LOCATION ALARKA NC+TN
Established Series
DJT,MS,HCD
03/2022
ALARKA SERIES
The Alarka series consists of very deep, poorly drained soils in hanging coves of intermediate mountains of the Southern Blue Ridge (MLRA 130B). They formed in loamy colluvium and underlying alluvium. The elevation ranges from 2,500 feet to 5,000 feet. Slope ranges from 3 to 15 percent.
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, active, mesic Aeric Epiaquults
TYPICAL PEDON: Alarka mucky fine sandy loam on a 4 percent slope, elevation 4,200 feet -- rhododendron thicket; south of Whittier in Alarka Creek watershed. (Colors are for moist soils unless otherwise noted.)
Oe--0 to 3 inches; moderately decomposed plant material; many very fine to very coarse roots; extremely acid; clear wavy boundary.
Oa1--3 to 7 inches; highly decomposed plant material; many fine and coarse roots; ultra acid; clear irregular boundary.
Oa2--7 to 10 inches; highly decomposed plant material, common fine to coarse roots; ultra acid; clear irregular boundary. (combined thickness of the O horizon is 4 to 10 inches)
Btg--10 to 13 inches; brown (7.5YR 5/2) loam; weak medium subangular blocky structure; friable, slightly sticky, slightly plastic; few medium and coarse roots; few faint clay films on ped faces; many medium and coarse prominent strong brown (7.5YR 5/8) irregularly shaped soft masses of iron accumulations throughout; black (10YR 2/1) organic matter accumulations 1 to 5 cm thick in root channels throughout 10 percent of the horizon; few fine mica flakes throughout; extremely acid; clear wavy boundary.
Bt--13 to 21 inches; yellowish brown (10YR 5/8) loam; weak medium subangular blocky structure; friable, slightly sticky, slightly plastic; few coarse roots; few faint clay films on ped faces; few fine prominent red (2.5YR 4/6) irregularly shaped soft masses of iron accumulations throughout; many medium and coarse dark grayish brown (10YR 4/2) iron depletions throughout; black (10YR 2/1) organic matter accumulations 1 to 5 cm thick in root channels throughout 10 percent of the horizon; few fine mica flakes throughout; extremely acid; clear wavy boundary. (Combined thickness of the Bt horizon is 10 to 24 inches.)
Cg--21 to 36 inches; light brownish gray (2.5Y 6/2) very fine sandy loam; massive; friable; common medium and coarse distinct dark yellowish brown (10YR 4/6) redoximorphic irregularly shaped soft masses of iron accumulations lining pores; 5 percent gravel by volume; very strongly acid; abrupt wavy boundary. (0 to 16 inches.)
2C--36 to 60 inches; yellowish brown (10YR 5/6), red (2.5YR 5/8), and strong brown (7.5YR 5/6) very gravelly loamy sand; massive; loose; 39 percent gravel, 5 percent cobbles, 15 percent stones by volume; very strongly acid .
TYPE LOCATION: Swain County, North Carolina; Alarka Creek; USGS topographic quadrangle Greens Creek; south of Whittier in Alarka Creek watershed; from Whittier on Secondary Road 1173 to Secondary 1193; west on Secondary Road 1193 to Secondary Road 1177, south on Secondary Road 177 to USFS Road 86; south on USFS Road 86 to Wesser Gap; about 1.1 miles from Wesser Gap on USFS Road 86; west of USFS Road 150 feet along small branch. Latitude 35 degrees, 20 minutes, 6 seconds N., Longitude 83 degrees, 21 minutes, 18 seconds W. NAD 27.
RANGE IN CHARACTERISTICS: Depth to bedrock is greater than 5 feet. Depth to the 2C horizon that contains more than 35 percent by volume gravel, cobbles, and /or stones is 20 to 40 inches. Content of mica flakes is few or common. Reaction is ultra acid to very strongly acid depending upon vegetative cover.
The O horizons range from 4 to 10 inches thick and may appear as a thick root mat. Extent and type of vegetative cover influences the thickness of the O horizons.
The A horizon, where present, has a hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 to 3. The texture is loam, fine sandy loam, or sandy loam.
The Btg horizon has a hue of 7.5YR to 2.5Y, value of 2 to 5, and chroma of 1 or 2. The texture of the Btg horizon is sandy loam, loam, sandy clay loam, or clay loam
The Bt horizon has a hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8. The texture of the Bt horizon is sandy loam, loam, sandy clay loam, or clay loam.
