LOCATION ST. CHARLES IL+IN WI
Established Series
Rev. GVB-SLE-AAC
02/2011
ST. CHARLES SERIES
The St. Charles series consists of very deep, well drained soils on outwash plains, till plains, or stream terraces. They formed in 40 to 60 inches of loess and in the underlying loamy outwash or sandy loam till. Slope commonly is 0 to 15 percent but ranges from 0 to 30 percent. Mean annual temperature is about 11.1 degrees C (52 degrees F)., and mean annual precipitation is about 889 mm (35 inches).
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Hapludalfs
TYPICAL PEDON: St. Charles silt loam - on an north-facing slope of 3 percent in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 cm (0 to 8 inches); brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; moderate medium granular structure; friable; few fine roots; moderately acid; abrupt smooth boundary. [8 to 25 cm (3 to 10 inches) thick]
Bt1--20 to 38 cm (8 to 15 inches); yellowish brown (10YR 5/4) silty clay loam; moderate fine subangular blocky structure; friable; few fine roots; many faint dark brown (10YR 3/3) organic coatings and dark yellowish brown (10YR 4/4) clay films on faces of peds; moderately acid; clear smooth boundary.
Bt2--38 to 53 cm (15 to 21 inches); yellowish brown (10YR 5/4) silty clay loam; moderate medium subangular blocky structure; friable; few fine roots; many faint dark yellowish brown (10YR 4/4) clay films on faces of peds; moderately acid; clear smooth boundary.
Bt3--53 to 86 cm (21 to 34 inches); yellowish brown (10YR 5/4) silty clay loam; weak medium prismatic structure parting to moderate medium subangular blocky; friable; few fine roots; many faint dark yellowish brown (10YR 4/4) clay films on faces of peds; few fine spherical dark extremely weakly cemented iron-manganese accumulations throughout; moderately acid; clear smooth boundary.
Bt4--86 to 112 cm (34 to 44 inches); yellowish brown (10YR 5/4) silt loam; moderate medium prismatic structure parting to moderate medium subangular blocky; friable; many faint dark yellowish brown (10YR 4/4) clay films and many distinct light gray (10YR 7/2) (dry) silt coatings on faces of peds; common medium distinct brown (7.5YR 4/4) extremely weakly cemented iron-manganese accumulations in the matrix; moderately acid; clear smooth boundary.
Bt5--112 to 127 cm (44 to 50 inches); yellowish brown (10YR 5/4) silt loam; moderate medium subangular blocky structure; friable; many distinct dark yellowish brown (10YR 4/4) clay films and light gray (10YR 7/2) (dry) silt coatings on faces of peds; few fine distinct strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; moderately acid; clear smooth boundary. [Combined thickness of the Bt horizons is 51 to 114 cm (20 to 45 inches).]
2Bt6--127 to 145 cm (50 to 57 inches); yellowish brown (10YR 5/6) stratified loam, sandy loam, and silt loam; weak medium subangular blocky structure; friable; common distinct dark yellowish brown (10YR 4/4) clay films on faces of peds; moderately acid; clear smooth boundary. [10 to 25 cm (4 to 10 inches) thick]
2C--145 to 152 cm (57 to 60 inches); yellowish brown (10YR 5/4) stratified loam and silt loam; massive; friable; moderately acid.
TYPE LOCATION: Bureau County, Illinois; about 2 miles south and 2 1/2 miles east of Wyanet; 80 feet north and 2,170 feet west of the southeast corner of sec. 26, T. 16 N., R. 8 E.; USGS, Wyanet, Illinois, topographic quadrangle: lat. 41 degrees 20 minutes 9 seconds N., and long. 89 degress 32 minutes 12 seconds W., NAD 27; UTM Zone 16T, 0287740 easting, 4579143 northing, NAD 83:
RANGE IN CHARACTERISTICS:
Depth to the base of soil development: 112 to 178 cm (44 to 70 inches)
Depth to free carbonates: greater than 112 cm (44 inches)
Depth to the base of the argillic horizon; greater than 89 cm (35 inches)
Depth to horizons with more than 10 percent sand: 102 to 152 cm (40 to 60 inches)
Particle-size control section: averages between 27 to 35 percent clay and less than 10 percent fine sand or coarser.
