LOCATION SILOAM NC+VA
Established Series
RJL-DCC/Rev. JAK/DTA
06/2026
SILOAM SERIES
MLRA(s): 136 (mesic part)
Soil Survey Regional Office (SSRO) Responsible: Southeast
Depth Class: Shallow
Agricultural Drainage Class: Well drained
Index Surface Runoff: Medium to very high
Saturated Hydraulic Conductivity Class: Moderately high
Shrink-Swell Potential: Moderate
Landscape: Piedmont uplands
Landform: Interstream divides, ridges, and side slopes
Parent Material: Residuum weathered from mafic metamorphic or igneous rock
Slope: 2 to 60 percent
Elevation (type location): 286 meters (940 feet)
Frost Free Period (type location): 174 days
Mean Annual Air Temperature (type location): 14 degrees C (57 degrees F)
Mean Annual Precipitation (type location): 1168 millimeters (46 inches)
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Typic Hapludalfs
TYPICAL PEDON: Siloam fine sandy loam (in an area of Siloam-Zion complex, 6 to 15 percent slope), on a convex 7 percent slope in hayland. (Colors are for moist soil unless otherwise indicated.)
Ap--0 to 20 centimeters (0 to 8 inches); dark yellowish brown (10YR 3/4) fine sandy loam; weak medium granular structure; friable, nonsticky, nonplastic; many fine roots throughout; common fine tubular pores; 15 percent fine mica flakes throughout; 10 percent 2- to 75-millimeter quartz fragments; neutral, pH 7.0, Hellige-Truog; 15 percent coarse distinct dark yellowish brown (10YR 4/4) bodies of B horizon soil material throughout; clear wavy boundary. (5 to 25 centimeters (2 to 10 inches) thick)
Bt--20 to 33 centimeters (8 to 13 inches); dark yellowish brown (10YR 4/6) sandy clay loam; moderate coarse angular blocky structure; friable, moderately sticky, moderately plastic; common fine roots throughout; few fine tubular pores; 10 percent discontinuous distinct yellowish brown (10YR 5/4) clay films on vertical faces of peds; 10 percent fine distinct irregular yellowish brown (10YR 5/8) masses of oxidized iron between peds; 15 percent fine mica flakes throughout; 5 percent 2- to 75-millimeter gneiss fragments and 5 percent 2- to 75-millimeter quartz fragments; neutral, pH 7.0, Hellige-Truog; 15 percent moderate-continuity distinct dark brown (10YR 3/3) fillings of A horizon soil material in old root channels and between peds; clear irregular boundary. (8 to 38 centimeters (3 to 15 inches) thick)
Bt/C--33 to 38 centimeters (13 to 15 inches); 80 percent dark yellowish brown (10YR 4/6) sandy clay loam; moderate coarse angular blocky structure; friable, moderately sticky, moderately plastic; common fine roots throughout; few fine tubular pores; 10 percent discontinuous distinct yellowish brown (10YR 5/4) clay films on vertical faces of peds; 10 percent fine distinct irregular yellowish brown (10YR 5/8) masses of oxidized iron between peds; 15 percent fine mica flakes throughout; 5 percent 2- to 75-millimeter quartz fragments and 5 percent 2- to 75-millimeter gneiss fragments; neutral, pH 7.0, Hellige-Truog; coarse soil peds part along relic rock fractures; 15 percent moderate-continuity distinct dark brown (10YR 3/3) fillings of A horizon soil material in old root channels and between peds (Bt part); 20 percent pockets of massive; friable; green, brown, gray, white, and black loamy saprolite (C part); abrupt irregular boundary. (0 to 25 centimeters (0 to 10 inches) thick)
Cr--38 to 66 centimeters (15 to 26 inches); soft gneiss bedrock, fractured at intervals of 10 centimeters (4 inches)to less than 46 centimeters (18 inches); weakly cemented; moderate excavation difficulty; abrupt irregular boundary.
R--66 centimeters (26 inches); hard gneiss bedrock, fractured at intervals of 10 centimeters (4 inches)to less than 46 centimeters (18 inches); very strongly cemented; very high excavation difficulty.
TYPE LOCATION: Surry County, North Carolina; from the intersection of Secondary Roads 1003 and 2085, southeast 0.8 mile on Secondary Road 1003, east 0.6 mile of Secondary Road 1003, in fescue hayland; USGS Siloam, North Carolina topographic quadrangle.
Latitude--36.3029
Longitude-- -80.5722
Datum--WGS84
RANGE IN CHARACTERISTICS:
Depth to top of Argillic horizon: 2 to 25 centimeters (1 to 10 inches)
Depth to base of Argillic horizon: 25 to 51 centimeters (10 to 20 inches)
Depth to bedrock: 25 to 51 centimeters (10 to 20 inches to soft bedrock), 51 to 102 centimeters (20 to 40 inches) to hard bedrock
Depth to Seasonal High Water Table: Greater than 152 centimeters (60 inches)
Rock Fragment Content: 0 to 35 percent, by volume throughout; mostly quartz or gneiss gravel, cobbles, and stones
Mica Content: 0 to 20 percent, by volume throughout
Soil Reaction: Strongly acid to slightly acid in the upper horizons and moderately acid to mildly alkaline in the lower horizons
Other Features: 0 to 20 percent, by volume, dark manganese concretions or nodules throughout
RANGE OF INDIVIDUAL HORIZONS:
Ap horizon or A horizon:
Color--hue of 7.5YR to 5Y, value of 3 to 5, chroma of 2 to 6
Texture (fine-earth fraction)--sandy loam, fine sandy loam, or loam. Eroded phases include sandy clay loam or clay loam.