The Cg horizon, where present, has a hue of 10YR or 2.5 Y, value of 2 to 6, and chroma of 1 or 2. The texture of the Cg horizon is sandy loam, fine sandy loam, very fine sandy loam, or loam. Some pedons may have a C horizon that does not have a reduced matrix. This horizon has a hue of 5YR to 10YR, value of 4 or 5, and chroma of 3 to 6.
The 2C horizon has hue of 10YR or 7.5YR, value of 5 or 6 and chroma of 6 or 8. Some pedons may not have a dominate matrix color and be mottled in shades of yellow, brown, red or gray. Texture is loamy sand, sandy loam, or fine sandy loam.
COMPETING SERIES: There are no known competing soil series.
GEOGRAPHIC SETTING: Alarka soils are on gently or strongly sloping colluvial footslopes in hanging coves in the Southern Blue Ridge (MLRA 130B). Normally located in the upper reaches of watersheds, these hanging coves occur where the landscape is relatively wide for some distance before narrowing at a lower elevation. Seeps and springs also are common features of these areas. Alarka soils formed in colluvium and the underlying skeletal alluvial strata deposited by high energy flooding events. Microrelief is hummocky on the gently sloping portions of these hanging coves, and Alarka soils are commonly on the higher portions of these areas. The elevation ranges from 2,500 feet to 5,000 feet. Near the type location, mean annual temperature is 55 degrees F., and mean annual precipitation is 70 inches. Slope ranges from 3 to 15 percent.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Cataloochee,
Cheoah,
Chestnut,
Cullasaja,
Edneyville,
Guyot,
Jeffrey,
Oconaluftee,
Plott,
Santeetlah,
Soco,
Spivey,
Stecoah,
Tuckasegee,
Wayah,
Wesser,
Whiteoak, and
Whiteside series. Of these, only Wesser and Whiteside soils are found in hanging coves. Wesser soils are very poorly drained, in a sandy or sandy skeletal particle size family, and are on lower, nearly level parts of hummocks. Whiteside soils are moderately well drained and on similar landscapes in more sloping parts of hanging coves. Cataloochee, Guyot, Oconaluftee, and Wayah soils are on ridges and side slopes in frigid temperature regimes. Cheoah, Chestnut, Edneyville, Jeffrey, Plott, Soco, and Stecoah soils are on ridges and side slopes in mesic temperature regimes. Cullasaja, Santeetlah, Spivey, Tuckasegee, and Whiteoak soils are well drained and on benches, foot slopes, toe slopes, drainageways, and fans in nearby coves, which are not covered in rhododendron thickets.
DRAINAGE AND PERMEABILITY: Poorly drained; moderately slow or slow permeability in the upper horizons and moderately rapid permeability in the lower horizons. Permeability in the upper part is largely influenced by the contact between the thick organic mat with the mineral soil. At this contact, the differences in pore size distribution between these two layers result in a slowing of water movement. Redoximorphic features from groundwater moving through the lower part are not as pronounced due to the skeletal nature of the underlying strata. These two conditions commonly result in an oxidized matrix within the Bt horizon.
USE AND VEGETATION: All of the acreage is in woodland, primarily in National Forest or in the Great Smoky Mountains National Park. These areas are of great habitat importance to amphibians, especially salamanders. The dominant vegetative cover is rhododendron thicket, which provides shading and moisture retention for the development of the thick organic mat. Evergreen trees such as hemlock, white pine, and red spruce are common overstory species.
DISTRIBUTION AND EXTENT: The Southern Blue Ridge (MLRA 130B) of North Carolina and Tennessee. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Great Smoky Mountain National Park 2007.
REMARKS: Soils of the Alarka series were mapped as part of the Humaquepts map unit in the Haywood County Area, NC Soil Survey. However, due to the small size and variability of the map units, no series were established. Alarka soils are mainly mapped in a complex with the very poorly drained Wesser series. Some soils may have a frigid temperature regime. However, the small extent and unique properties of these soils do not warrant a separation of series based on temperature at this time. This soil was sampled and analyzed by the National Soil Survey Laboratory in Lincoln, NE; Sample number S99NC-173-001.
Revisions made 9/07(HCD) adjusted OSD to reflect Lab Data
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon 0 to 10 inches (Oe, Oa, and A horizons)
Argillic horizon 10 to 21 inches (Btg and Bt horizons)
Aeric subgroup feature 13 to 21 inches (Bt horizon) the zone which has matrix chroma of more than 3 in one or more horizons between 10 inches from the mineral soil surface and 30 inches.
National Cooperative Soil Survey
U.S.A.