LOCATION RANTOUL ILEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Cumulic Vertic Endoaquolls
TYPICAL PEDON: Rantoul silty clay - in a cultivated field at an elevation of 199 meters (653 feet) above mean sea level. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 20 cm (0 to 8 inches); black (N 2.5/) silty clay, dark gray (10YR 4/1) dry; moderate fine granular structure; firm; few very fine roots; neutral; abrupt smooth boundary.
A--20 to 43 cm (8 to 17 inches); black (N 2.5/) silty clay, dark gray (10YR 4/1) dry; moderate medium granular structure; firm; few very fine roots; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; neutral; clear smooth boundary. [Combined thickness of the A horizon is 38 to 71 cm (15 to 28 inches).]
Bg1--43 to 66 cm (17 to 26 inches); very dark gray (10YR 3/1) silty clay, gray (10YR 5/1) dry; strong medium prismatic structure parting to strong fine and medium subangular blocky; firm; few very fine roots; many distinct black (N 2.5/) organic coatings on faces of peds; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; few coarse prominent olive (5Y 4/3) iron-manganese accumulations and common fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; 2 percent gravel; neutral; clear smooth boundary.
Bg2--66 to 79 cm (26 to 31 inches); dark gray (5Y 4/1) silty clay; strong medium prismatic structure parting to strong medium subangular blocky; firm; few very fine roots; many distinct very dark gray (5Y 3/1) organic coatings on faces of peds; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; common fine and medium prominent light olive brown (2.5Y 5/6) and yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; 2 percent gravel; neutral; clear smooth boundary.
Bg3--79 to 102 cm (31 to 40 inches); gray (5Y 5/1) silty clay; strong medium prismatic structure parting to strong medium angular blocky; firm; few very fine roots; common distinct discontinuous dark gray (5Y 4/1) slickensides on faces of peds; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; few fine prominent light olive brown (2.5Y 5/6) masses of oxidized iron in the matrix; 2 percent gravel; neutral; clear smooth boundary.
Bg4--102 to 119 cm (40 to 47 inches); variegated dark gray (5Y 4/1) and gray (5Y 5/1) silty clay; moderate medium and coarse prismatic structure parting to moderate medium and coarse angular blocky; firm; few very fine roots; common faint discontinuous dark gray (5Y 4/1) slickensides on faces of peds; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; common fine prominent yellowish brown (10YR 5/6 and 5/8) masses of oxidized iron in the matrix; 3 percent gravel; slightly alkaline; abrupt smooth boundary. [Combined thickness of the Bg horizon is 51 to 86 cm (20 to 35 inches).]
BCg--119 to 152 cm (47 to 60 inches); variegated gray (5Y 5/1) and yellowish brown (10YR 5/6) silty clay; weak coarse prismatic structure parting to weak coarse angular blocky; very firm; common faint dark gray (5Y 4/1) slickensides on vertical faces of peds; few fine very dark brown (7.5YR 2.5/2) very weakly cemented iron-manganese nodules throughout; 3 percent gravel; strongly effervescent; moderately alkaline. [15 to 51 cm (6 to 20 inches) thick]
TYPE LOCATION: Livingston County, Illinois; about 6.4 kilometers (4 miles) southwest of Dwight; 34 meters (111 feet) south and 491 meters (1,612 feet) east of the northwest corner of sec. 29, T. 30 N., R. 7 E.; USGS Dwight, Illinois, topographic quadrangle; lat. 41 degrees 02 minutes 59 seconds N. and long. 88 degrees 27 minutes 04 seconds W., NAD 27; UTM zone 16, 378046 easting and 4545293 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of soil development ranges from 91 to 178 cm (36 to 70 inches). Depth to carbonates ranges from 86 to 152 cm (34 to 60 inches). The mollic epipedon extends to a depth of 61 to 91 cm (24 to 36 inches) and commonly includes the upper part of the Bg horizon. The upper 51 cm (20 inches) or more has a COLE value greater than 0.09. The particle-size control section averages between 45 to 60 percent clay.
The Ap or A horizon has hue of 10YR or is neutral, value of 2 to 3, and chroma of 0 or 1. The texture is silty clay loam or silty clay. Reaction is slightly acid or neutral.
The Bg horizon has hue of 5Y, 2.5Y, or is neutral, value of 2 to 5, and chroma of 0 or 1 and ranging to chroma of 2 in the lower part. Redoximorphic features with higher chroma are commonly present. Texture is silty clay or clay. Reaction is slightly acid or neutral in the upper part and ranges from neutral to moderately alkaline in the lower part.
The BCg horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 6. Texture is silty clay loam, silty clay, or clay, and in some pedons is stratified with thin layers of silt loam below 102 cm (40 inches). Reaction ranges from neutral to moderately alkaline.
The Cg horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 8. Texture is silty clay loam, silty clay, or clay, and is stratified in some pedons. Reaction is slightly alkaline or moderately alkaline. The Cg horizon contains carbonates.
COMPETING SERIES: These are the Chehalem, Clamo, Derrynane, Okoboji, Peotone, Shiloh, Southbrook, Wabash, Zoe and Zook. Chehalem soils are more acid in the lower part of the series control section. Clamo soils have carbonates within a depth of 76 cm (30 inches). Derrynane, Okoboji, Peotone, and Shiloh soils average less than 45 percent clay in the particle-size control section. Southbrook soils average more than 50 percent sand in the lower part of the series control section. Wabash and Zook soils have mollic epipedons that are more than 76 cm (36 inches) thick. Zoe soils have a sodium adsorption ratio of 4 to 10 within a depth of 30 cm (12 inches) and have carbonates within a depth of 61 cm (24 inches).
GEOGRAPHIC SETTING: Rantoul soils are in depressions in nearly level to rolling till plains and glacial lake plains of Wisconsinan Age. These soils formed in sediments from surrounding slopes and till or lakebed sediments. Mineralogy is thought to be smectitic although surrounding sloping areas are formed partly in material high in illite. Summers are hot and winters are cold. Mean annual air temperature ranges from 9 to 11 degrees C (48 to 52 degrees F), mean annual precipitation ranges from 890 to 1020 mm (35 to 40 inches), frost-free period ranges from 140 to 180 days, and elevation ranges from 165 to 290 meters (540 to 950 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: The poorly drained Bryce and Rowe soils are associated on the nearly level areas. They have thinner mollic epipedons. The somewhat poorly drained Clarence and Swygert soils are on more sloping areas.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Where drained, the depth to an apparent seasonal high water table is 15 cm (0.5 foot) above the surface to 30 cm (1.0 foot) below the surface at some time between January and June in most years. The potential for surface runoff is negligible. Saturated hydraulic conductivity is moderately low (0.14 to 0.42 micrometers per second). Permeability is very slow.
USE AND VEGETATION: Drained areas are cultivated. Corn, soybeans, and meadow are the principal crops. Undrained areas are idle or used for pasture. Native vegetation is marsh grasses and sedges.
DISTRIBUTION AND EXTENT: Northeastern Illinois. Extent is moderate in MLRA 110.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Livingston County, Illinois, 1938.
REMARKS: The mineralogy is questioned as to being mixed since the analysis of Rantoul shows it to be marginally smectitic, but the materials from which associated, better drained soils formed are illitic in mineralogy.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon 0 to 66 cm (0 to 26 inches) (Ap, A, and Bg1 horizons); cambic horizon 43 to 152 cm (17 to 60 inches) (Bg1, Bg2, Bg3, Bg4, and BCg horizons).