LOCATION BIDDLE             IL

BIDDLE SERIES

The Biddle series consists of very deep, somewhat poorly drained, slowly permeable soils formed in loess, or in loess and the underlying silty pedisediment on nearly level parts of broad interfluves on till plains. Slope ranges from 0 to 2 percent. Mean annual temperature is about 55 degrees F., and mean annual precipitation is about 38 inches.

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 475 feet above sea level. (Colors are for moist soil unless otherwise stated.)

Ap--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 rounded 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--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 rounded 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 10 to 18 inches.)

Eg--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 rounded 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 6 inches thick)

Bt--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 iron accumulation in the matrix; common fine irregular black (7.5YR 2.5/1) and strong brown (7.5YR 5/6) masses of iron-manganese accumulation with sharp boundaries; about 38 percent clay; neutral; clear smooth boundary.

Btng1--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 iron accumulation in the matrix; common fine and medium irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation with clear strong brown (7.5YR 4/6) boundaries; about 37 percent clay; slightly alkaline; clear smooth boundary.

Btng2--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 iron accumulation in the matrix; common medium and coarse irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation with clear strong brown (7.5YR 4/6) boundaries; about 34 percent clay; slightly alkaline; clear smooth boundary.

Btng3--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 iron accumulation in the matrix; common medium and coarse irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation with clear strong brown (7.5YR 4/6) boundaries; about 29 percent clay; slightly alkaline; gradual smooth boundary. (Combined thickness of Bt horizon ranges from 30 to 48 inches.)

BCtng--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 iron accumulation in the matrix; common medium and coarse irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) masses of iron-manganese accumulation with diffuse strong brown (7.5YR 4/6) boundaries; about 24 percent clay; slightly alkaline; gradual smooth boundary. (0 to 10 inches thick)

Cg1--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 iron accumulation in the matrix; few fine and medium irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) masses of iron-manganese accumulation with diffuse strong brown (7.5YR 4/6) boundaries; about 22 percent clay; slightly alkaline; clear smooth boundary.

2Cg2--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 iron accumulation in the matrix; common fine and medium irregular black (7.5YR 2.5/1) and dark brown (7.5YR 3/3) masses of iron-manganese accumulation 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. NAD 27.

RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon is 40 to 72 inches. Loess thickness ranges from 60 to 80 inches. The mollic epipedon is 10 to 18 inches in thickness and extends into the upper part of the B horizon in some pedons. A concentration of exchangeable sodium, averaging between 5 and 15 percent, occurs in the subsoil. Carbonates, where present, typically occur in the B horizon, but they occur in the BCg and Cg horizons in some pedons. The particle-size control section averages 35 to 42 percent clay. Sand content is less than 7 percent in the particle-size control section. Some pedons contain krotovina.

The Ap and A horizons have hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 to 2. Clay content is 18 to 27 percent. Reaction is moderately acid to neutral.

The E horizon, where present, has hue of 10YR, value of 4 or 5, and chroma of 1 to 2. Clay content is 18 to 27 percent. Reaction is moderately acid to neutral.

The Bt or Btng horizon has hue of 10YR, 2.5Y, or 5Y; value of 3 to 5 in the upper part and 4 to 6 in the lower part; and chroma of 1 to 4. Most pedons contain redoximorphic features with high or low chroma or both. Clay content is 35 to 42 percent in the upper part and 24 to 38 percent in the lower part. Reaction is moderately acid to moderately alkaline.

The Cg or 2Cg horizon has hue of 7.5YR, 10YR, 2.5Y, 5Y, or is neutral; value of 5 or 6; and chroma of 0 to 2. Texture is commonly silt loam or, less commonly, silty clay loam, clay loam, or loam. Clay content is 18 to 30 percent and sand content is 5 to 30 percent. Reaction is neutral to moderately alkaline.

COMPETING SERIES: These are the Flanagan, Herrick, Ipava, Macksburg, 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 54 to 57 degrees F., mean annual precipitation is 36 to 40 inches, frost-free period is 170 to 200 days, and elevation is 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 PERMEABILITY: Somewhat poorly drained. Permeability is slow. 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. Surface runoff potential is low. In drained areas, depth to an intermittent perched high water table is 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 114.

MLRA OFFICE 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 13 inches (Ap and A horizons).
Argillic horizon - the zone from approximately 16 to 55 inches (Bt, Btng1, Btng2, and Btng3 horizons).
Concentration of exchangeable sodium - the zone from approximately 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.