LOCATION DORMONT PA+OH WVEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Oxyaquic Hapludalfs
TYPICAL PEDON: Dormont silt loam, idle. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 11 inches; brown (10YR 4/3) silt loam; moderate fine granular structure; friable, slightly sticky, non-plastic; common very fine and fine roots throughout; 5 percent shale fragments; slightly acid; abrupt wavy boundary. (2 to 10 inches thick)
Bt1--11 to 21 inches; strong brown (7.5YR 5/6) silt loam; strong medium subangular blocky structure; firm, slightly sticky, slightly plastic; few very fine roots between peds; 10 percent discontinuous faint yellowish brown (10YR 5/4), moist, clay films on faces of peds; 5 percent shale fragments; moderately acid; clear wavy boundary. (5 to 10 inches)
Bt2--21 to 31 inches; reddish yellow (7.5YR 6/6) silty clay loam; moderate medium subangular blocky structure; firm, moderately sticky, moderately plastic; few very fine roots between peds; 30 percent discontinuous distinct yellowish brown (10YR 5/6), moist, clay films on faces of peds and in pores; 8 percent shale-siltstone fragments; moderately acid; clear wavy boundary. (10 to 30 inches)
Bt3--31 to 46 inches; pale brown (10YR 6/3) silty clay loam; strong medium and coarse subangular blocky structure; firm, moderately sticky, moderately plastic; 40 percent continuous distinct clay films on faces of peds and in pores; 5 percent medium irregular black (5YR 2/1) iron-manganese concretions around rock fragments; common fine distinct irregular brownish yellow (10YR 6/6) masses of iron accumulation and many fine and medium distinct irregular gray (10YR 6/1) iron depletions; 18 percent shale-siltstone fragments; moderately acid; gradual wavy boundary. (10 to 30 inches thick)
Bt4--46 to 62 inches; light yellowish brown (10YR 6/4) silty clay loam; strong medium and coarse subangular blocky structure; firm, slightly sticky, slightly plastic; 20 percent continuous distinct clay films on faces of peds and in pores; 10 percent medium irregular black (5YR 2/1) iron-manganese concretions around rock fragments; many medium distinct irregular yellowish brown (10YR 5/6) masses of iron accumulation and many medium prominent irregular gray (10YR 6/1) iron depletions; 40 percent shale-siltstone fragments; moderately acid; gradual wavy boundary. (10 to 30 inches thick)
BC--62 to 75 inches; light yellowish brown (10YR 6/4) silty clay loam; weak coarse subangular blocky structure; firm, slightly sticky, slightly plastic; 10 percent discontinuous faint clay films on faces of peds; 5 percent medium irregular black (5YR 2/1) iron-manganese concretions around rock fragments; many fine distinct irregular strong brown (7.5YR 5/6) masses of iron accumulation and common fine prominent light gray (10YR 7/1) iron depletions; 80 percent shale-siltstone fragments; moderately acid. (0 to 15 inches thick)
TYPE LOCATION: Westmoreland County, Pennsylvania; Rostraver Township, 0.75 miles SE of Sweeneys Crossroads, 530 feet NE of PA 51 in a field. Latitude: 40 degrees 10 minutes 17.00 seconds north; Longitude: 79 degrees 47 minutes 36.00 seconds west.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 36 to 65 inches. Depth to bedrock is 48 to 80 inches. Rock fragments of siltstone, shale, or sandstone range from 0 to 15 percent by volume in the A horizon, from 2 to 15 percent in the upper part of the B horizon, from 5 to 30 percent in the lower part of the B horizon, and from 5 to 50 percent in the C horizon. Reaction, where unlimed, ranges from very strongly acid through slightly acid in the upper part of the solum and is strongly acid through slightly alkaline in the lower part of the solum and C horizon.
The Ap horizon has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 2 to 4. Texture is silt loam or silty clay loam in the fine-earth fraction. Undisturbed pedons have thin dark A horizon.
Some pedons have thin E horizons.
The BA or BE horizon, where present, has colors and textures similar to the upper part of the Bt horizon.
The upper part of the Bt horizon has a hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 4 to 6. Texture is silt loam or silty clay loam in the fine-earth fraction. The lower part of the Bt horizon has a hue of 7.5YR to 5Y and N, value of 4 to 6, and chroma of 0 through 6. Redoximorphic features are in shades of yellow, brown, red, or gray. Redoximorphic depletions of 2 chroma or less are within 36 inches of the surface. Texture is silt loam, silty clay loam or silty clay in the fine-earth fraction.
The BC horizon and C horizon (where present) horizon have colors similar to the lower part of the Bt horizon. Texture ranges from silt loam, silty clay loam or silty clay in the fine-earth fraction.
COMPETING SERIES: These are the Nessel and Bassett series in the same family. Bassett and Nessel soils all are formed from glacial till and lack flat, angular or subangular fragments of shale and sandstone in the solum.
GEOGRAPHIC SETTING: Dormont soils are on hill summits and backslopes. Slopes range from 0 to 50 percent. They formed in colluvium and residuum from nonacid shale and siltstone, with some thin beds of limestone and sandstone. The climate is humid and temperate. Mean annual precipitation ranges from 36 to 45 inches; mean annual temperature ranges from 48 to 55 degrees F; and the frost free season ranges from 140 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clarksburg, Culleoka, Faywood, Guernsey, Library, Lowell, and Westmoreland series. Faywood, Guernsey, Library, and Lowell soils all have more than 35% clay in the control section. Culleoka and Westmoreland soils lack redoximorphic features in the solum. Culleoka soils also have bedrock within 40 inches. Clarksburg soils have a fragipan that Dormont soils lack.
DRAINAGE AND PERMEABILITY: Moderately well drained. Surface runoff is medium to rapid. Permeability is slow or moderately slow.
USE AND VEGETATION: Most of these soils on gentler slopes have been cleared and farmed but many areas are now used for pasture or are idle. Some areas are wooded, dominantly with mixed oaks.
DISTRIBUTION AND EXTENT: Southwestern Pennsylvania, West Virginia, and possibly southeastern Ohio. MLRA's 125 and 126 Extent is large.
MLRA OFFICE RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Allegheny County, Pennsylvania, 1973.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from the surface of the soil to a depth of about 12 inches (Ap, Ap1, Ap2, and BA horizons).
2. Argillic horizon - the zone from 12 to 48 inches (Bt horizon).