LOCATION SOCO NC+TNEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, active, mesic Typic Dystrudepts
TYPICAL PEDON: Soco channery loam on a 48 percent southeast facing mountain side slope--forested. (Colors are for moist soil unless otherwise stated).
0i--0 to 2 inch; partially decomposed organic matter and leaves, twigs, and roots.
A--2 to 6 inches; very dark grayish brown (10YR 3/2) channery loam, brown (10YR 4/3) dry; weak fine granular structure; very friable; many fine and medium roots; 5 percent by volume flagstones that are mostly metasandstone and 15 percent by volume phyllite channers; common fine flakes of mica; very strongly acid; clear wavy boundary. (2 to 10 inches thick)
Bw1--6 to 15 inches; strong brown (7.5YR 4/6) fine sandy loam; weak medium subangular blocky structure; friable; 5 percent by volume phyllite channers; common fine flakes of mica; strongly acid; clear wavy boundary.
Bw2--15 to 26 inches; dark yellowish brown (10YR 4/6) fine sandy loam; weak fine subangular blocky structure; friable; 5 percent by volume phyllite channers; common fine flakes of mica; very strongly acid; gradual wavy boundary. (Combined thickness of the Bw horizon is 15 to 34 inches.)
BC--26 to 34 inches; yellowish brown (10YR 5/4) channery fine sandy loam; massive; friable; 20 percent by volume weathered phyllite channers; common fine flakes of mica; very strongly acid; gradual wavy boundary. (0 to 10 inches thick)
C--34 to 37 inches; brown (10YR 5/3), gray (10YR 6/1), and black (10YR 2/1) saprolite that has a channery fine sandy loam texture; friable; 25 percent by volume weathered phyllite channers; common fine flakes of mica; very strongly acid; clear wavy boundary. (0 to 12 inches thick)
Cr--37 to 62 inches; multicolored weathered metasandstone and thinly bedded phyllite; few seams of multicolored fine sandy loam in cracks; partly consolidated but can be dug with difficulty with a hand tools.
TYPE LOCATION: Jackson County, North Carolina; 10 miles northeast of Cherokee on U.S. Highway 19 to Soco Gap; 5 miles northwest on Blue Ridge Parkway to Barnett Knob Fire Tower Road; 500 feet southwest on Fire Tower Road; 100 feet south of road in woods, USGS Bunches Bald Quadrangle; lat. 35 degrees, 31 minutes, 24 seconds N., and long. 83 degrees, 37 minutes, 48 seconds W.; NAD 27.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 15 to 39 inches. Depth to a paralithic contact at the upper boundary of the Cr horizon ranges from 20 to 40 inches below the soil surface. Depth to a lithic contact is more than 40 inches. Reaction is extremely acid to strongly acid unless limed. Content of rock fragments range from 0 to 35 percent throughout. . Content of flakes of mica is none to common throughout.
The A horizon has hue of 7.5YR to 2.5Y, value of 2 to 5, and chroma of 1 to 6. Where value is 3 or less , this horizon is less than 7 inches thick. The A horizon is loam, fine sandy loam, or silt loam in the fine-earth fraction.
The AB or BA horizon, where present, has hue of 7.5YR to 2.5Y, value 4 to 6, and chroma of 3 to 8, The AB or BA horizon is loam, fine sandy loam, sandy loam, very fine sandy loam, or silt loam in the fine-earth fraction.
The Bw horizon has hue of 5YR to 2.5Y, value of 4 to 6, and chroma of 3 to 8. They are loam, fine sandy loam, sandy loam, very fine sandy loam, or silt loam in the fine-earth fraction.
The BC horizon, where present, has color and texture similar to the Bw horizon.
The C horizon, if present, has the same colors as the Bw or is multicolored saprolite weathered from coarse grained metasedimentary rocks. It has a texture of loamy fine sand, loamy sand, sandy loam, fine sandy loam, loam, or silt loam in the fine-earth fraction.
The Cr horizon is multicolored, weathered coarse grained metasedimentary rock that is partly consolidated but can be dug with difficulty with a hand tools. The upper boundary is considered as a paralithic contact where root spacing is greater than 4 inches.
