LOCATION BIDDLE ILEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aquic Argiudolls
TYPICAL PEDON: Biddle silt loam - nearly level, in a Herrick-Biddle-Piasa complex, in a cultivated field at an elevation of about 145 meters (475 feet) above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 cm (0 to 7 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine granular structure; friable; many very fine roots; few fine faint spherical black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 23 percent clay; slightly acid; abrupt smooth boundary.
A--18 to 33 cm (7 to 13 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine and medium granular structure; friable; many very fine roots; few fine faint spherical black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 22 percent clay; neutral; clear smooth boundary. (Combined thickness of the Ap and A horizons is 25 to 46 centimeters or 10 to 18 inches.)
BE--33 to 41 cm (13 to 16) inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak medium platy structure parting to weak fine granular; friable; common very fine roots; common distinct light gray (10YR 7/2), dry, clay depletions on faces of peds; few fine faint spherical black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 21 percent clay; neutral; clear smooth boundary. (0 to 15 centimeters or 0 to 6 inches thick)
Bt--41 to 64 cm (16 to 25 inches); brown (10YR 4/3) silty clay loam; moderate fine and medium subangular blocky structure; firm; common very fine roots; many distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine faint grayish brown (10YR 5/2) iron depletions and common fine distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common fine distinct irregular black (7.5YR 2.5/1) iron-manganese accumulations with sharp strong brown (7.5YR 5/6) boundaries; about 38 percent clay; neutral; clear smooth boundary.
Btng1--64 to 91 cm (25 to 36 inches); grayish brown (10YR 5/2) silty clay loam; moderate medium subangular blocky structure; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common fine and medium distinct irregular black (7.5YR 2.5/1) iron-manganese accumulations with clear strong brown (7.5YR 4/6) boundaries; about 37 percent clay; slightly alkaline; clear smooth boundary.
Btng2--91 to 117 cm (36 to 46 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium subangular blocky structure; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; many fine and medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common medium and coarse prominent irregular black (7.5YR 2.5/1) iron-manganese accumulations with clear strong brown (7.5YR 4/6) boundaries; about 34 percent clay; slightly alkaline; clear smooth boundary.
Btng3--117 to 140 cm (46 to 55 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium subangular blocky structure; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine and medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common medium and coarse prominent irregular black (7.5YR 2.5/1) iron-manganese accumulations with clear strong brown (7.5YR 4/6) boundaries; about 29 percent clay; slightly alkaline; gradual smooth boundary. (Combined thickness of Bt and Btng horizons is 76 to 122 centimeters or 30 to 48 inches.)
BCtng--140 to 158 cm (55 to 62 inches); grayish brown (2.5Y 5/2) silt loam; weak coarse subangular blocky structure; friable; few distinct dark grayish brown (10YR 4/2) clay films on vertical faces of peds; common fine and medium prominent brownish yellow (10YR 6/6) masses of oxidized iron in the matrix; common medium and coarse prominent irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) iron-manganese accumulations with diffuse strong brown (7.5YR 4/6) boundaries; about 24 percent clay; slightly alkaline; gradual smooth boundary. (0 to 25 centimeters or 0 to 10 inches thick)
Cg1--158 to 193 cm (62 to 76 inches); light brownish gray (2.5Y 6/2) silt loam; massive; friable; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; few fine and medium prominent irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) iron-manganese accumulations with diffuse strong brown (7.5YR 4/6) boundaries; about 22 percent clay; slightly alkaline; clear smooth boundary.
2Cg2--193 to 251 cm (76 to 99 inches); brown (7.5YR 5/2) silt loam; massive; friable; many fine and medium distinct brown (7.5YR 5/4) masses of oxidized iron in the matrix; common fine and medium distinct irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) iron-manganese accumulations with diffuse strong brown (7.5YR 4/6) boundaries; about 25 percent clay, 12 percent sand, and 1 percent pebbles; slightly alkaline.
TYPE LOCATION: St. Clair County, Illinois; about 2 miles southwest of Freeburg; approximately 1,290 feet south and 1,555 feet east of the northwest corner of sec. 1, T. 2 S., R. 8 W.; USGS FREEBURG, ILL. topographic quadrangle; lat. 38 degrees 23 minutes 32 seconds N. and long. 89 degrees 56 minutes 10 seconds W., UTM Zone 16, 243561 easting and 4253423 northing; NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon: 25 to 46 centimeters (10 to 18 inches) and extends into the upper part of the B horizon in some pedons
Depth to the base of the argillic horizon: 102 to 183 centimeters (40 to 72 inches)
Thickness of loess: 152 to 203 centimeters (60 to 80 inches)
Concentration of exchangeable sodium: averaging 5 to 15 percent in the subsoil
Particle-size control section: averages 35 to 42 percent clay and less than 7 percent sand
Other features: Some pedons contain krotovina.
