LOCATION CLARE ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Oxyaquic Argiudolls
TYPICAL PEDON: Clare silt loam - on a north-facing convex slope of 1 percent in a cultivated field at an elevation of 229 meters (750 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 13 cm (0 to 5 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; friable; common very fine roots; neutral; clear smooth boundary.
A--13 to 28 cm (5 to 11 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine and medium subangular blocky structure; friable; common very fine roots; neutral; clear smooth boundary. [Combined thickness for the A horizon ranges from 25 to 51 cm (10 to 20 inches).]
BA--28 to 36 cm (11 to 14 inches); 60 percent dark yellowish brown (10YR 4/4) and 40 percent very dark grayish brown (10YR 3/2) silty clay loam; moderate medium subangular blocky structure; friable; common very fine roots; neutral; gradual wavy boundary.[0 to 20 cm (0 to 8 inches) thick.]
Bt1--36 to 53 cm (14 to 21 inches); dark yellowish brown (10YR 4/4) silty clay loam; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; common fine roots; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds and on surfaces along pores: common distinct brown (10YR 4/3) clay films on faces of peds; neutral; gradual wavy boundary.
Bt2--53 to 71 cm (21 to 28 inches); dark yellowish brown (10YR 4/4) silty clay loam; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; firm; common fine roots; common distinct brown (10YR 4/3) clay films on faces of peds and on surfaces along pores; slightly acid; gradual wavy boundary.
Bt3--71 to 81 cm (28 to 32 inches); dark yellowish brown (10YR 4/4) silt loam; moderate medium and coarse subangular blocky structure; friable; few very fine roots; common distinct brown (10YR 4/3) clay films on faces of peds and on surfaces along pores; common fine distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common medium distinct grayish brown (2.5Y 5/2) iron depletions in the matrix; slightly acid; gradual wavy boundary. [Combined thickness of the Bt horizon ranges from 38 to 76 cm (15 to 30 inches).]
2Bt4--81 to 94 cm (32 to 37 inches); dark yellowish brown (10YR 4/4) loam; moderate medium and coarse subangular blocky structure; friable; few very fine roots; few distinct brown (10YR 4/3) clay films on faces of peds and on surfaces along pores; common medium distinct strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; common medium distinct grayish brown (2.5Y 5/2) iron depletions in the matrix; neutral; clear wavy boundary.
2Bt5--94 to 114 cm (37 to 45 inches); brown (7.5YR 4/4) sandy loam; weak medium and coarse angular blocky structure; friable; few very fine roots; few distinct brown (10YR 4/3) clay films on faces of peds; common medium distinct strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; common medium distinct dark grayish brown (10YR 4/2) iron depletions in the matrix; 2 percent gravel; neutral; gradual wavy boundary.
2Bt6--114 to 155 cm (45 to 61 inches); brown (7.5YR 4/4) clay loam; weak medium and coarse angular blocky structure; friable; few distinct dark brown (7.5YR 3/2) organo-clay films on faces of peds; few distinct brown (10YR 4/3) clay films on faces of peds; common medium rounded black (10YR 2/1) very weakly cemented iron-manganese concretions throughout; common medium rounded yellowish brown (10YR 5/6) very weakly cemented iron-manganese concretions throughout; 5 percent gravel; neutral; clear smooth boundary. [Combined thickness of the 2Bt horizon ranges from 15 to 76 cm (6 to 30 inches).]
2C--155 to 203 cm (61 to 80 inches); brown (7.5YR 5/4) stratified gravelly sandy loam and loam; massive; friable; 17 percent gravel; strongly effervescent; moderately alkaline.
TYPE LOCATION: DeKalb County, Illinois; about 2.4 kilometers (1.5 miles) north of Fairdale; 366 meters (1,200 feet) north and 670 meters (2,200 feet) east of the southwest corner of sec. 7, T. 42 N., R. 3 E.; USGS Cherry Valley topographic quadrangle; lat. 42 degrees 07 minutes 32 seconds N. and long. 88 degrees 55 minutes 51 seconds W., NAD 27; UTM Zone 16T, 340388 easting, 4665526 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of soil development ranges from 102 to 178 cm (40 to 70 inches). Depth to carbonates is greater than 102 cm (40 inches). The depth to horizons with greater than 15 percent fine and medium sand ranges from 51 to 102 cm (20 to 40 inches). The particle-size control section averages between 25 and 35 percent clay and less than 10 percent fine sand or coarser.
The Ap, A, or AB horizon has hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 to 3. It is typically silt loam, but silty clay loam is also included. Reaction ranges from moderately acid to slightly alkaline.