Dominant clay mineral in the upper silty layers is smectite and in the lower loamy layers is illite.
Ap or A horizon:
Hue: 10 YR
Value: 3 to 5
Chroma: 1 to 3
Texture: silt loam and silty clay loam in eroded soils
Clay content: 20 to 35 percent
Reaction: strongly acid to slightly alkaline
E horizon (where present):
Hue: 10 YR
Value: 4 to 6
Chroma: typically 3 and less, and commonly of 2 to 4
Texture: silt loam
Reaction: strongly acid to slightly alkaline
B, and/or Bt horizons:
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 3 to 6
Texture: dominantly silty clay loam, but some subhorizons are silt loam
Clay content: 24 to 35 percent
Reaction: moderately acid or strongly acid in at least one subhorizon, and ranges from very strongly acid to neutral.
2Bt, and /or 2BC horizons:
Hue: 10YR or 7.5YR
Value: 4 to 6
Chroma: 3 to 6
Texture: commonly stratified; textures include loam, sandy loam, fine sandy loam, sandy clay loam, clay loam or silt loam. Clay content: 15 to 30 percent
Sand content: 20 to 55 percent with some subhorizons having up to 60 percent sand
Gravel content: 0 to 15 percent
Reaction: strongly acid to neutral
2C horizon:
Hue: 10YR or 7.5YR
Value: 4 to 6
Chroma: 3 to 6
Texture: commonly silt loam, loam, sandy loam, gravelly loam or gravelly sandy loam, and is often stratified.
Clay content: 10 to 25 percent
Sand content: 20 to 60 percent. The content of fine sand plus very fine sand is less than 50 percent of total sand content.
Reaction: moderately acid to moderately alkaline
Volume of rock fragments: less than 20 percent
Other features: Some subhorizons have up to 95 percent sand or up to 80 percent gravel.
Some pedons have subhorizons that are loamy sand and a sandy substratum phase is recognized. Some pedons are sand and gravel in the 2C horizon and a gravelly substratum phase is recognized.
COMPETING SERIES: These are the
Bertrand,
Blackhammer,
Camden,
Dodge,
Dubuque,
Fayette,
Flagg,
Greenridge,
Hackers,
Jackson,
Jemerson,
Knowles,
La Farge,
Lambeau,
Lomira,
Marseilles,
Martinsburg,
Menfro,
Middletown,
Navlys,
Palermo,
Palsgrove,
Pepin,
Piscasaw,
Ridgway,
Rozetta,
Ruma,
Rush,
Russell,
Seaton,
Stookey,
Sylvan,
Thebes, and
Yellowriver series. Dubuque, Knowles, La Farge and Marseilles soils are moderately deep to a lithic or paralithic contact. Bertrand, Jackson, Jemerson, Pepin, Seaton and Stookey soils average less than 27 percent clay in the particle-size control section. Blackhammer soils have rock fragments in the lower part of the series control section that are dominantly chert and sandstone. Camden, Piscasaw, Ridgway and Yellowriver soils have horizons with more than 10 percent sand above a depth of 102 cm (40 inches). Dodge, Lomira, Navlys, and Sylvan soils contain carbonates above a depth of 102 cm (40 inches). Fayette, Menfro, Palermo, Rozetta, Ruma and Stookey soils have less than 10 percent sand throughout the series control section. Flagg soils have at least one subhorizon of the 2Bt horizon that has hue of 5YR or redder on faces of peds or in the matrix. Greenridge soils have soil colors hues of 5Y, 5YG, 10GY, or 5G in the lower part of the series control section. These hues are associated with residuum weathered from galauconitic sandstone. Hackers soils have hues of 2.5YR or 5YR dominant in the solum and throughout the substratum. Lambeau soils have sand or fine sand in the lower part of the series control section. Martinsburg soils have E horizons that are at least 31 cm (12 inches) thick and have the layer of maximum clay content at a depth of 76 to 91 cm (30 to 36 inches). Middletown soils average more than 60 percent sand and less than 10 percent clay in the substratum. Palsgrove soils formed in loess and residuum weathered from limestone and have a lithic contact at depths of 102 to 152 cm (40 to 60 inches). Rush soils have less than 10 percent clay and average more than 20 percent rock fragments in the lower part of the series control section. Thebes soils have more than 15 percent sand in all horizons within a depth of 102 cm (40 inches).