Ap and A horizons:
Hue: 10YR
Value: 2 or 3 (4 or 5 dry)
Chroma: 1 or 2
Texture: silt loam
Clay content: 18 to 27 percent
Reaction: moderately acid to neutral
AE, EA, BA or BE horizon, where present:
Hue: 10YR
Value: 4 or 5
Texture: silt loam
Chroma: 1 to 3
Clay content: 18 to 27 percent
Reaction: moderately acid to neutral
Bt, Btng or BCtng horizon:
Hue: 10YR, 2.5Y, or 5Y
Value: 3 to 5 in the upper part and 4 to 6 in the lower part
Chroma: 1 to 4; most pedons contain redoximorphic features with high or low chroma or both
Texture: silty clay loam or silty clay in the upper part and silty clay loam or silt loam in the lower part
Clay content: 35 to 42 percent in the upper part and 24 to 38 percent in the lower part
Reaction: moderately acid to moderately alkaline and some pedons have carbonates
Cg or 2Cg horizon:
Hue: 7.5YR, 10YR, 2.5Y, 5Y, or is neutral
Value: 5 or 6
Chroma: 0 to 2
Texture: commonly silt loam or, less commonly, silty clay loam, clay loam, or loam
Clay content: 18 to 30 percent
Sand content: 5 to 30 percent
Reaction: neutral to moderately alkaline and some pedons have carbonates
COMPETING SERIES: These are the Flanagan, Herrick, Ipava, Malvern, Rutland, and Timewell series. These soils do not have a concentration of exchangeable sodium in the subsoil.
GEOGRAPHIC SETTING: Biddle soils are on or nearly level parts of broad interfluves on till plains. Slope ranges from 0 to 2 percent. These soils formed in loess, or in loess and the underlying silty pedisediment. Mean annual temperature is 12.2 to 13.9 degrees C (54 to 57 degrees F), mean annual precipitation is 914 to 1016 millimeters (36 to 40 inches), frost-free period is 170 to 200 days, and elevation is 122 to 244 meters (400 to 800 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aviston, Cowden, Fosterburg, Herrick, Oconee, Piasa, and Virden soils. The moderately well drained Aviston soils are on summits, shoulders, and backslopes above the Biddle soils. The poorly drained Cowden, Fosterburg, Piasa, and Virden soils on nearly level or slightly depressional parts of the landform nearby. The Cowden and Virden soils do not have a concentration of exchangeable sodium in the subsoil. The Fosterburg soils have a concentration of exchangeable sodium in the subsoil, and the Piasa soils have a natric horizon. The somewhat poorly drained Herrick and Oconee soils commonly are on similar landform positions. The Herrick soils do not have a concentration of exchangeable sodium in the subsoil. The Oconee soils do not have a concentration of exchangeable sodium in the subsoil, do not have a mollic epipedon, and typically are nearer the drainageways.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Saturated hydraulic conductivity is moderately low or moderately high (0.42 to 1.41 micrometers/sec) in the subsoil and in the substratum formed in loess. Permeability is slow. Surface runoff potential is low. In drained areas, depth to an intermittent perched high water table is 30 to 61 centimeters (1.0 foot to 2.0 feet) from January to May in most years.
USE AND VEGETATION: Most areas are cropped to corn, soybeans, and small grain. Native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT: Southwestern Illinois. Extent is moderate, and mainly in MLRA(s) 108B and 114B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: St. Clair County, Illinois, 1997. The Biddle series was named for the town of Biddleborn in Washington County.
REMARKS: Biddle soils were formerly included with the Herrick-Piasa complex.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to a depth of 33 centimeters or 13 inches (Ap and A horizons).
Argillic horizon - the zone from approximately 41 to 140 centimeters or 16 to 55 inches (Bt, Btng1, Btng2, and Btng3 horizons).
Concentration of exchangeable sodium - the zone from approximately 64 to 158 centimeters or 25 to 62 inches (Btng1, Btng2, Btng3, and BCtng horizons).
Udic moisture regime.
ADDITIONAL DATA: For lab analysis refer to NSSL pedon from St. Clair County - S90-163-009, samples: 91P-991-999.