COMPETING SERIES: These are the Ashe, Brookfield, Buladean, Cardigan, Charlton, Chestnut, Delaware, Ditney, Dutchess, Edneyville, Foresthills (T), Gallimore, Greenbelt (T), Lordstown, Newport, Riverhead, St. Albans, Stecoah, Steinsburg, Wakeman, and Yalesville series. Ashe, Cardigan, Ditney, Lordstown, Steinsburg, Wakeman, and Yalesville soils have lithic contact within depths of 20 to 40 inches. Brookfield soils are very deep and formed in micaceous till. Buladean and Stecoah soils have paralithic contact at depths of 40 to 60 inches. Charlton soils are very deep and formed in glacial till derived mainly from schist, gneiss, or granite. Chestnut soils formed in residuum weathered from high-grade metamorphic rocks and contain fragments of those rocks. Delaware soils are very deep and formed in postglacial alluvium, mainly from areas of sandstone, shale, and siltstone. Dutchess and St. Albans soils are very deep and contain coarse fragments of sedimentary rocks such as sandstone and shale. Edneyville soils are very deep and formed in residuum weathered from high-grade metamorphic rocks and contain fragments of those rocks. Foresthills (T) and Greenbelt (T) soils are very deep and have mantles of humanly transported materials. Gallimore soils are very deep and formed in loamy over sandy outwash on outwash plains. Newport soils have C horizons of dense glacial till. Riverhead soils have a lithologic discontinuity in the upper 40 inches.
GEOGRAPHIC SETTING: Soco soils are on gently sloping to very steep ridges and side slopes of the Blue Ridge (MLRA 130). Elevation ranges from 1500 to 4800 feet. Slope is commonly between 30 and 70 percent but ranges from 2 to 95 percent. Soco soils formed in residuum that is affected by soil creep in the upper part, and is weathered from low-grade metasedimentary rocks such as metasandstone or metagraywacke, occasionally interbedded with phyllite or slate. Occasionally they form from residuum weathered from quartzite with a high content of feldspar. Mean annual temperature is 53 degrees F. and mean annual precipitation is about 41 inches near the type location. Mean annual rainfall ranges up to about 75 inches on this soil in Jackson County, North Carolina.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the competing Ditney , Maymead, and Stecoah soils, these include the Brasstown, Brookshire, Cataska, Cheoah, Citico, Harmiller, Jeffrey, Junaluska, Lonon, Northcove, Santeetlah, Shinbone, Spivey, Sylco, Tsali, and Unicoi soils. All these soils are on ridges and side slopes except for Brookshire, Citico, Lonon, Maymead, Northcove, Santeetlah, and Spivey soils, which are in coves. Citico soils are fine-loamy and Northcove and Spivey soils are very deep and are loamy-skeletal. Brasstown, Harmiller, Junaluska, Lonon, Shinbone, and Tsali soils have argillic horizons. Brookshire, Cheoah, Jeffrey, Santeetlah, and Spivey soils have umbric epipedons or ochric epipedons with value 3 or less at least 7 inches thick. Cataska and Sylco soils are loamy-skeletal. Marbleyard soils are loamy-skeletal and McCamy soils are fine loamy. Both have a siliceous mineralogy and have a lithic contact at 20 to 40 inches below the soil surface. Unicoi soils are 7 to 20 inches to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; very little runoff where forest litter has not been disturbed. Medium to very rapid runoff where litter has been removed; moderately rapid permeability.
USE AND VEGETATION: Most of the soil is in forest. Common trees are chestnut oak, hickory, Virginia pine, black oak, scarlet oak, eastern white pine, and white oak. . The understory includes rhododendron, mountain laurel, sassafras, flowering dogwood, sourwood, American chestnut sprouts, blueberry, and buffalo nut. A small acreage is cleared and used for pasture, hay and occasionally small grain and Christmas trees.
DISTRIBUTION AND EXTENT: Blue Ridge (MLRA 130) of North Carolina Georgia, Tennessee, and Virginia. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: McDowell County, North Carolina; 1989. The name is from Soco Gap near the type location in Jackson County.
REMARKS: The Soco series was formerly included with the Sylco series. However, Soco soils are not skeletal. The 2/99 revision updated the classification to the 8th Edition of Keys to Soil Taxonomy. This soil is placed in the active CEC activity class based on comparison with associated soils such as Stecoah.
This series has the following diagnostic horizons and features:
Ochric epipedon - the zone from the surface of the soil to a depth of 6 inches. (Oi and A horizons)
Cambic horizon - the zone from a depth of 6 to 26 inches. (Bw1 and Bw2 horizons)
Paralithic contact - the occurrence of weathered bedrock at a depth of 37 inches
(the upper boundary of the Cr horizon).
MLRA = 130 SIR = NC0180