Anomalous Bright Loamy Anomalous Bright Loamy Soils: Newly Recognized Soils: Newly Recognized Hydric Soils in the Mid Hydric Soils in the Mid Atlantic Coastal PlainAtlantic Coastal Plain

Martin C. RabenhorstMartin C. RabenhorstUniversity of MarylandUniversity of Maryland

Dept. of Environmental Science and Dept. of Environmental Science and TechnologyTechnology

College Park, MDCollege Park, MD

From FIHSUSFrom FIHSUS Hydric Soils: “that formed under conditions of Hydric Soils: “that formed under conditions of

saturation, flooding, or ponding long enough during saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions the growing season to develop anaerobic conditions in the upper part” (Federal Register, July 13, 1994). in the upper part” (Federal Register, July 13, 1994).

Nearly all hydric soils exhibit characteristic Nearly all hydric soils exhibit characteristic morphologies that result from repeated periods of morphologies that result from repeated periods of saturation and/or inundation for more than a few saturation and/or inundation for more than a few days. This anaerobiosis promotes biogeochemical days. This anaerobiosis promotes biogeochemical processes, such as processes, such as the accumulation of organic matter and the accumulation of organic matter and the reduction, translocation, and/or accumulation of iron and the reduction, translocation, and/or accumulation of iron and

other reducible elements. other reducible elements. These processes result in characteristic morphologies These processes result in characteristic morphologies

…. making them particularly useful for identifying …. making them particularly useful for identifying hydric soils.hydric soils.

Typical “Hydric” Soil

Organic matter accumulation

Depletion of iron oxides from the matrix

Segregation of iron oxides into prominent concentrations

The ProblemThe Problem Soils identified that meet saturation and Soils identified that meet saturation and

reduction requirements for hydric soils reduction requirements for hydric soils But they do not show the typical But they do not show the typical

morphological features of hydric soilsmorphological features of hydric soils

Not dominantly grayNot dominantly gray Loamy in texture (loams Loamy in texture (loams

and silt loams)and silt loams)

Anomalous Anomalous Bright Loamy Bright Loamy Soils ABLSSoils ABLS

Anecdotal observations led to a Anecdotal observations led to a research studyresearch study

M.S. Thesis of Philip K. ZurheideM.S. Thesis of Philip K. Zurheide Under the guidance of the Mid-Under the guidance of the Mid-

Atlantic Hydric Soils CommitteeAtlantic Hydric Soils Committee

Research hypotheses for Research hypotheses for the explanation of the ABLS the explanation of the ABLS

phenomenonphenomenon Soils not saturated long enoughSoils not saturated long enough Oxyaquic conditions (saturated by not Oxyaquic conditions (saturated by not

reducing)reducing) Parent materials inherently resistant to color Parent materials inherently resistant to color

change (analogous to TF2 – red parent change (analogous to TF2 – red parent material)material)

Low lateral hydraulic gradient – sea level riseLow lateral hydraulic gradient – sea level rise*

F20. Anomalous Bright F20. Anomalous Bright Loamy Soils.Loamy Soils.

For use in MLRA 149A of LRR S and MLRAs 153C and For use in MLRA 149A of LRR S and MLRAs 153C and 153D of LRR T; for testing in MLRA 153B of LRR T. 153D of LRR T; for testing in MLRA 153B of LRR T.

Within 200 m (656 feet) of estuarine marshes or Within 200 m (656 feet) of estuarine marshes or waters and within 1 m (3.28 feet) of mean high water, waters and within 1 m (3.28 feet) of mean high water,

a mineral layer at least 10 cm (4 inches) thick starting a mineral layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface within 20 cm (8 inches) of the soil surface

with a matrix (60 percent or more of the volume) with a matrix (60 percent or more of the volume) chroma of less than 5 and 10 percent or more distinct chroma of less than 5 and 10 percent or more distinct or prominent redox concentrations occurring as soft or prominent redox concentrations occurring as soft masses or pore linings and/or depletions.masses or pore linings and/or depletions.

User Notes: These soils are expected to occur on User Notes: These soils are expected to occur on linear or convex landforms that are adjacent to linear or convex landforms that are adjacent to estuarine marshes or waters.estuarine marshes or waters.

For use in MLRA For use in MLRA 149A of LRR S 149A of LRR S and MLRAs and MLRAs 153C and 153D 153C and 153D of LRR Tof LRR T

for testing in MLRA for testing in MLRA 153B of LRR T153B of LRR T

Figure 1 Location of the study site at Eastern Neck NWR. Figure c shows topographicsurvey points and also the three transect points superimposed on the topographicsurface. Elevations are in feet.

Figure 1 Location of the study site at Eastern Neck NWR. Figure c shows topographicsurvey points and also the three transect points superimposed on the topographicsurface. Elevations are in feet.

