LOCATION POTOBAC MDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, active, nonacid, mesic Fluvaquentic Endoaquepts
TYPICAL PEDON: Potobac loam on a wooded floodplain. (Colors are for moist soil unless otherwise indicated.)
A1--0 to 10 cm (0 to 4 inches); dark brown (10YR 3/3) loam; weak coarse subangular blocky structure parting to moderate fine subangular blocky; nonsticky, slightly plastic; few fine prominent yellowish red (5YR 4/6) soft masses of iron accumulation along root channels; strongly acid; clear wavy boundary.
A2--10 to 20 cm (4 to 8 inches); 60 percent grayish brown (2.5Y 5/2) and 40 percent dark yellowish brown (10YR 3/4) loam; weak, coarse and medium subangular blocky structure; less than 1 percent subrounded mixed gravel; strongly acid; clear wavy boundary. (Combined thickness of the A horizons is 3 to 25 cm)
Bg1--20 to 33 cm (8 to 13 inches); olive gray (5Y 5/2) loam; weak coarse subangular blocky structure; nonsticky, slightly plastic; many medium prominent red (2.5YR 5/8) soft masses of iron accumulation; less than 1 percent subrounded mixed gravel; strongly acid; gradual wavy boundary.
Bg2--33 to 43 cm (13 to 17 inches); olive gray (5Y 5/2) loam; weak coarse subangular blocky structure; nonsticky, slightly plastic; common coarse prominent reddish brown (5YR 4/4) soft masses of iron accumulation; neutral; abrupt wavy boundary. (Combined thickness of the Bg horizon is 15 to 81 cm)
Cg1--43 to 102 cm (17 to 40 inches); dark grayish brown (2.5Y 4/2) sandy loam; massive; nonsticky, slightly plastic; 5 percent, by volume, subrounded mixed gravel; neutral; gradual wavy boundary.
Cg2--102 to 152 cm (40 to 60 inches); grayish brown (2.5Y 5/2) very gravelly sand; single grain; nonsticky, nonplastic; 45 percent, by volume, subrounded mixed gravel; neutral.
TYPE LOCATION: Charles County, Maryland; about 1.75 miles east on Poplar Hill Road from its intersection with Leonardtown Road in Waldorf, Maryland; 1.4 miles south on Gardiner Road to edge of field; approximately 2000 feet south along edge of woods to southernmost corner of field; 100 feet south into woods along boardwalk; 3 feet east of boardwalk. USGS Hughesville topographic quadrangle; latitude 38 degrees 35 minutes 30.3 seconds N and longitude 76 degrees 50 minutes 39.2 seconds W, NAD 83.
RANGE IN CHARACTERISTICS:
Depth to Bedrock: Greater than 183 cm (72 inches)
Depth to Seasonal High Water Table: 0 to 25 cm (0 to 10 inches), September to June
Rock Fragment content: 0 to 10 percent, by volume in the A horizon, 0 to 20 percent, by volume, in the Bg horizon, and 0 to 90 percent, by volume, in the Cg horizon
Soil Reaction: Strongly acid to slightly alkaline, except where limed. Most pedons have slightly acid to neutral pH values at depths greater than 76 cm (30 inches).
RANGE OF INDIVIDUAL HORIZONS:
A or Ap horizon:
Color--hue of 7.5YR to 2.5Y, value of 3 to 5 and chroma of 1 to 4, or is neutral
with value of 3 to 5
Texture (fine-earth fraction)--loam, silt loam, or fine sandy loam
Redoximorphic features (if they occur)--iron masses in shades of red, yellow or brown, and iron depletions in shades of brown, yellow, olive or gray
Bg horizon:
Color--hue of 7.5YR to 5Y, value of 4 to 7 and chroma of 1 or 2, or is neutral with value of 5 to 7
Texture (fine-earth fraction)--loam, silt loam or fine sandy loam
Redoximorphic features (if they occur)--iron masses in shade of red, yellow or brown
BCg horizon (if it occurs):
Color--hue of 7.5YR to 5Y, value of 4 to 7 and chroma of 1 or 2, or is neutral with value of 5 or 6.
Texture (fine-earth fraction)--loamy sand, sandy loam, fine sandy loam or loam
Redoximorphic features (if they occur)--iron masses in shades of red, yellow or brown
Cg horizon:
Color--hue of 10YR to 5Y, value of 4 to 7 and chroma of 1 or 2, or is neutral with value of 4 to 7
Texture (fine-earth fraction)--coarse sand, sand, loamy coarse sand, loamy sand, sandy loam or fine sandy loam.
Redoximorphic features (if they occur)--iron masses in shade of red, yellow or brown
Ab horizon (if it occurs):
Color--hue of 10YR, value of 3 or 4 and chroma of 1.
Texture (fine-earth fraction)--loamy fine sand, clay loam or silty clay loam.
Redoximorphic features (if they occur)--iron masses in shade of red, yellow or brown and iron depletions in shades of brown, yellow, olive or gray
COMPETING SERIES:
Holderton soils in the same family--have formed in recent alluvium from glacial drift
Hatboro soils in a closely related family--are fine-loamy in the particle size control section
GEOGRAPHIC SETTING:
Landscape: Coastal plain
Landform: Floodplain
Parent Material: Sandy and loamy fluvial sediments
Slope: 0 to 2 percent
Elevation: 1 to 61 meters (2 to 200 feet)
Frost-free period: 180 to 210 days
Mean Annual Air Temperature: 11 to 14 degrees C. (52 to 57 degrees)
Mean Annual Precipitation: 1016 to 1270 cm (40 to 50 inches)
GEOGRAPHICALLY ASSOCIATED SOILS:
Issue soils--somewhat poorly drained on similar landforms
Mannington soils--very poorly drained soils on low floodplains near sea level
Transquaking soils--very poorly drained soils of tidal marshes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage Class (Agricultural): Poorly drained
Internal Free Water Occurrence Class: Very shallow and persistent
Flooding Frequency and Duration Classes: Frequent for brief periods
Ponding Frequency and Duration Classes: None
Index Surface Runoff Class: High or very high
Saturated Hydraulic Conductivity Class: Moderately high to high
Permeability Class (obsolete): Moderate
Shrink-swell Potential Class: Low
USE AND VEGETATION:
Major Uses: Pasture, woodland and wildlife habitat
Dominant Vegetation: Where cultivated: grass-legume hay mixture. Where wooded: Sweetgum (Liquidambar styraciflua), ash (Fraxinus spp.), sycamore (Platanus occidentalis), red maple (Acer rubrum), loblolly pine and shortleaf pine, spicebush (Lindera benzoin), greenbrier (Smilax spp.)
DISTRIBUTION AND EXTENT:
Distribution: Floodplains of the mid-Atlantic Coastal Plain of Maryland; MLRA 149A.
Extent: Small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Charles County, Maryland, 2007.
REMARKS: Potobac soils were previously mapped as Bibb, Iuka, Mixed Alluvial areas and Swamp.
Diagnostic horizons and soil characteristics recognized in this pedon are:
Ochric epipedon--the zone from 0 to 20 cm (A horizon)
Aquic conditions--the soil is seasonally saturated with water within 25 cm of the surface
Cambic horizon--the zone from 20 to 43 cm (Bg horizons)
Series control section--the zone from 0 to 150 cm
ADDITIONAL DATA: Reference particle size data is available for pedons S01MD-017-003 and S01MD-017-004 from the University of Maryland Pedology laboratory.