LOCATION ARMAGH PA+MD
Established Series
Rev. DRS-AWD
04/2025
ARMAGH SERIES
The Armagh series consists of deep and very deep, poorly drained soils formed in residuum from acid shale interbedded with siltstone and sandstone. They are on broad ridgetops and benches. Slopes range from 0 to 8 percent. Saturated hydraulic conductivity is low. Mean annual precipitation is 1066 millimeters (42 inches). Mean annual temperature is 10.5 degrees C (51 F).
TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Endoaquults
TYPICAL PEDON: Armagh silt loam, in an area of Armagh silt loam, 0 to 8 percent slopes in woodland. (Colors are for moist soil unless otherwise noted.)
Oe--0 to 3 centimeters; moderately decomposed organic matter.
A1--3 to 8 centimeters; black (10YR 2/1) silt loam; weak very fine granular structure; friable, nonsticky and nonplastic; 2 percent coarse fragments; very strongly acid; clear wavy boundary.
A2--8 to 13 centimeters; dark gray (10YR 4/1) silt loam; weak very fine and fine granular structure; friable, slightly sticky and nonplastic; common fine distinct gray (N 6/0) iron depletions and few prominent yellow (10YR 7/8) masses of iron accumulation; 5 percent coarse fragments; very strongly acid; clear wavy boundary. (Combined thickness of A or Ap horizons is 5 to 30 centimeters thick)
BEg--13 to 28 centimeters; gray (10YR 6/1) silty clay loam; weak fine subangular blocky structure; friable, moderately sticky and moderately plastic; common medium faint gray (N 6/0) iron depletions and common medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; 5 percent coarse fragments; strongly acid; clear wavy boundary.
Btg1-- 28 to 51 centimeters; light gray (10YR 7/1) silty clay loam; moderate medium subangular blocky structure; friable, moderately sticky and moderately plastic; few faint light gray (10YR 7/2) clay films on ped faces; common medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; 5 percent coarse fragments; strongly acid; clear wavy boundary
Btg2--51 to 79 centimeters; light gray (10YR 7/1) silty clay loam; weak very coarse prismatic structure parting to moderate medium subangular blocky; firm, moderately sticky and moderately plastic; few faint light gray (10YR 7/2) clay films on ped faces; few prominent black (N 2/0) concretions; many medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; 5 percent coarse fragments; strongly acid; clear wavy boundary.
Btg3--79 to 109 centimeters; light gray (10YR 7/1) silty clay loam; weak very coarse prismatic structure parting to moderate medium subangular blocky; firm, moderately sticky and moderately plastic; few faint light gray (10YR 7/2) clay films on ped faces; few prominent black (N 2/0) concretions; many medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; 10 percent coarse fragments; strongly acid; clear wavy boundary. (Combined thickness of the Btg horizon is 60 to 90 centimeters.)
Cg--109 to 155 centimeters; light gray (10YR 7/1) very channery silty clay loam; massive; firm, moderately sticky and moderately plastic; few prominent black (N 2/0) concretions; many medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; 35 percent coarse fragments; strongly acid
TYPE LOCATION: Union Township, Clearfield County, 0.8 kilometers north of Home Camp, 275 meters east of the intersection of Township route 421 and Township road 512, 10 meters north of the road in a wooded area; USGS Sabula, PA topographic quadrangle; latitude 41.127200 and longitude -78.640622 (WGS 84).
RANGE IN CHARACTERISTICS: Solum thickness ranges from 75 to 130 centimeters. Depth to shale or sandstone bedrock is 100 to 183 centimeters. Rock fragments range from 0 to 15 percent in the upper part of the solum, 5 to 15 percent in the lower part of the solum, and 10 to 80 percent in the C horizon. Reaction is strongly or very strongly acid throughout unless limed. Kaolinite and illite are the dominant clay minerals with detectable amounts of chlorite and vermiculite.
The A or Ap horizon has hue of 10YR or 2.5Y, value of 2 through 5, and chroma of 1 or 2. It is silt loam or silty clay loam in the fine-earth fraction.
Some pedons have E or BE horizons up to 15 centimeters thick with hue of 10YR or 2.5Y, value of 4 through 6, and chroma of 1. It is silt loam or silty clay loam in the fine-earth fraction.
The Btg horizon is neutral or has hue of 7.5YR through 5Y, value of 4 through 7, and chroma of 0 through 2. It has distinct or prominent redoximorphic features. It ranges from silty clay loam to clay with channery analogues in the lower part.
Some pedons have a BC horizon with colors and textures similar to the C horizon.
The C horizon has hue of 7.5YR through 5Y, value of 5 or 6, and chroma of 1 through 8, and is mottled. It ranges from loam to silty clay in the fine-earth fraction.
COMPETING SERIES: The
Delila,
Lenni, and
Purdy series are in the same family. Delila soils formed in local alluvium from felsic igneous and metamorphic rocks in the
Piedmont. Lenni soils formed in clayey eolian deposits underlain by sandy fluviomarine deposits on broad interstream divides, and in shallow depressions primarily in the northern Coastal Plain. Purdy soils formed in slackwater deposits on terraces and have less than 5 percent rock fragments in the lower part of the series control section.
GEOGRAPHIC SETTING: Armagh soils are on broad ridgetops and benches. Slopes range from 0 to 8 percent. These soils developed in materials weathered from acid gray shale, with some interbedded siltstone and sandstone. The mean annual precipitation ranges from 890 to 1220 millimeters, and mean annual temperature ranges from 7.2 to 13.8 degrees C.
GEOGRAPHICALLY ASSOCIATED SOILS: Armagh soils are in a drainage sequence with the moderately well drained
Wharton soils and the somewhat poorly drained
Cavode soils. All of these soils average less than 35 percent clay in the control section. Other associated soils include the
Brinkerton,
Ernest,
Gilpin, and
Rayne soils. Brinkerton and Ernest formed in colluvium and have a fragipan. Gilpin and Rayne soils are well drained and lack redoximorphic features.
DRAINAGE AND PERMEABILITY: Poorly drained. Saturated hydraulic conductivity is low to very low and some areas are ponded during wet periods.
USE AND VEGETATION: About 35 percent of the area is in cropland, pasture, or is idle. The remaining 65 percent is in woodland consisting of mixed northern hardwoods dominantly in ash, tulip poplar, and red maple.
DISTRIBUTION AND EXTENT: Appalachian Plateau of western Pennsylvania and western Maryland. MLRA's 124, 126, 127, and 147. The series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Clarion County, Pennsylvania, 1940.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
a. Ochric epipedon - the zone from the surface of the soil to a depth of 28 centimeters (A and BEg horizons).
b. Argillic horizon - the zone from 28 to 109 centimeters (Btg horizons).
Available laboratory data does not support the presence of an argillic horizon. Further study or sampling is needed.
National Cooperative Soil Survey
U.S.A.