LOCATION IREDELL SC+AL GA NC VA
Established Series
Rev. RLV/ECH/DTA
12/2019
IREDELL SERIES
The Iredell series consists of moderately well drained, very slowly permeable soils. These soils formed in material weathered from diabase, diorite, gabbro, and other rocks high in ferro-magnesium minerals. They are on uplands throughout the Piedmont. Slope is dominantly less than 6 percent but ranges up to 15 percent.
TAXONOMIC CLASS: Fine, mixed, active, thermic Oxyaquic Vertic Hapludalfs
TYPICAL PEDON: Iredell sandy loam--pasture. (Colors are for moist soil unless otherwise stated.)
Ap1--0 to 5 inches; dark grayish brown (2.5Y 4/2) sandy loam; weak medium granular structure; friable, slightly sticky, slightly plastic; many fine and medium roots; 1 percent fine pebbles; few fine black concretions; slightly acid; clear smooth boundary. (4 to 7 inches thick)
Ap2--5 to 7 inches; dark grayish brown (10YR 4/2) loam; moderate medium granular structure; friable, slightly sticky, slightly plastic; many fine and medium roots; few fine black concretions; neutral; clear wavy boundary. (0 to 3 inches thick)
Btss1--7 to 11 inches; brown (10YR 4/3) clay; moderate medium angular blocky structure; very firm, very sticky, very plastic; many fine and medium roots; common distinct clay films on faces of peds; common slickensides; many fine (1 to 2 mm) black concretions; slightly acid; gradual smooth boundary.
Btss2--11 to 20 inches; brown (10YR 4/3) clay; moderate medium and coarse angular blocky structure; very firm, very sticky, very plastic; many fine and medium roots along faces of peds; common distinct clay films on faces of peds; common slickensides and pressure faces; common fine black concretions; few fine weathered feldspar crystals; neutral; gradual smooth boundary.
Btg--20 to 24 inches; dark grayish brown (2.5Y 4/2) clay; moderate medium and coarse angular blocky structure; very firm, very sticky, very plastic; many fine and medium roots, mostly along faces of peds; few fine pores; common distinct clay films on faces of peds; few medium black concretions; few fine weathered feldspar crystals; slightly acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 13 to 30 inches)
BC--24 to 27 inches; olive (5Y 4/3) loam; common medium distinct very pale brown (10YR 7/3) and few fine distinct dark grayish brown (2.5Y 4/2) and black (N 2/0) mottles; moderate medium and coarse angular blocky structure; firm, sticky, plastic; many fine and medium roots along faces of peds; few medium pores; common distinct clay films on faces of peds; common soft dark grayish brown and black saprolite; neutral; clear wavy boundary. (0 to 8 inches thick)
C1--27 to 32 inches; finely mottled dark greenish gray, very pale brown, and yellowish brown loam; 80 percent saprolite that crushes easily; many fine roots and few distinct clay films along cleavage planes; neutral; gradual wavy boundary.
C2--32 to 44 inches; finely mottled dark greenish gray, very pale brown, black and yellowish brown sandy loam; 90 percent saprolite that crushes easily; many fine roots and few distinct clay films along cleavage planes; moderately alkaline; gradual wavy boundary.
C3--44 to 62 inches; finely mottled dark greenish gray, yellowish brown, black and very pale brown sandy loam; 90 percent saprolite that crushes easily; few fine roots along cleavage planes; 10 percent fragments of hard rock; moderately alkaline.
TYPE LOCATION: Chester County, South Carolina; on U.S. Highway 72 bypass one mile south of Chester; site is across road from Southside School, 233 feet north of fire hydrant.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 20 to 40 inches. Depth to paralithic contact (Cr horizon) is 40 to more than 60 inches. Depth to hard bedrock is more than 60 inches. Linear extensibility totals 6.0 cm or more between the surface and paralithic contact. Most pedons have few to many dark concretions throughout the profile. Many pedons have few to many dark mottles or soft bodies in the B and C horizons. Some pedons have few to many flakes of mica or crystals of feldspar in the B and C horizons. The soil is strongly acid to neutral in the A horizon, moderately acid to mildly alkaline in the B horizon, and neutral to moderately alkaline in the C horizon. Content of rock fragments, up to 24 inches in diameter, ranges from 0 to 30 percent in the A horizon and E horizon, 0 to 20 percent in the Bt horizon, and 0 to 10 percent in the C horizon.
The A or Ap horizon has hue of 10YR to 5Y, value of 4 or 5, and chroma of 2 to 4. It is sandy loam, fine sandy loam, loam, silt loam, or clay loam in the fine-earth fraction.
A thin or discontinuous E horizon, where present, has hue of 10YR or 2.5Y, value of 6 or 7, and chroma of 1 to 3. It is sandy loam, fine sandy loam, loam, silt loam, or clay loam in the fine-earth fraction.
The upper part of the Bt or Btss horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 3 to 6. The middle part of the Bt or Btss horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 3 to 6. The lower part of the Bt ot Btss horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 2 to 6. Content of clay in the Bt or Btss horizon ranges from 40 to 85 percent in the upper part and from 35 to 60 percent in the middle and lower part. The weighted average content of clay of the upper 20 inches of the Bt or Btss horizon ranges from 40 to 60 percent.
The BC horizon has hue of 10YR to 5Y, value of 4 to 6 and chroma of 3 to 6. Mottles may occur in shades of red brown, or yellow. Texture is clay loam, loam, or sandy clay loam.
The C horizon commonly is mottled or multicolored in shades of white, gray, brown, yellow, or black. It commonly is sandy loam, sandy clay loam, loam, or silt loam with as much as 90 percent soft pararock fragments.
The Cr horizon, where present, is highly fractured, highly weathered rock.
