LOCATION CROOM                   MD

Established Series
SYD-DAS/Rev. MDJ
11/2015

CROOM SERIES

MLRA(s):149A
Depth Class: Very Deep
Drainage Class (Agricultural): Well Drained
Saturated Hydraulic Conductivity Class: Moderately high
Permeability Class (obsolete): Moderately Slow to Slow
Landscape: Northern Atlantic Coastal Plain
Parent Material: Gravelly Fluvial Deposits
Slope: 0 to 60 percent
Mean Annual Air Temperature (type location): 54.5 degrees F.
Mean Annual Precipitation (type location): 44 inches

TAXONOMIC CLASS: Loamy-skeletal, siliceous, semiactive, mesic Typic Hapludults

TYPICAL PEDON: Croom silt loam on a 12 percent slope in a cultivated field. (Colors are for moist soil unless otherwise indicated.)

Ap1--0 to 3 centimeters (0.0 to 1.2 inches); very dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2), dry; moderate medium granular structure; very friable, moderately sticky, nonplastic; common very fine and fine roots throughout; extremely acid, pH 4.0; clear smooth boundary.

Ap2--3 to 23 centimeters (1.2 to 9.1 inches); dark yellowish brown (10YR 4/4) loam; moderate coarse subangular blocky structure; very friable, moderately sticky, nonplastic; few very fine and fine roots throughout; few fine tubular pores; 6 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0; abrupt smooth boundary.

Bt1--23 to 33 centimeters (9.1 to 13.0 inches); strong brown (7.5YR 4/6) very gravelly clay loam; strong coarse subangular blocky structure; friable, moderately sticky, nonplastic; few medium roots throughout; few fine tubular pores; 15 percent continuous prominent dark yellowish brown (10YR 4/4), moist, clay films on all faces of peds; 40 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0; clear wavy boundary.

Bt2--33 to 76 centimeters (13.0 to 29.9 inches); strong brown (7.5YR 4/6) extremely gravelly sandy clay loam; weak fine subangular blocky structure; friable, moderately sticky, nonplastic; few medium roots throughout; few medium tubular pores; 15 percent continuous prominent dark yellowish brown (10YR4/4), moist, clay films on all faces of peds; 65 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0; gradual smooth boundary.

Bt3--76 to 137 centimeters (29.9 to 53.9 inches); dark yellowish brown (10YR 4/6) extremely gravelly sandy clay loam; weak very fine subangular blocky structure; friable, moderately sticky, nonplastic; few fine roots throughout; 15 percent continuous prominent dark yellowish brown (10YR 4/4), moist, clay films on all faces of peds; 70 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0; gradual smooth boundary.

BCt--137 to 168 centimeters (53.9 to 66.1 inches); strong brown (7.5YR 4/6) extremely gravelly sandy clay loam; massive; friable, slightly sticky, nonplastic; few fine roots throughout; 5 percent continuous prominent dark yellowish brown (10YR 4/4), moist, clay films on surfaces along root channels; 10 percent coarse prominent pinkish gray (5YR 6/2), moist, iron depletions throughout; 10 percent 75- to 250-millimeter unspecified fragments and 60 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0; gradual smooth boundary.

BC--168 to 203 centimeters (66.1 to 79.9 inches); dark yellowish brown (10YR 4/6) extremely gravelly coarse sandy loam; massive; friable, slightly sticky, nonplastic; few very fine and fine roots throughout; few very fine interstitial pores; 5 percent continuous prominent dark yellowish brown (10YR 4/4), moist, clay bridges between sand grains; 10 percent very coarse prominent gray (10YR 6/1), moist, iron depletions in matrix and 10 percent medium distinct strong brown (7.5YR 5/8), moist, iron-manganese masses in matrix; 70 percent rounded 2- to 75-millimeter unspecified fragments; extremely acid, pH 4.0.

TYPE LOCATION: Prince Georges County, Maryland; about 4.75 miles east-northeast of Accokeek and 4.25 miles west-southwest from the intersection of MD Route 5 and Route 373 (Accokeek Road), about 3000 feet west-northwest from the intersection of Garner Road and Route 373 and about 1.75 miles south-southeast from the intersection of Floral Park Road and Danville Road. USGS Piscataway topographic quadrangle; latitude 38 degrees 40 minutes 49.1 seconds N. and longitude 76 degrees 56 minutes 58 seconds W. NAD 83.

