS + more) Layer with value of 3 or less and chroma of 1 or less starting at depth ≤ 6” from soil surface. Particles visually appear to be 100% masked. Directly below this layer, 5% or more of soil volume has value of 3 or less and chroma of 1 or less, remainder of soil volume has value of 4 or more and chroma of 1 or less to a depth of 12” or to spodic horizon (whichever is less).

Question 19

Thin Dark Surface

Answer 19

S9 - Thin Dark Surface (LRRs TRS + more): Layer 2” or more thick, starting at depth of ≤ 6” from soil surface, with value of 3 or less and chroma of 1 or less. Particles visually appear to be 100% masked. This layer is underlain by a layer(s) with value of 4 or less and chroma of 1 or less to a depth of 12” or to spodic horizon (whichever is less).

Question 20

Barrier Islands 1 cm Muck

Answer 20

S12 - Barrier Islands 1 cm Muck (MLRA 153D of LRRT + more): In swale portion of dune-and-swale complexes of barrier islands, layer of muck 0.5” or more thick with value of 3 or less and chroma of 2 or less and starting at a depth of ≤ 6” from soil surface.

Question 21

Loamy Gleyed Matrix

Answer 21

F2 - Loamy Gleyed Matrix (all LRRs except some): Gleyed matrix that occupies 60% or more of a layer starting at a depth of ≤ 12” from soil surface.

Question 22

Depleted Matrix

Answer 22

F3 - Depleted Matrix (all LRRs except some): Layer that has a depleted matrix with 60% or more value of 4 or more and chroma of 2 or less and that has a minimum thickness of either:
- 2” if the 2” starts at a depth ≤ 4” of the soil surface , or
- 6”, starting at a depth ≤ 10” from soil surface
Redox concentrations, including soft iron-manganese masses and/or pore linings are required in soils with matrix colors of 4/1, 4/2, or 5/2.

Question 23

Redox Dark Surface

Answer 23

F6 - Redox Dark Surface (all LRRs except some): Layer tat is at least 4” thick, starting at ≤ 8” from the mineral soil surface, and has:
- Matrix value of 3 or less and chroma of 1 or less and 2% or more distinct or prominent redox concentrations occurring as soft masses or pore linings, or
- Matrix value of 3 or less and chroma of 2 or less and 5% or more distinct or prominent redox concentrations occurring as soft masses or pore linings.

Question 24

Depleted Dark Surface

Answer 24

F7 - Depleted Dark Surface (all LRRs except some): Redox depletions with value of 5 or more and chroma of 2 or less in a layer that is at least 4” thick, starting at depth ≤ 8” from mineral soil surface, and has:
- Matrix value of 3 or less and chroma of 1 or less and 10% or more redox depletions, or
- Matrix value of 3 or less and chroma of 2 or less and 20% or more redox depletions.

Question 25

Redox Depressions

Answer 25

F8 - Redox Depressions (all LRRs except some): In closed depressions subject to ponding, 5% or more distinct or prominent redox concentrations occurring as soft masses or pore linings in a layer that is 2” or more thick and starts at a depth ≤ 4” from soil surface.

Question 26

Iron-Manganese Masses

Answer 26

F12 - Iron-Manganese Masses (LRRs T and N + more): On flood plains, layer 4” or more thick with 40% or more chroma of 2 or less and 2% or more distinct or prominent redox concentrations occurring as soft iron-manganese masses with diffuse boundaries. Layer starts at a depth ≤ 8” from soil surface. Iron-manganese masses have value and chroma of 3 or less. Most commonly, they are black. Thickness requirement is waived if the layer is the mineral surface layer.

Question 27

Umbric Surface

Answer 27

F13 - Umbric Surface (LRRs T + more): In depressions and other concave landforms, layer 10” or more thick, starting at depth ≤ 6” from soil surface, upper 6” has value of 3 or less and chroma of 1 or less and in which the lower 4” has the same colors as those described above or any other color that has a chrome of 2 or less.

Question 28

Piedmont Floodplain Soils

Answer 28

F19 - Piedmont Flood Plain Soils (MLRAs 148 and 149A of LRR S): On flood plains, a mineral layer at least 6” thick, starting at depth ≤ 10” from the soil surface, with a matrix 60% chroma of less than 4 and 20% or more distinct or prominent redox concentrations occurring as soft masses or pore linings.

Question 29

Anomalous Bright Loamy Soils

Answer 29

F20 - Anomalous Bright Loamy Soils (MLRA 149A of LRR S and MLRAs 153C and 153D of LRR T): Within 200 meters from estuarine marshes or water and at a depth ≤ 1 meter of mean high water, a mineral layer at least 4” thick, starting at a depth ≤ 8” from the soil surface, with a matrix 60% chroma of less than 5 and 10% or more distinct or prominent redox concentrations occurring as soft masses or pore linings and/or depletions.

Question 30

Red Parent Material

Answer 30

F21 - Red Parent Material (MLRA 127 of LRR N; MLRA 145 of LRR R; and MLRAs 147 and 148 of LRR S): Layer derived from red parent material at least 4” thick, starting at a depth ≤ 10” from the soil surface with a hue of 7.5 YR or redder. Matrix has a value and chroma greater than 2 and less than or equal to 4. Layer must contain 10% or more depletions and/or distinct or prominent concentrations occurring as soft masses or pore linings. Redox depletions should differ in color by having:
- Mimimum difference of 1 value higher and 1 chroma lower than the matrix, or
- Value of 4 or more and chroma of 2 or less