LOCATION WHITCOMB IN
Established Series
Rev. DLM-GRS-BGN
11/2021
WHITCOMB SERIES
The Whitcomb series consists of very deep, somewhat poorly drained soils that formed loess, silty slope alluvium, and the underlying residuum from black shale. They are moderately deep to a layer with fragic soil properties. Whitcomb soils are on strath terraces. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 1092 mm (43 inches), and mean annual temperature is about 12 degrees C (54 degrees F).
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Aeric Paleaquults
TYPICAL PEDON: Whitcomb silt loam, on a 1 percent slope in a pasture field at an elevation of about 174 meters (570 feet) above MSL. (Colors are for moist soil unless otherwise stated.)
A--0 to 5 cm (2 inches); brown (10YR 4/3) silt loam, very pale brown (10YR 7/3) dry; moderate fine granular structure; friable; many very fine and fine roots; moderately acid; abrupt smooth boundary. [0 to 10 cm (4 inches) thick]
Ap--5 to 23 cm (2 to 9 inches); brown (10YR 5/3) silt loam, very pale brown (10YR 7/3) dry; moderate medium granular structure; friable; common very fine and fine roots; common fine faint light yellowish brown (10YR 6/4) masses of oxidized iron in the matrix; common medium irregular iron-manganese concretions; 1 percent gravel; moderately acid; abrupt smooth boundary. [18 to 30 cm (7 to 12 inches) thick]
BE--23 to 38 cm (9 to 15 inches); light yellowish brown (10YR 6/4) silt loam; weak fine subangular blocky structure; friable; common very fine roots; common fine prominent brownish yellow (10YR 6/8) masses of oxidized iron in the matrix; common fine irregular iron-manganese concretions; common medium distinct light gray (10YR 7/2) iron depletions in the matrix; 1 percent gravel; extremely acid; clear wavy boundary. [10 to 20 cm (4 to 8 inches) thick]
Btg1--38 to 56 cm (15 to 22 inches); light brownish gray (10YR 6/2) silty clay loam; weak medium prismatic structure parting to moderate medium subangular blocky; friable; few very fine roots between peds; many distinct light brownish gray (10YR 6/2) clay films on faces of peds; many medium distinct light yellowish brown (10YR 6/4) and common medium prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; few fine irregular iron-manganese concretions; 1 percent gravel; extremely acid; clear wavy boundary.
Btg2--56 to 76 cm (22 to 30 inches); light brownish gray (10YR 6/2) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots between peds; many distinct gray (10YR 6/1) clay films on faces of peds; many medium prominent strong brown (7.5YR 5/8) and common distinct light yellowish brown (10YR 6/4) masses of oxidized iron in the matrix; common medium irregular iron-manganese concretions; 1 percent gravel; extremely acid; gradual wavy boundary. [Combined thickness of the Bt horizon is 30 to 46 cm (12 to 18 inches).]
2Btgx1--76 to 94 cm (30 to 37 inches); gray (10YR 6/1) silty clay loam; moderate coarse prismatic structure parting to moderate coarse subangular blocky; firm; many distinct gray (10YR 6/1) and gray (10YR 5/1) clay films on faces of peds; few prominent very dark gray (N 3/) mangans on faces of peds and in pores; many medium prominent strong brown (7.5YR 5/8) and few distinct light yellowish brown (10YR 6/4) masses of oxidized iron in the matrix; 2 percent gravel; 40 percent brittle; extremely acid; clear wavy boundary.
2Btgx2--94 to 122 cm (37 to 48 inches); gray (10YR 6/1) silty clay loam; weak coarse prismatic structure parting to moderate coarse subangular blocky; firm; common prominent gray (10YR 5/1) clay films on faces of peds; few prominent very dark gray (N 3/) mangans on faces of peds and in pores; many coarse prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; 2 percent gravel; 50 percent brittle; extremely acid; gradual wavy boundary. [Combined thickness of the 2Btgx horizon is 41 to 51 cm (16 to 20 inches).]
3Btg--122 to 142 cm (48 to 56 inches); gray (10YR 6/1) silty clay; weak medium subangular blocky structure; firm; few prominent gray (10YR 5/1) clay films on faces of peds; many coarse prominent strong brown (7.5YR 5/8) masses of oxidized iron in the matrix; 2 percent gravel; extremely acid; clear wavy boundary. [15 to 25 cm (6 to 10 inches) thick]
3BCg--142 to 155 cm (56 to 61 inches); 60 percent light brownish gray (10YR 6/2) and 30 percent pinkish gray (7.5YR 6/2) very parachannery silty clay loam; moderate thick platy structure; firm; many medium distinct brown (7.5YR 4/4) and few fine prominent strong brown (7.5YR 5/8) masses of oxidized iron in the matrix; 40 percent parachanners (shale); extremely acid; abrupt wavy boundary. [10 to 25 cm (4 to 10 inches) thick]
3R--155 to 203 cm (61 to 80 inches); very dark gray (10YR 3/1) very strongly cemented, fissile shale.
