LOCATION FLANAGAN IL+INEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aquic Argiudolls
TYPICAL PEDON: Flanagan silt loam - on a 1 percent convex south-facing slope in a grass border of the University of Illinois experimental plots at an elevation of about 223 meters (730 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
A1--0 to 20 cm (0 to 8 inches); very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; moderate medium granular structure; friable; slightly acid; gradual smooth boundary.
A2--20 to 38 cm (8 to 15 inches); very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate medium granular structure; friable; slightly acid; clear smooth boundary. [Combined thickness of the A horizon is 25 to 46 cm (10 to 18 inches).]
A3--38 to 46 cm (15 to 18 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate medium granular structure; friable; slightly acid; clear smooth boundary. [ 0 to 15 cm (0 to 6 inches) thick]
Bt1--46 to 58 cm (18 to 23 inches); dark grayish brown (10YR 4/2) silty clay loam; moderate fine subangular blocky structure; firm; many distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; few fine faint brown (10YR 4/3) iron-manganese accumulations in the matrix; moderately acid; clear smooth boundary.
Bt2--58 to 81 cm (23 to 32 inches); dark grayish brown (10YR 4/2) silty clay loam; moderate medium subangular blocky structure; firm; many distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; common fine faint brown(10YR 5/3 and 10YR 4/3) iron-manganese accumulations in the matrix; moderately acid; clear smooth boundary.
Bt3--81 to 97 cm (32 to 38 inches); yellowish brown (10YR 5/4) silty clay loam; moderate medium subangular blocky structure; firm; many distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; common fine faint light yellowish brown (10YR 6/4) and distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; slightly acid; clear smooth boundary.
Bt4--97 to 114 cm (38 to 45 inches); 40 percent yellowish brown (10YR 5/6), 30 percent light brownish gray (10YR 6/2), and 30 percent brown (10YR 5/3) silt loam; weak medium subangular blocky structure; friable; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; slightly acid; gradual smooth boundary.[Combined thickness of the Bt horizon is 66 to 102 cm (26 to 40 inches).]
2Bt5--114 to 125 cm (45 to 49 inches); 35 percent yellowish brown (10YR 5/4), 35 percent light olive brown (2.5Y 5/4), and 30 percent light brownish gray (10YR 6/2) silt loam; weak coarse subangular blocky structure; firm; few distinct dark grayish brown (10YR 4/2) clay films on faces of peds; 5 percent fine gravel; neutral; abrupt smooth boundary. [8 to 38 cm (3 to 15 inches) thick]
2C--125 to 152 cm (49 to 60 inches); yellowish brown (10YR 5/4) loam; massive; firm; common medium rounded white (10YR 8/1) weakly cemented calcium carbonate nodules throughout; common fine and medium distinct light brownish gray (10YR 6/2) iron depletions in the matrix; 5 percent fine gravel; slightly effervescent; slightly alkaline.
TYPE LOCATION: Champaign County, Illinois; about 1 mile south of Champaign on University of Illinois south farm; 1,607 feet east and 1,405 feet north of the southwest corner, sec. 19, T. 19 N., R. 9 E.; USGS Urbana topographic quadrangle; lat. 40 degrees, 5 minutes, 14 seconds N., and long. 88 degrees, 13 minutes, 57 seconds W.; NAD 27; UTM Zone 16T, 0394923 easting and 4438169 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon ranges from 114 to 165 cm (45 to 65 inches). The depth to horizons with more than 10 percent sand ranges from 102 to 152 cm (40 to 60 inches). Soil development extends into the glacial till. The depth to carbonates ranges from 114 to 165 cm (45 to 65 inches). The mollic epipedon is 25 to 61 cm (10 to 24 inches) thick and includes the upper part of the B horizon in some pedons. The particle-size control section averages between 35 and 42 percent clay and less than 10 percent fine sand or coarser.
The A and Ap horizons have hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 or 2. They commonly are silt loam but in some pedons it is silty clay loam. Clay content ranges from 20 to 30 percent. Reaction ranges from neutral to strongly acid.
Some pedons have an AB or BA horizon.
The Bt has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 6. It is dominantly silty clay loam, but some subhorizons are silty clay or silt loam. Clay content ranges from 35 to 42 percent. It is neutral to moderately acid.
The 2Bt has hue of 7.5YR, 10YR, or 2.5Y, value of 4 to 6, and chroma of 1 to 6. Redoximorphic features are present. It is loam, clay loam, silt loam, or silty clay loam. Clay content ranges from 20 to 30 percent and sand content ranges from 15 to 40 percent. Individual subhorizons have up to 40 percent clay. Gravel content ranges from 1 to 15 percent. Reaction is slightly acid to slightly alkaline and some pedons contain carbonates in the lower part.
The 2C horizon has hue of 7.5YR, 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 2 to 6. It commonly is loam but includes clay loam, silt loam, or silty clay loam. It is slightly alkaline or moderately alkaline and contains carbonates.
COMPETING SERIES: These are the Biddle, Herrick, Ipava, Macksburg, Malvern, and Timewell, soils. Biddle, Herrick, Ipava, Malvern, and Timewell soils average less than 15 percent sand in the lower part of the series control section. Macksburg soils do not have carbonates within a depth of 165 cm (65 inches).
GEOGRAPHIC SETTING: Flanagan soils are on convex slopes of till plains of Wisconsinan Age. Slopes are typically between 0 and 4 percent but range to 7 percent. The soils formed in 102 to 152 cm (40 to 60 inches) of loess and the underlying calcareous till. Mean annual temperature ranges from 8 to 12 degrees C (46 to 54 degrees F); mean annual precipitation ranges from 737 to 889 mm (29 to 35 inches); frost-free period ranges from 160 to 180 days; and elevation ranges from 207 to 311 meters (680 to 1020 feet) above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Catlin, Dana, Drummer, Milford, Raub, and Saybrook soils. The moderately well drained Catlin soils and the poorly drained Drummer soils are on nearby landscapes and form a drainage sequence. The moderately well drained Dana and Saybrook soils and somewhat poorly drained Raub soils are on nearby parts of the till plain where loess is thinner than 102 cm (40 inches). The poorly drained and very poorly drained Milford soils are lower on the landscape in lacustrine areas.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. An apparent seasonal high water table is at a depth of 31 to 61 cm (1 to 2 feet) at some time between January and May in most years. The potential for surface runoff is low to high. Saturated hydraulic conductivity is moderately high (1.41 to 4.23 micrometers per second). Permeability is moderately slow.
USE AND VEGETATION: Most areas of Flanagan soils are used to grow corn and soybeans. Native vegetation is prairie grasses.
DISTRIBUTION AND EXTENT: Flanagan soils are in central and north-central Illinois and in west-central Indiana. The acreage is of large extent (more than 540,000 acres correlated to date) in MLRAs 95B, 108A, and 110.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: DeWitt County, Illinois, 1937.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - the zone from the surface to 18 inches. (A1, A2, and AB horizons);
argillic horizon - the zone from 18 to 49 inches (Bt1, Bt2, Bt3, Bt4, and 2Bt5 horizons):
aquic conditions - redoximorphic features in horizons below the mollic epipedon; udic moisture regime; mesic temperature regime.
ADDITIONAL DATA: For series typical pedon refer to University of Illinois laboratory samples 17882-17890. Data for 13 additional pedons is in the database of soils sampled by the University of Illinois.