GEOGRAPHIC SETTING: St. Charles soils are on summits and side slopes of loess covered outwash plains, till plains, and stream terraces. Slopes commonly are 0 to 15 percent, but some are as steep as 30 percent. St. Charles soils formed in 102 to 152 cm (40 to 60 inches) of loess and in the underlying loamy stratified outwash or sandy loam till thought to be of Wisconsin Age. The substratum commonly is stratified loamy outwash, but in some pedons is gravelly or sandy outwash or sandy loam till. Mean annual temperature ranges from 7.8 to 12.2 degrees C (46 to 54 degrees F), mean annual precipitation ranges from 762 to 1067 mm (30 to 42 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
Batavia,
Camden,
Kendall,
Kidder,
Mchenry,
Sexton,
Starks, and
Thorp soils. Batavia soils have a dark-colored surface layer and commonly are upslope from St.
Charles soils and farther from the drainageways. Camden soils are nearby on similar landscapes that have a mantle of loess 51 to 102 cm (20 to 40 inches) in thickness. Kendall soils are the somewhat poorly drained member of a hydro-sequence with St. Charles soils. Kidder and McHenry soils formed in sandy loam till on similar topographic positions as some St. Charles soils, but average more than 15 percent fine sand and coarser in the control section. The poorly drained Sexton and somewhat poorly drained Starks soils are on outwash plains and stream terraces nearby, and have chroma of 2 in the upper part of the sola. The nearly level, poorly drained Thorp soils have a thinner mantle of loess and are Argiaquic Argialbolls.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. An apparent water table is at a depth of 107 to 183 cm (3.5 to 6 feet) at some time between February and June, or at depths greater than 183 cm (6 feet). The potential for surface runoff is very low on areas of less than 5 percent slopes and low on areas of 5 to 20 percent slopes. Saturated hydraulic conductivity is moderately high to high (4.23 to 14.11 micrometer per second). The areas of St. Charles series mapped as sandy and gravelly substratum phases have saturated hydraulic conductivity in the substratum as high to very high (42.34 or more micrometers per second). Permeability is moderate in the solum. The permeability is moderate in the 2C horizon of soils with loamy substratum, rapid in the 2C horizon of soils in the sandy substratum phase, and very rapid in the 2C horizon of soils in the gravelly substratum phase.
USE AND VEGETATION: Many areas are cultivated. The principal crops are corn, soybeans, small grain, and meadow. Some areas are in pasture or woodland. The soils formed under forest vegetation.
DISTRIBUTION AND EXTENT: Illinois, Indiana, and Wisconsin in MLRAs 95B, 108A, 108B, 110, 111D, and 115C. The extent is large.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Kendall County, Illinois, 1941.
REMARKS: The areas of St. Charles soils mapped as sandy substratum phase and gravelly substratum phase are being evaluated during MLRA update activities to determine if new series are needed. A moderately wet phase with a 107 to 183 cm (3.5 to 6.0 feet) seasonal water table may also be identified in future MLRA updates.
Also, those areas of St. Charles soils that formed in loess and sandy loam till are being evaluated as part of the MLRA 95B update. A new series will be proposed for those soils.
The areas of these soils mapped in "cool mesic" and in "warm mesic" will be evaluated for possible new series.
Diagnostic horizons recognized in this pedon are: ochric epipedon - the zone from the surface to a depth of 20 cm (8 inches) (Ap horizons); argillic horizon - the zone from approximately 20 to 112 cm (8 to 44 inches) (Bt1, Bt2, and Bt3 horizons).
National Cooperative Soil Survey
U.S.A.