LOCATION MT. CARROLL IL+IA MN WI
Established Series
Rev. JWS-JCD-AAC
02/2011
MT. CARROLL SERIES
The Mt. Carroll series consists of very deep, well drained soils on loess hills. Slope ranges from 0 to 45 percent. The mean annual temperature is about 8.9 degrees C (48 degrees F), and the mean annual precipitation is about 914 mm (36 inches).
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Mollic Hapludalfs
TYPICAL PEDON: Mt. Carroll silt loam on a south-facing, 2 percent slope in a cultivated field at an elevation of 222 meters (728 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 cm (0 to 7 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine and medium granular structure; friable; common very fine and fine roots; slightly acid (pH 6.2); clear smooth boundary. [18 to 25 cm (7 to 10 inches) thick]
E--18 to 25 cm (7 to 10 inches); dark grayish brown (10YR 4/2) silt loam; moderate medium platy structure; friable; few fine roots; many faint very dark grayish brown (10YR 3/2) organic coatings on faces of peds; few distinct light gray (10YR 7/2) dry, silt coatings on faces of peds; slightly acid (pH 6.2); clear smooth boundary. [8 to 20 cm (3 to 8 inches) thick]
BE--25 to 43 cm (10 to 17 inches); brown (10YR 4/3) silt loam; moderate fine subangular blocky structure; friable; few fine roots; many faint dark brown (10YR 3/3) organic coatings on faces of peds; few faint very dark grayish brown (10YR 3/2) organic coats in root channels; moderately acid (pH 6.0); clear smooth boundary. [0 to 20 cm (0 to 8 inches) thick]
Bt1--43 to 64 cm (17 to 25 inches); dark yellowish brown (10YR 4/4) silt loam; moderate fine and medium subangular blocky structure; friable; few fine roots; many faint brown (10YR 4/3) clay films on faces of peds; few distinct very dark grayish brown (10YR 3/2) organic coatings in root channels; moderately acid (pH 6.0); clear smooth boundary.
Bt2--64 to 99 cm (25 to 39 inches); yellowish brown (10YR 5/4) silt loam; moderate fine and medium subangular blocky structure; friable; few fine roots; common faint brown (10YR 4/3) clay films on faces of peds; common prominent very dark grayish brown (10YR 3/2) organic coatings in root channels; few distinct light gray (10YR 7/2) dry, silt coatings on faces of peds; moderately acid (pH 5.8); gradual smooth boundary.
Bt3--99 to 140 cm (39 to 55 inches); yellowish brown (10YR 5/4) silt loam; weak medium and coarse subangular blocky structure; friable; common faint brown (10YR 4/3) clay films on faces of peds; few distinct light gray (10YR 7/2) dry, silt coatings on faces of peds; moderately acid (pH 5.6); gradual smooth boundary. [Combined thickness of the Bt horizon is 51 to 102 cm (20 to 40 inches).]
BC--140 to 157 cm (55 to 62 inches); yellowish brown (10YR 5/4) silt loam; weak medium prismatic structure; friable; few distinct light gray (10YR 7/2) dry, silt coatings on faces of peds; few fine dark reddish brown (5YR 2.5/2) soft masses of iron-manganese oxides within the matrix; moderately acid; gradual smooth boundary.
C--157 to 203 cm (62 to 80 inches); mixed yellowish brown (10YR 5/4) and pale brown (10YR 6/3) silt loam; massive; friable; few fine distinct light brownish gray (10YR 6/2) iron depletions and few fine faint yellowish brown (10YR 5/6 and 10YR 5/8) masses of oxidized iron in the matrix; common fine and medium black (5YR 2.5/1) soft masses of iron-manganese oxides within the matrix; slightly acid.
TYPE LOCATION: Whiteside County, IL; 2,250 feet south and 720 feet east of the northwest corner of sec. 32, T. 22 N., R. 5 E.; USGS Morrison topographic quadrangle; lat. 41 degrees 51 minutes 09 seconds N. and long. 89 degrees 57 minutes 22 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Thickness of the solum: typically 102 to 127 cm (40 to 50 inches), but ranges from 76 to 203 centimeters (30 to 80 inches).
Thickness of loess: greater than 203 cm (80 inches)
Depth to carbonates: typically greater than 152 cm (60 inches), but are as shallow as 114 cm (45 inches) in some pedons.