COMPETING SERIES: These are the
Polkton and
White Store series. Polkton soils have a depth to a seasonal high water table of 1.5 to 2.5 feet, a paralithic contact at a depth of 20 to 40 inches and formed from Triassic siltstone, mudstone, shale, and conglomerates. White Store soils have a depth to seasonal high water table of 1.0 to 1.5 feet and are formed from Triassic siltstone, musdtone, sandstone, shale, and conglomerate. Similar soils in other families are the
Brewback,
Crawfordville,
Enon,
Frogsboro,
Pittsboro,
Virgilina,
Winnsboro, and
Wynott series. Brewback soils have iron depletions in the upper part of the argillic and a paralithic contact at a depth of 20 to 40 inches. Crawfordville soils have a paralithic contact at a depth of 20 to 40 inches. Enon and Winnsboro soils do not have slickensides and have a depth to a seasonal high water table at greater than 6 feet. Frogsboro soils is somewhat poorly drained and has smectitic mineralogy. Pittsboro and Wynott soils have a depth to paralithic contact of 20 to 40 inches. Virgilina soils have smectitic mineralogy and a depth to lithic contact of 20 to 40 inches.
GEOGRAPHIC SETTING: Iredell soils are on uplands throughout the Piedmont. Slopes range from 0 to about 15 percent, but generally are less than 6 percent. The soils formed in materials weathered from diabase, diorite, gabbro, and other rocks high in ferro-magnesium mineral. The average annual rainfall ranges from 37 to 60 inches, the frost-free season ranges from 190 to 225 days, and mean annual temperature ranges from 59 to 66 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar
Brewback,
Crawfordville,
Enon,
Frogsboro,
Pittsboro,
Winnsboro, and
Wynott series and the
Cullen,
Davidson,
Helena,
Lloyd,
Mecklenburg, and
Wilkes series. Cullen and Mecklenburg soils have a Bt horizon with a hue of 5YR or redder. Davidson and Lloyd soils are rhodic. Helena soils do not have slickenslides and are strongly to very strongly acid throughout. Wilkes soils are shallow to paralithic contact.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium runoff; very slow permeability.
USE AND VEGETATION: Most areas are used for growing cotton, small grain, hay, or pasture. Forested areas are dominantly in post and white oaks.
DISTRIBUTION AND EXTENT: The Piedmont areas of Alabama, Georgia, North Carolina, South Carolina, and Virginia. The series is of large extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Statesville Area, Iredell County, North Carolina; 1901.
REMARKS: Prior to 1998, Bt horizons having vertic characteristics that were less than 20 inches thick were too thin to place these soils in Vertic Hapludalfs. The eighth edition of the Keys to Soil Taxonomy, 1998 changed the requirements for Vertic subgroups and now these soils fit.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 7 inches (Ap1 and Ap2 horizons)
Argillic horizon - the zone from 7 to 24 inches (Btss1, Btss2, and Bt horizons)
MLRA = 136
ADDITIONAL DATA:
TABULAR SERIES DATA:
SOI-5 Soil Name Slope Airtemp FrFr/Seas Precip Elevation
SC0016 IREDELL 0-15 59- 66 190-225 37-60 300-550
SC0146 IREDELL 0-15 59- 66 190-225 37-60 300-550
SOI-5 FloodL FloodH Watertable Kind Months Bedrock Hardness
SC0016 NONE 1.0-2.0 PERCHED DEC-APR >60
SC0146 NONE 1.0-2.0 PERCHED DEC-APR 40-60 SOFT
SOI-5 Depth Texture 3-Inch No-10 Clay% -CEC-
SC0016 0- 7 GR-L ST-L 1-5 65- 80 10-25 9-13
SC0016 0- 7 FSL SL 0-1 80- 96 10-20 8-12
SC0016 0- 7 L SIL CL 0-1 95-100 15-35 9-15
SC0016 7-24 C 0-0 60-100 40-60 26-30
SC0016 24-27 L SCL CL 0-1 85-100 15-35 15-30
SC0016 27-62 VAR - - - -
SC0146 0- 7 GR-L ST-L 1-5 65- 80 10-25 9-13
SC0146 0- 7 FSL SL 0-1 80- 96 10-20 8-12
SC0146 0- 7 L SIL CL 0-1 95-100 15-35 9-15
SC0146 7-27 C 0-0 60-100 40-60 26-30
SC0146 27-44 L SCL SL 0-1 85-100 10-35 10-25
SC0146 44-62 WB - - - -
SOI-5 Depth -pH- O.M. Salin Permeab Shnk-Swll
SC0016 0- 7 5.1- 7.3 .5-2. 0- 0 2.0-6.0 LOW
SC0016 0- 7 5.1- 7.3 .5-2. 0- 0 2.0-6.0 LOW
SC0016 0- 7 5.1- 7.3 .5-2. 0- 0 0.6-2.0 LOW
SC0016 7-24 5.6- 7.3 0.-.5 0- 0 0.0015-0.06 VERY HIGH
SC0016 24-27 6.1- 7.8 0.-.5 0- 0 0.06-0.2 HIGH
SC0016 27-62 - - - -
SC0146 0- 7 5.1- 7.3 .5-2. 0- 0 2.0-6.0 LOW
SC0146 0- 7 5.1- 7.3 .5-2. 0- 0 2.0-6.0 LOW
SC0146 0- 7 5.1- 7.3 .5-2. 0- 0 0.6-2.0 LOW
SC0146 7-27 5.6- 7.3 0.-.5 0- 0 0.0015-0.06 VERY HIGH
SC0146 27-44 6.1- 7.8 0.-.5 0- 0 0.06-0.2 MODERATE
SC0146 44-62 - - - -
National Cooperative Soil Survey
U.S.A.