The Bt or BA horizon has hue of 10YR or 7.5YR, value of 3 to 6, and chroma of 3 to 6. The lower part of the Bt horizon contains redoximorphic features which have chroma of 2 to 8. Texture is silty clay loam or silt loam. Average clay content ranges from 25 to 35 percent. Reaction ranges from strongly acid to neutral.
The 2Bt horizon has hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 6; and chroma of 3 to 6. Redoximorphic features have chroma of 2 to 8. Texture is loam, sandy loam, clay loam, silty clay loam, silt loam, or sandy clay loam. The gravel content ranges from a few pebbles to 15 percent. Average clay content ranges from 18 to 32 percent, and average fine and medium sand content ranges from 15 to 45 percent. Sand content of individual subhorizons ranges from 10 to 75 percent.
Some pedons have a subhorizon just above the 2C horizon that is enriched in clay and has darker color value than the subhorizon above it. Reaction ranges from moderately acid to slightly alkaline.
The 2C horizon has hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 6; and chroma of 3 to 6. Redoximorphic features have chroma of 2 to 8. The 2C horizon is commonly stratified. Dominant textures are sandy loam, loam, or silt loam, and their gravelly analogs with thin strata of loamy sand or sand. Average clay content ranges from 10 to 20 percent. Average sand content ranges from 15 to 75 percent. Sand content of individual subhorizons ranges from 15 to 95 percent. Coarse fragment content ranges from 2 to 20 percent gravel. Reaction ranges from slightly acid to moderately alkaline. In some pedons, the 2C horizon is in the lower part of the series control section.
COMPETING SERIES: These are the Assumption, Aviston, Barrington, Blackberry, Buckhart, Catlin, Dana, Danabrook, Geryune, Graymont, Harrison, Keltner, Saybrook, and Totanang series. Assumption soils average more than 20 percent clay in the lower part of the series control section. Aviston, Blackberry, Buckhart, Catlin, and Harrison soils do not have horizons with more than 15 percent sand within a depth of 102 cm (40 inches). Barrington soils have carbonates within a depth of 102 cm (40 inches). Dana, Danabrook, Geryune, Graymont, and Saybrook soils have a well graded sand fraction in the lower one-half of the series control section. Keltner soils have a paralithic contact within a depth of 152 cm (60 inches). Totanang soils average more than 75 percent sand in the lower part of the series control section.
GEOGRAPHIC SETTING: Clare soils are on loess covered outwash plains, stream terraces, till plains, kames, and eskers of Wisconsinan Age. These soils formed in 51 to 102 cm (20 to 40 inches) of loess or other silty material and in the underlying loamy stratified outwash. Slope gradients range from 0 to 5 percent. Mean annual air temperature ranges from 8 to 12 degrees C (46 to 53 degrees F). Mean annual precipitation ranges from 760 to 1,140 mm (30 to 45 inches). Frost free days range from 140 to 180. Elevation ranges from 207 to 311 meters (680 to 1,020 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barony, Drummer, Elburn, Millbrook, and Otter soils. The moderately well drained Barony soils are on similar landform positions adjacent to Clare soils and have a dark colored surface layer less than 10 inches thick. The poorly drained Drummer soils are in slight depressions or lower parts of the landform. The somewhat poorly drained Elburn and Millbrook soils are on slightly lower lying landform positions. The poorly drained Otter soils have a mollic epipedon more than 24 inches thick and are on nearby flood plains.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. The depth to an apparent seasonal high water table is 61 to 107 cm (2.0 to 3.5 feet) below the surface at some time between February and April in most years. The potential for surface runoff is negligible to low. Saturated hydraulic conductivity is moderately high or high (4.23 to 14.11 micrometers per second) in the upper part of the solum and moderately high or high (4.23 to 42.33 micrometers per second) in the lower part of the solum and in the substratum. Permeability is moderate in the upper part of the solum and moderate or moderately rapid in the lower part of the solum and in the substratum.
USE AND VEGETATION: Most areas are used for cultivated crops. Principal crops are corn, soybeans, small grain, and hay. Some areas are used for pasture. Native vegetation is prairie grasses.
DISTRIBUTION AND EXTENT: Central and northern Illinois. The extent is small in MLRAs 95B, 108A, and 108B.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: DeKalb County, Illinois, 1998. The name Clare is from the town of Clare, in Dekalb County which is near the type location.
REMARKS: This soil was formerly mapped as Proctor in DeKalb County. Through MLRA update activities these soils were found to be moderately well drained instead of well drained and fit an oxyaquic subgroup rather than a typic subgroup.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - 0 to 28 cm (0 to 11 inches) (Ap and A horizons); argillic horizon - 36 to 155 cm (14 to 61 inches) (Bt1, Bt2, Bt3, 2Bt4, 2Bt5, and 2Bt6 horizons); udic moisture regime.