Eastern Neck Island NWR

160 m

Within 200 m (656 Within 200 m (656 feet) of estuarine feet) of estuarine marshes or waters marshes or waters and within 1 m (3.28 and within 1 m (3.28 feet) of mean high feet) of mean high water, water,

A mineral layer at A mineral layer at least 10 cm (4 least 10 cm (4 inches) thick inches) thick starting within 20 starting within 20 cm (8 inches) of cm (8 inches) of the soil surface the soil surface

Can be overlain Can be overlain by by anyany material material

matrix (60 percent matrix (60 percent or more of the or more of the volume) chroma of volume) chroma of less than 5 (closer less than 5 (closer to 4 than to 6)to 4 than to 6)10 percent or 10 percent or more distinct or more distinct or prominent redox prominent redox concentrations concentrations occurring as soft occurring as soft masses or pore masses or pore linings and/or linings and/or depletions.depletions.

Eastern Neck Islanda layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface with a matrix chroma of less than 5 10 percent or more distinct or prominent redox concentrations and/or depletions

10YR 3/1

10YR 4/3

2.5Y 5/4 with 30% 10YR 5/6 concentrations

7.5YR 5/6 with 30% 10YR 5/8 concentrations20% 2.5 6/4 and 10% 2.5Y 6/3 depletions

A

AE

BE

Bt1

Bt2

EN lowEN lowa layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface with a matrix chroma of less than 5 10 percent or more distinct or prominent redox concentrations and/or depletions

10YR 3/110YR 3/1

10YR 4/3 1% 7.5YR 4/6 concentrations10YR 4/3 1% 7.5YR 4/6 concentrations

2.5Y 6/4 matrix2.5Y 6/4 matrix5-10% 10YR 5/8; 10% 10YR 4/6 concentrations 5-10% 10YR 5/8; 10% 10YR 4/6 concentrations 25% 2.5Y 6/325% 2.5Y 6/3 depletions

A

EA

BE

Bt1

BW highBW higha layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface with a matrix chroma of less than 5 10 percent or more distinct or prominent redox concentrations and/or depletions

10YR 3.5/2 3% 7.5YR 3/3 concentrations10YR 3.5/2 3% 7.5YR 3/3 concentrations

2.5Y 4/2.7 7% 7.5YR 3/3 concentrations2.5Y 4/2.7 7% 7.5YR 3/3 concentrations

2.5Y 5/4 matrix2.5Y 5/4 matrix7% 7.5YR 4/6; 3% 7.5YR 3/4 concentrations7% 7.5YR 4/6; 3% 7.5YR 3/4 concentrations5% 2.5Y 5/3.2;5% 2.5Y 5/3.2; 5% 2.5Y 6/2 depletions 5% 2.5Y 6/2 depletions

A

AE

Bt1

Bt2

IOW highIOW higha layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface with a matrix chroma of less than 5 10 percent or more distinct or prominent redox concentrations and/or depletions

7.5YR 3/27.5YR 3/2

10YR 4/3 10% 7.5YR 4/6; 5% 5YR 3/4 concentrations 10YR 4/3 10% 7.5YR 4/6; 5% 5YR 3/4 concentrations 3% 2.5Y 4/2 depletions3% 2.5Y 4/2 depletions

2.5Y 5/4 35% 10YR 5/6; 3% 7.5YR 4/6 concentrations2.5Y 5/4 35% 10YR 5/6; 3% 7.5YR 4/6 concentrations

A

AB

BA

Bt1

TH lowTH low

7.5YR 2.5/1 3% 5YR 3/3 pore linings

7.5YR 2/2 10% 5YR 3/3 pore linings

2.5Y 3/3 15% 7.5YR 3/4 pore linings

A1

A2

AE

EB

Bt

a layer at least 10 cm (4 inches) thick starting within 20 cm (8 inches) of the soil surface with a matrix chroma of less than 5 10 percent or more distinct or prominent redox concentrations and/or depletions

ABLSABLS

An indicator now approved to An indicator now approved to accommodate these problem soils.accommodate these problem soils.

Should be kept in mind when Should be kept in mind when examining low elevation soils on the examining low elevation soils on the coastal plain within 200 meters of coastal plain within 200 meters of tidal water or tidal marshtidal water or tidal marsh

We would like to express We would like to express appreciation to the following appreciation to the following organizations who helped to organizations who helped to

support this work:support this work: Maryland Department of the EnvironmentMaryland Department of the Environment US Environmental Protection AgencyUS Environmental Protection Agency Maryland Agricultural Experiment StationMaryland Agricultural Experiment Station Mid-Atlantic Hydric Soil CommitteeMid-Atlantic Hydric Soil Committee