Reaction: typically moderately acid to neutral, but ranges to strongly acid in the Bt horizon in some pedons.
Average content of clay in the control section: between 18 and 27 percent
Average content of sand in the control section: 0 to 15 percent
Content of rock frament: less than 1 percent throughout
Ap or A horizon:
Hue: 10YR
Value: 2 or 3 (4 or 5 dry)
Chroma: 1 to 3
Texture: silt loam
E horizon:
Hue: 10YR
Value: 4 to 6
Chroma: 2 to 4
Texture: silt loam
Some pedons do not have E horizon because of erosion and cultivation.
Bt horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 3 to 6
Texture: silt loam
Structure: weak or moderate subangular or angular blocky, structure typically becomes coarser with increasing depth.
Other features: Some pedons have redoximorphic features in the lower part of the Bt horizon.
The BC horizon (where present) is silt loam or silt.
C horizon:
Hue: 2.5Y, 10YR or 7.5YR
Value: 5 or 6
Chroma: 1 to 8
Texture: silt loam or silt
Reaction: moderately acid to moderately alkaline
COMPETING SERIES: These are the
Batavia,
Bowes,
Churchtown,
Deroin,
Downs,
Ella,
Festina,
Frankville,
Gladek,
Greenbush,
Harvard,
Hersey,
Knox,
Luana,
Mannon,
Massbach,
Mellott,
Myrtle,
Nasset,
Newhouse,
Oak Center,
Watkins,
Waubeek, and
Yutan series. Batavia, Deroin, Downs, Harvard, Knox, Luana, Watkins, Waubeek and Yutan soils average 27 to 35 percent clay in the particle size control section. Bowes soils have more than 15 percent rock fragments in the lower part of the series control section. Churchtown, Myrtle, and Newhouse soils have more than 15 percent sand in the upper part of the series control section. Ella and Festina soils are stratified in the lower part of the series control section and average more than 15 percent sand. Frankville, Massbach, Nasset, Oak Center soils have a lithic or paralithic contact at depths less than 152 cm (60 inches). Gladek soils formed in lacustrine sediments. Greenbush and Mannon soils have zones within 152 cm (60 inches) that are frequently saturated for periods longer than one month. Hersey soils have rock fragments in the lower part of the series control section and average more than 15 percent fine or coarser sand. Mellott soils have less than 50 percent silt in a horizon in the lower part of the series control section.
GEOGRAPHIC SETTING: Mt. Carroll soils are on ridgetops and side slopes on loess hills and stream benches. They formed in thick loess deposits. Slope gradients typically are 2 to 15 percent, but range from 0 to 45 percent. Mean annual temperature varies from 7.2 to 12.2 degrees C (45 to 54 degrees F), and mean annual precipitation varies from 760 to 914 mm (30 to 36 inches).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Downs,
Fayette,
Port Byron,
Seaton soils, and
Tama soils. Downs soils are on similar landforms nearby. Port Byron and Tama soils are on similar slopes, but are on broad interstream divides further from the drainageways. Tama soils have a mollic epipedon and contain more clay in the finest part of the Bt horizon. Seaton and Fayette soils are on similar or more sloping areas closer to the drainageways. Fayette soils are Typic Hapludalfs and contain more clay in the finest part of the Bt horizon.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Saturated hydraulic conductivity is moderately high to high (4.23 to 14.11 micrometers per second). Permeability is moderate.
USE AND VEGETATION: Most areas of Mt. Carroll soils with slopes less than 20 percent are cropped. Corn, soybeans, small grain and meadow are the principal crops. Most steeper areas are in meadow for hay or pasture. Native vegetation is prairie grasses and scattered hardwood
trees.
DISTRIBUTION AND EXTENT: LRRs L and M, MLRAs 95B, 104, 105, 108b, and 115C in western Illinois, eastern Iowa, southeastern Minnesota, and southwestern and west-central Wisconsin. Extent is small to moderate.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Henderson County, Illinois, 1947.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon - the zone from the surface to a depth of 43 cm (17 inches);
Argillic horizon - the zone from about 43 to 103 cm (17 to 55 inches) (Bt1 and Bt2 horizons).
The 122 to 183 cm (4 to 6 feet) water table phase of Mt. Carroll has been correlated to the recently established Mannon series.
National Cooperative Soil Survey
U.S.A.