LOCATION CHENOA ILEstablished Series
TAXONOMIC CLASS: Fine, illitic, mesic Aquic Argiudolls
TYPICAL PEDON: Chenoa silty clay loam - on a nearly level slope in a cultivated field at an elevation of 940 mm 211 meters (691 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 30 cm (0 to 12 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate fine granular structure; friable; few fine roots; neutral; abrupt smooth boundary. [25 to 38 cm (10 to 15 inches) thick]
BA--30 to 41 cm (12 to 16 inches); brown (10YR 4/3) silty clay loam; weak fine prismatic structure parting to moderate fine angular blocky; friable; few very fine roots; many distinct black (10YR 2/1) organic coatings on faces of peds; few fine faint dark grayish brown (10YR 4/2) iron depletions in the matrix; neutral; clear smooth boundary. [0 to 15 cm (0 to 6 inches) thick]
Bt--41 to 53 cm (16 to 21 inches); brown (10YR 4/3) silty clay loam; moderate fine prismatic structure parting to moderate fine angular blocky; friable; few very fine roots; few distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few fine distinct gray (10YR 5/1) iron depletions in the matrix; neutral; clear smooth boundary.
Btg1--53 to 66 cm (21 to 26 inches); grayish brown (10YR 5/2) silty clay loam; moderate fine prismatic structure parting to moderate fine angular blocky; friable; few very fine roots; many distinct dark grayish brown (10YR 4/2) clay films on vertical faces of peds; common medium black (10YR 2/1) very weakly cemented iron-manganese concretions throughout; common medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common fine faint gray (10YR 5/1) iron depletions in the matrix; neutral; clear smooth boundary.
Btg2--66 to 81 cm (26 to 32 inches); grayish brown (10YR 5/2) silty clay loam; moderate medium prismatic structure parting to moderate medium angular blocky; friable; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on vertical faces of peds; common medium black (10YR 2/1) very weakly cemented iron-manganese concretions throughout; common medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common medium faint gray (10YR 5/1) iron depletions in the matrix; neutral; clear smooth boundary. [Combined thickness of the Bt horizon is 23 to 58 cm (9 to 23 inches).]
2Bt--81 to 91 cm (32 to 36 inches); light olive brown (2.5Y 5/4) silty clay loam; weak medium prismatic structure parting to weak medium angular blocky; firm; few very fine roots; few distinct grayish brown (2.5Y 5/2) clay films on faces of peds; common medium distinct gray (2.5Y 6/1) iron depletions in the matrix; 3 percent gravel; slightly alkaline; clear smooth boundary. [10 to 30 cm (4 to 12 inches) thick]
2C--91 to 152 cm (36 to 60 inches); light olive brown (2.5Y 5/4) silty clay loam; massive; firm; few prominent light brownish gray (10YR 6/2) coatings on vertical cleavage planes; common medium distinct gray (2.5Y 6/1) iron depletions in the matrix; 3 percent gravel; strongly effervescent; moderately alkaline.
TYPE LOCATION: Livingston County, Illinois; about 2.5 miles (4 kilometers) southeast of Flanagan; 865 feet (263 meters) west and 105 feet (32 meters) south of the northeast corner of sec. 2, T. 27 N., R. 3 E.; USGS Flanagan South topographic quadrangle; lat. 40 degrees 50 minutes 31 seconds N. and long. 88 degrees 50 minutes 13 seconds W., NAD 27; UTM Zone 16, 345124 easting and 4522838 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon and the depth to carbonates range from 64 to 114 cm (25 to 45 inches). The depth to horizons containing gravel and averaging more than 8 percent sand ranges from 51 to 102 cm (20 to 40 inches). The particle-size control section averages between 35 and 42 percent clay. The upper one-half of the series control section has average sand content of 2 to 8 percent. Reaction is moderately acid to neutral.
The Ap or A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It is silty clay loam or silt loam.
Some pedons have an AB horizon instead of a BA horizon.
The Bt horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 6. It is commonly silty clay loam, but some subhorizons are silty clay. Clay content ranges from 35 to 45 percent.
The lower one-half of the series control section averages 30 to 40 percent clay, but individual subhorizons have as little as 24 percent clay. Average sand content ranges from 5 to 20 percent; sand fraction is poorly sorted (well graded). Average rock fragment content ranges from 1 to 10 percent.
The 2Bt or 2BC horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 to 6. It is commonly silty clay loam or silt loam, but some pedons have thin layers of loam or clay loam. Reaction ranges from slightly acid to slightly alkaline in the 2Bt horizon and neutral to moderately alkaline in the 2BC horizon.
The 2C horizon has hue of 10YR, 2.5Y or 5Y; value of 4 to 6; and chroma of 1 to 6. It is silty clay loam or silt loam with more than 24 percent clay. Reaction is slightly alkaline or moderately alkaline and contains carbonates.
COMPETING SERIES: These are the Clarence, Elliott, Martinton and Strole series. Clarence and Strole soils average more than 42 percent clay in the particle-size control section. Elliott soils have horizons containing gravel and more than 8 percent sand within a depth of 20 inches (51 cm). Martinton soils have in the lower part of the series control section subhorizons with more than 20 percent well sorted (poorly graded) sand.
GEOGRAPHIC SETTING: Chenoa soils are on relatively undissected parts of till plains of Wisconsinan Age. Slope gradients range from 0 to 5 percent. The soils formed in 51 to 102 cm (20 to 40 inches) of loess or other silty material and in the underlying calcareous till. Mean annual temperature ranges from 9 to 11 degrees C (48 to 52 degrees F), mean annual precipitation ranges from 740 to 890 mm (29 to 35 inches), frost-free period ranges from 160 to 180 days, and elevation ranges from 183 to 259 meters (600 to 850 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Andres, Ashkum, Graymont, Symerton, and Varna soils. Andres soils and the moderately well drained Symerton soils formed in loamy outwash and in the underlying till. The Symerton soils are on higher parts of the landform. The poorly drained Ashkum soils are on adjacent lower lying parts of the landform. The moderately well drained Graymont and Varna soils are on adjacent landform positions and on higher areas. Graymont soils are fine-silty. Varna soils formed in less than 20 inches (51 cm) of loess and in the underlying till.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. A perched seasonal high water table is at a depth of 1 to 2 feet below the surface at some time between January and May in most years. The potential for surface runoff is low or medium. Permeability is moderate in the loess or other silty material and slow in the till. Saturated hydraulic conductivity is moderately high to high (4.23 to 14.11 micrometers per second) in the loess or other silty material, and moderately low to moderately high (0.42 to 1.41 micrometers per second) in the till.
USE AND VEGETATION: Most areas are cultivated. Corn, soybeans, oats, and meadow are the principal crops. Native vegetation is prairie grass.
DISTRIBUTION AND EXTENT: North-central and east-central Illinois. Extent is moderate in MLRAs 108A and 110.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Livingston County, Illinois, 1990.
REMARKS: Chenoa is the name of a town in northeastern McLean County, Illinois. Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from 0 to 12 inches (0 to 30 cm) (Ap horizon); argillic horizon - the zone from 16 to 36 inches (41 to 91 cm) (Bt, Btg1, Btg2, and 2Bt horizons).