E horizon (if it occurs):
Color--hue of 7.5YR to 2.5Y, value of 4 to 6, chroma of 3 to 6
Texture (fine-earth fraction)--sandy loam, fine sandy loam, or loam
Bt horizon:
Color--hue of 5YR to 2.5Y, value of 4 to 6, chroma of 4 to 8
Texture (fine-earth fraction)--loam, sandy clay loam, clay loam, or clay
Non-redoximorphic mottles (if they occur)--masses in shades of black, green, gray, or white, mostly saprolite.
Bt/C horizon:
Bt part--same properties as Bt horizon
C part--same properties as C horizon
C horizon (if it occurs):
Color--hue of 5YR to 5Y, value of 4 to 6 chroma of 4 to 8, or variegated shade of these colors
Texture (fine-earth fraction)--sandy loam, fine sandy loam, or loam saprolite
C/B horizon (if it occurs):
C part--same properties as C horizon
B part--same properties as Bt horizon
Some pedons have seams of clayey soil material filling relict rock fractures and old root channels.
Cr horizon:
Bedrock kind--intermediate, mafic crystalline rock, or igneous rock
Bedrock hardness--extremely weakly cemented to moderately cemented
Fracture interval--greater than 10 centimeters (4 inches)
Excavation difficulty--low to high
R horizon:
Bedrock kind--intermediate, mafic crystalline rock, or igneous rock
Bedrock hardness--strongly cemented to indurated
Fracture interval--greater than 10 centimeters (4 inches)
Excavation difficulty--very high or extremely high
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Landscape: Piedmont uplands
Landform: Interstream divides, ridges, and side slopes
Parent Material: Residuum weathered from mafic metamorphic or igneous rock high in ferromagnesian minerals
Slope: 2 to 60 percent
Elevation: 91 to 427 meters (300 to 1,400 feet)
Mean Annual Air Temperature: 52 to 57 degrees
Mean Annual Precipitation: 1017 to 1397 millimeters (40 to 55 inches)
Frost Free Period: 160 to 205 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Halifax soils--have a clayey subsoil and are greater than 152 centimeters (60 inches) to bedrock; on similar landforms
Jackland soils--have a clayey subsoil and have iron depletions in the upper part of the subsoil; on lower-lying landforms
Mirerock soils--have a clayey subsoil and hard bedrock at 102 to 152 centimeters (40 to 60 inches); on similar landforms
Spriggs soils--have a fine-loamy subsoil and soft bedrock at 20 to 40 inches; on similar landforms
Zion soils--have a clayey subsoil and hard bedrock at 51 to 102 centimeters; on similar landforms
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Agricultural Drainage Class: Well drained
Index Surface Runoff: Medium to very high
Saturated Hydraulic Conductivity Class: Moderately high
USE AND VEGETATION:
Major Uses: Hayland and pasture, woodland, and cropland
Dominant Vegetation: Where cultivated--corn, small grain, soybeans, tobacco, and lespedeza. Where wooded--shortleaf pine, Virginia pine, eastern red cedar, blackjack oak, and post oak.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Auburn, Alabama
DISTRIBUTION AND EXTENT:
Distribution: North Carolina and Virginia
Extent: Small
SERIES ESTABLISHED: Surry County, North Carolina; 2003.
REMARKS: Siloam soils were previously mapped as Wilkes soils. The April 1997 relocation of the mesic/thermic line in MLRA 136 in North Carolina and Virginia necessitated the establishment of a mesic counterpart. The June 2026 revision changed the format. No data was changed.
Diagnostic horizons and soil characteristics recognized in this pedon:
Ochric epipedon--the zone from 0 to 25 centimeters (0 to 10 inches) (Ap horizon)
Argillic horizon--the zone from 25 to 38 centimeters (10 to 15 inches) (Bt horizon)
Paralithic contact--the contact at 38 centimeters (15 inches) (Cr horizon)
Paralithic materials--the zone from 38 to 66 centimeters (15 to 26 inches) (Cr horizon)
Other soil features identified with this pedon:
Presence of hard bedrock at 66 centimeters (26 inches) (R horizon)
ADDITIONAL DATA:
Laboratory Data: No laboratory data available.
Database Information:
Typical Pedon Data Mapunit ID--82678
User Pedon ID--Siloam-OSD Surry County, NC
TABULAR SERIES DATA:
Slope Airtemp FrFr/Seas Precip Elevation
2-60 52-57 160-205 40-55 300-1400
FloodL FloodH Watertable Kind Months Bedrock Hardness
NONE >6.0 - - 10-20 SOFT
Depth Texture 3-Inch No-10 Clay% -CEC-
0-8 SL FSL L 0-10 75-100 5-20 4-6
0-8 SCL CL L 0-10 75-100 20-35 4-12
0-8 GR-SL GR-L GR-FSL 5-15 50-75 5-20 4-10
8-15 CL C SCL L 0-10 50-100 10-45 6-18
15-26 WB - - - -
26 UWB - - - -
Depth -pH- O.M. Salin Permeab Shnk-Swll
0-8 5.1-6.5 0.5-2 0.0 2.0-6.0 LOW
0-8 5.1-6.5 0.5-1 0.0 0.6-2.0 MODERATE
0-8 5.1-6.5 0.5-2 0.0 2.0-6.0 LOW
8-15 5.6-7.8 0-0.5 0.0 0.2-0.6 MODERATE
15-26 - - 0.0 0.06-0.2 -
26 - - 0.0 <0.06 -
________________________________________
National Cooperative Soil Survey
U.S.A.