TYPE LOCATION: Scott County, Indiana; about 3/4 mile northeast of Austin; 210 feet east and 180 feet south of the center of sec. 30, T. 4 N., R. 7 E.; USGS Crothersville, Indiana topographic quadrangle; lat. 38 degrees 45 minutes 25.974 seconds N. and long. 085 degrees 47 minutes 06.041 seconds W.; UTM Zone 16, 605567.472 easting and 4290535.936 northing, NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the loess: 61 to 102 cm (24 to 40 inches)
Depth to the base of the argillic horizon: 122 to 165 cm (48 to 65 inches)
Depth to a layer with fragic soil properties: 61 to 91 cm (24 to 36 inches)
Depth to bedrock (lithic contact): 152 to 203 cm (60 to 80 inches)
Particle-size control section: averages 24 to 34 percent clay and 4 to 12 percent sand
Rock fragments: in Btg and 2Btgx are dominantly of igneous lithology
Ap horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 3 or 4
Texture: silt loam
Clay content: 12 to 24 percent
Sand content: 4 to 12 percent
Reaction: very strongly acid to neutral
A horizon (0 to 10 cm or 0 to 4 inches thick):
Hue: 10YR
Value: 3 or 4
Chroma: 3 or 4
Texture: silt loam
Clay content: 12 to 24 percent
Sand content: 4 to 12 percent
Reaction: very strongly acid or strongly acid
BE horizon:
Hue: 10YR
Value: 6
Chroma: 3 to 6
Texture: silt loam
Clay content: 20 to 26 percent
Sand content: 4 to 12 percent
Reaction: extremely acid or very strongly acid
Btg horizon:
Hue: 10YR
Value: 6 or 7
Chroma: 1 or 2
Texture: silt loam or silty clay loam
Clay content: 24 to 32 percent
Sand content: 4 to 12 percent
Reaction: extremely acid or very strongly acid
2Btgx horizon:
Hue: 10YR
Value: 5 to 7
Chroma: 1 or 2
Texture: silty clay loam
Clay content: 27 to 35 percent
Sand content: 5 to 12 percent
Rock fragment content: 1 to 3 percent gravel
Percent brittleness: 30 to 60
Reaction: extremely acid or very strongly acid
3Btg horizon:
Hue: 7.5YR or 10YR
Value: 4 to 6
Chroma: 1 or 2
Texture: silty clay loam or silty clay
Clay content: 35 to 50 percent
Sand content: 5 to 10 percent
Rock fragment content: 0 to 3 percent gravel
Reaction: extremely acid or very strongly acid
3BCg or 3CBg horizon:
Hue: 7.5YR or 10YR
Value: 4 to 6
Chroma: 1 or 2
Texture: parachannery to extremely parachannery analogues of silty clay loam or silty clay
Clay content: 35 to 45 percent
Sand content: 5 to 10 percent
Pararock fragment content: 15 to 60 parachanners
Reaction: extremely acid or very strongly acid
COMPETING SERIES: There are no other series in the same family.
GEOGRAPHIC SETTING: Whitcomb soils are on strath terraces adjacent to till plains considered to be of the Illinoian stage. Slope ranges from 0 to 2 percent. They formed in loess, silty slope alluvium, and the underlying residuum from black shale. In Indiana, the shale is from the New Albany formation, Devonian System. Mean annual precipitation ranges from 1016 to 1143 mm (40 to 45 inches). Mean annual temperature ranges from 11 to 14 degrees C (52 to 57 degrees F). Frost-free period is 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Deputy,
Jennings,
Scottsburg and
Trappist soils. The moderately well drained Deputy and Jennings soils are on backslopes of higher lying till plains. The moderately well drained Scottsburg soils are on summits and shoulders of strath terraces. The well drained, moderately deep Trappist soils are on lower lying backslopes.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. In undrained areas, the depth to the top of a perched seasonal high water table ranges from 15 to 46 cm (0.5 to 1.5 feet) between December and April in normal years. In drained areas, the depth to the top of the perched seasonal high water table ranges from 15 to 61 cm (0.5 to 2.0 feet) between December and April in normal years. The potential for surface water runoff is medium. Saturated hydraulic conductivity is moderately high or high above the horizon with fragic soil properties and low to moderately high in and below this horizon. Permeability is moderate above the horizon with fragic soil properties and slow or very slow in and below this horizon.
USE AND VEGETATION: Most areas are being used for growing cultivated crops and hay and pasture. A few areas are used for woodland. Native vegetation is mixed hardwood forest.
DISTRIBUTION AND EXTENT: MLRA 114A in southeastern Indiana. The series is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AMHERST, MASSACHUSETTS
SERIES ESTABLISHED: Scott County, Indiana, 1995.
REMARKS: The Whitcomb series was made inactive in 1972. It is reactivated and the concept updated with this description. The basic concept remains the same as was in 1972.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 23 cm (9 inches) (A and Ap horizons).
Argillic horizon: 38 to 142 cm (15 to 56 inches) (Btg1, Btg2, 2Btgx1, 2Btgx2, 3Btg horizons).
Fragic soil properties: 76 to 122 cm (30 to 48 inches) (2Btgx1 and 2Btgx2 horizons).
Redoximorphic features: at 23 to 155 cm (9 to 61 inches); clay films with a chroma of 2 or less are iron depleted redoximorphic features.
Lithic contact: at 155 cm (61 inches).
ADDITIONAL DATA: Lab data available for the typical pedon, S89IN-143-14 is at the National Soil Survey Lab, Lincoln, NE.
National Cooperative Soil Survey
U.S.A.