LOCATION CHROME PA+MDEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Hapludalfs
TYPICAL PEDON: Chrome silt loam, 3 to 8 percent slopes, moderately eroded on a southeast facing slope in an early succession woodland. (Colors are for moist interior soil unless otherwise noted.)
Ap--0 to 7 inches; dark olive brown (2.5Y 3/3), light yellowish brown (2.5Y 6/3) dry; silt loam; moderate fine and very fine granular structure; friable, slightly sticky, slightly plastic; many very fine roots throughout; many medium pores; 8 percent subangular channers; slightly acid; abrupt smooth boundary. (3 to 8 inches thick)
Bt--7 to 23 inches; dark yellowish brown (10YR 4/4) channery clay loam; moderate medium subangular blocky structure; friable, moderately sticky, very plastic; common fine roots throughout; common very fine pores ; few distinct clay films on faces of peds; 25 percent subangular channers; moderately acid; clear wavy boundary. (5 to 20 inches thick)
C--23 to 30 inches; dark yellowish brown (10YR 4/4) very channery clay loam; massive; firm, moderately sticky, very plastic; few medium roots throughout; few medium pores; Common distinct clay films on rock fragments; 40 percent channers and 10 percent angular flags; neutral; abrupt irregular boundary. (0 to 20 inches thick)
R--30 inches; dark grayish green (5GY 4/2) exterior, dry serpentine bedrock.
TYPE LOCATION: Delaware County, Pennsylvania; Middletown Township; about .375 miles east-southeast of Lima, along the south side of Route 1 about 3200 feet east of the junction of Route 452 (North Pennell Road) and about 200 feet south of Route 1 and about 125 feet southeast of entrance to Riddle Memorial Hospital off of US Route 1 on a southeast facing slope in a early succession woodland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 10 to 35 inches. Depth to bedrock is 20 to 40 inches. Rock fragments mostly of serpentine range from 0 to 30 percent in the solum and from 10 to 80 percent in the C horizon. Reaction ranges from moderately acid through neutral.
The A horizon has hue of 10YR or 5Y, value and chroma of 3 through 5. Fine-earth texture is loam, silt loam, clay loam or silty clay loam.
The Bt horizon has hue of 7.5YR through 2.5Y, value of 3 through 6 and chroma of 0 through 6. Fine-earth texture is silt clay loam, clay loam, silty clay or clay. Average percent clay in the control section is greater than 35.
The C horizon, where present, has hue of 7.5YR through 5GY, value of 3 through 6 and chroma of 0 through 6. Fine-earth texture is silty clay loam, clay loam, clay, sandy clay loam or sandy loam.
COMPETING SERIES: Briggsville, Edenton, Eldean, Lamoille, Newnata, Paintcreek, Redbrush, Upshur, Woodsfield, and Wynn are in the same family. Briggsville, Eldean, Lamoille, Newnata, Paintcreek, Upshur, Woodsfield and Wynn soils have bedrock at a depth greater than 40 inches. Briggsville soils have carbonates ranging in depths from 20 to 40 inches and have no rock fragments in the control section. Edenton soils have a paralithic contact with calcareous shale and limestone within depths of 20 to 40 and have fragments of glacial gravel. Eldean soils have carbonates within depths of 18 to 36 inches and have dominant rock fragments composed of glacial chert, limestone and shale gravel. Lamoille soils have a rock fragment of more than 35 percent in the lower half of the series control section and have matrix hues of 10YR or 2.5Y in the lower third of the series control section. Newnata soils have a lithic contact with limestone bedrock within depths of 40 to 60 inches. Paintcreek soils have a lithic contact of dolomite bedrock at depths greater than 60 inches. Redbrush soils have dominant rock fragments in the particle control section of quartz and mafic gneiss gravel and cobbles and have a lithic contact with mafic gneiss bedrock within depths of 20 to 40 inches. Upshur soils have hues 5YR or redder in the subsoil and have a sand content of less than 10 percent sand in the particle-size control section. The Woodsfield soils have rock fragments consisting of shale, siltstone and sandstone. Wynn soils have rock fragments composed of glacial limestone gravel and cobbles and have a paralithic contact with calcareous shale and limestone within depths of 20 to 40 inches.
GEOGRAPHIC SETTING: Chrome soils are on nearly level to steep convex uplands of the Northern Piedmont. Slopes range from 0 to 45 percent. They formed in residuum weathered from serpentine, or from other basic rocks high in magnesium. Climate is humid and temperate with mean annual precipitation of 38 to 46 inches; mean annual temperature ranges from 45 to 55 degrees F. The frost-free season ranges from 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Aldino, Baile, Chester, Conowingo, Glenelg, Glenville, Legore, Manor, Montalto, Mount Lucus, Neshaminy, Relay and Watchung soils are on adjacent uplands. Comus, Codorus and Hatboro soils are on nearby floodplains. Aldino and Glenville soils have fragipans. Baile, Watchung and Hatboro soils are poorly drained. Chester, Glenelg, Comus, Legore, Manor, Montalto, Neshaminy and Relay soils have bedrock deeper than 40 inches. Conowingo soils are somewhat poorly drained. Mount Lucus and Codorus soils are moderately well and somewhat poorly drained.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Runoff is medium to very rapid. Saturated hydraulic conductivity is moderately high to high.
USE AND VEGETATION: Typical vegetation is described as pine-savannah. Unfavorable physical and chemical properties of serpentine soils, such as shallowness, stoniness, low available water capacity and high levels of iron and magnesium and low levels of silica and calcium make these soils unfavorable for plant growth, especially in mixed hardwoods, resulting in a unique prairie-pine ecosystem termed barrens". In some instances these soils may contain plant toxic levels of nickel, chromium and cobalt (Mansburg, 1984). Approximately 90 percent of the Chrome soils are in woodland or in pasture. About 10 percent of the soils are cultivated.
DISTRIBUTION AND EXTENT: Maryland and Pennsylvania. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Montgomery County, Maryland, 1959.
REMARKS: Previously updated in 3/90. The 4/2004 EJM-EAW revision added superactive cation-exchange activity class. Extensive revisions in 10/2008 as it was re-described for updating needs. User pedon ID in NASIS: 07PA045001. This series is proposed to be listed as a rare or unique soil series.
Diagnostic horizons and other features recognized in this pedon are:
a. Ochric epipedon - the zone from the surface to a depth of 7 inches (Ap horizon).
b. Argillic horizon - the zone from about 7 to 23 inches (Bt horizon).
c. Lithic Contact 30 inches (R horizon)