RANGE IN CHARACTERISTICS:

Depth to the top of the Argillic: 9 to 14 inches
Depth to the base of the Argillic: 20 to 54 Inches
Bt Thickness: 3 to 45 inches
Solum Thickness: 40 to 120 inches
Depth to Bedrock: Greater than 80 inches
Rock Fragment content: 0 to 70 percent, by volume, in the A horizon, 35 to 75 percent in the upper Bt, and from 15 to 90 percent in the lower Bt and in the C horizon
Soil Reaction: extremely acid to moderately acid, except where limed

RANGE OF INDIVIDUAL HORIZONS:

A or Ap horizon:
Color--hue of 2.5Y or 10YR, value of 3 or 4, and chroma of 1 to 4
Texture (fine-earth fraction)loamy sand, sandy loam, or loam

E horizon (if it occurs):
Color--hue of 2.5Y or 10YR, value of 4 to 7, and chroma of 2 to 4
Texture (fine-earth fraction)loamy sand, sandy loam, or loam

Bt horizon:
Color--hue of 10YR to 5YR, value of 4 to 6, and chroma of 4 to 8
Texture (fine-earth fraction)loamy sand, sandy loam, loam, sandy clay loam, or clay loam

BC horizon:
Color--hue of 10YR to 5YR, value of 4 to 6, and chroma of 2 to 8
Texture (fine-earth fraction)sand, loamy sand, coarse sandy loam, sandy loam, loam, sandy clay loam or clay loam

C horizon (if it occurs):
Color--hue of 10YR to 5YR, value of 4 to 6, and chroma of 2 to 6
Texture (fine-earth fraction)sand, loamy sand or sandy loam. It is stratified.

COMPETING SERIES:
Blackthorn soils have a cambic horizon, are 40 or more inches to the upper boundary of the Bt horizon, and formed in colluvium over residuum.
Elliber soils weathered from cherty limestone and do not have very hard, very firm B horizons.
Gainesboro soils have sedimentary bedrock at less than 40 inches.
Hartleton soils have sola thinner than 40 inches and bedrock at 40 to 65 inches.
Irondale soils are in residuum from igneous rocks, are 20 to 40 inches to bedrock, and have dominantly cobbly textures.
Lew soils have friable B horizons and fragments of greenstone.
Mertz soils have angular rock fragments of chert and sandstone.
Pattenburg soils have sola less than 40 inches thick and friable B horizons.
Trevlac soils have sedimentary bedrock at less than 40 inches.
Weverton soils are in slope creep materials over residuum and are confined to the Blue Ridge Anticlinorium.

GEOGRAPHIC SETTING:
Landscape: Northern Atlantic Coastal Plain
Landform: Interfluves and Knolls
Geomorphic Component: Interfluve and Relict Stream Terraces
Hillslope Profile Position: Summits, Shoulders and Backslopes
Parent Material: Gravelly Fluvial Deposits
Slope: 0 to 60 percent
Elevation: 20 to 400 feet
Frost-free period: 180 to 210 days
Mean Annual Air Temperature: 52 to 57 degrees F
Mean Annual Precipitation: 100 to 125 cm (40 to 50 inches)

GEOGRAPHICALLY ASSOCIATED SOILS:
Aura coarse-loamy particle-size class, has a fragipan, on similar landforms
Chillum fine-silty particle-size class, on similar landforms
Sassafras fine-loamy particle-size class, on similar landforms
Beltsville fine-loamy particle-size class, has a fragipan, on lower landforms

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage Class (Agricultural): Well Drained
Internal Free Water Occurrence: Very Deep and Absent
Index Surface Runoff: Low to very high
Saturated Hydraulic Conductivity Class: Moderately high to moderately low
Permeability Class (obsolete): Moderately slow to slow
Shrink-swell Potential: Low
Flooding Frequency and Duration: None
Ponding Frequency and Duration: None

USE AND VEGETATION:
Major Uses: Gravel Pits, Woodland, Cropland and Urban Use
Dominant Vegetation: Where cultivated tobacco and some truck crops are grown, although the acreage is small. Where wooded, a large part of the acreage is cutover and second growth forest consisting of oaks, Virginia pine, yellow poplar, dogwood, and sweetgum.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: RALEIGH, NORTH CAROLINA
Distribution: Maryland and the District of Columbia
Extent: The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia

SERIES ESTABLISHED: Prince Georges County, Maryland, 1941.

REMARKS: Recent lab data supports the reclassification of the mineralogy from mixed to siliceous. Revision dated 9/2008 updates the mineralogy from mixed to siliceous.
Diagnostic horizons and soil characteristics recognized in this pedon are:
Ochric epipedon--the zone from 0 to 9 inches (Ap horizons)
Argillic horizon--the zone from 9 to 54 inches (Bt horizons)
Series control section--the zone from 0 to 60 inches

ADDITIONAL DATA: Characterization data is available from the NSSL for the following this pedon: 04N1048. This revision updates the mineralogy class from mixed to siliceous. NASIS User Site ID 04MD033036.

---

National Cooperative Soil Survey
U.S.A.