LOCATION HITT ILEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Argiudolls
TYPICAL PEDON: Hitt silt loam. (Colors are for moist soil unless otherwise noted.) Hitt silt loam on a north-facing, linear convex, 2 percent slope in a cultivated alfalfa field at an elevation of 259 meters (850 feet). (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 cm (0 to 9 inches); very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; friable; many fine roots; slightly acid (pH 6.1); clear smooth boundary.
A--23 to 36 cm (9 to 14 inches); very dark brown (10YR 2/2) silt loam, brown (10YR 4/3) dry; moderate fine subangular blocky structure; friable; many fine roots; slightly acid (pH 6.4); clear smooth boundary. [Combined thickness of A horizon ranges from 25 to 48 centimeters (10 to 19 inches)]
Bt1--36 to 46 cm (14 to 18 inches); dark brown (7.5YR 3/3) silty clay loam; moderate medium subangular blocky structure; friable; common fine roots; few distinct dark brown (7.5YR 3/2) clay films on faces of peds; moderately acid (pH 6.0); clear smooth boundary. [10 to 15 centimeters (4 to 6 inches) thick]
2Bt2--46 to 56 cm (18 to 22 inches); dark brown (7.5YR 3/4) clay loam; moderate medium subangular blocky structure; firm; common fine roots; few distinct dark brown (7.5YR 3/2) clay films on faces of peds; 5 percent nonflat subrounded 2 to 20 millimeter mixed rock fragments; moderately acid (pH 5.6); clear smooth boundary.
2Bt3--56 to 69 cm (22 to 27 inches); brown (7.5YR 4/4) clay loam; moderate medium subangular blocky structure; firm; few fine roots; common distinct dark reddish brown (5YR 3/2) clay films on faces of peds; 5 percent nonflat subrounded 2 to 20 millimeter mixed rock fragments; moderately acid (pH 5.9); gradual smooth boundary.
2Bt4--69 to 81 cm (27 to 32 inches); reddish brown (5YR 4/4) clay loam; moderate medium subangular blocky structure; firm; few fine roots; few distinct dark reddish brown (5YR 3/2) clay films on faces of peds; 5 percent nonflat subrounded 2 to 20 millimeter mixed rock fragments; moderately acid (pH 5.9); clear smooth boundary.
2Bt5--81 to 104 cm (32 to 41 inches); reddish brown (5YR 4/4) clay loam; moderate coarse subangular blocky structure; firm; few fine roots; few distinct dark reddish brown (5YR 3/2) clay films on faces of peds; 2 percent nonflat subrounded 2 to 20 millimeter mixed rock fragments and 5 percent flat very angular 2 to 20 millimeter limestone fragments; moderately acid (pH 5.9); abrupt smooth boundary. [Combined thickness of 2Bt horizon ranges from 41 to 61 centimeters (16 to 24 inches)]
3Bt6--104 to 114 cm (41 to 45 inches); reddish brown (2.5YR 4/4) clay; strong medium angular blocky structure; very firm; few fine roots between peds; few distinct dark reddish brown (5YR 3/3) clay films on faces of peds; 5 percent flat very angular 2 to 20 millimeter limestone fragments; neutral (pH 6.6); abrupt smooth boundary. [5 to 25 centimeters (2 to 10 inches) thick]
3R--114 cm (45 inches); broken limestone.
TYPE LOCATION: Winnebago County, Illinois; located about 2200 feet east and 2200 feet south of northwest corner, sec. 36, T. 27 N., R. 10 E. USGS Pecatonica topographic quadrangle; lat. 42 degrees 17 minutes 53 seconds N. and long. 89 degrees 17 minutes 33 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon is 25 to 48 cm (10 to 19 inches). The solum commonly is 102 to 127 cm (40 to 50 inches) thick but ranges to 152 cm (60 inches) thick. Hitt soils formed in thin loess, glacial till and residuum weathered from limestone. The loess typically is 25 to 64 cm (10 to 25 inches) thick and the glacial till from 50 to 102 cm (20 to 40 inches) thick and their combined thickness is about 91 to 127 cm (36 to 50 inches). The depth to limestone bedrock ranges from 102 to 152 cm (40 to 60 inches) and is considered to be a lithic contact. The dominant clay mineral in the loess and upper part of the 2Bt horizon developed from glacial till is snectite. Illite increases with depth in the 2Bt horizon and becomes the dominant clay mineral in the lower part of the 2Bt.
The A1 or Ap horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2.
Commonly a BA horizon or a thin Bt horizon has formed in loess. Typically they have hue of 10YR or 7.5YR, value of 3 to 5, and chroma of 3 or 4. Texture is silty clay loam.
Many of the properties of the 2Bt and 3Bt horizons are believed to have been inherited from an exhumed Paleosol of late Sangamon Age.
The 2Bt horizon has hue of 2.5YR, 5YR, or 7.5YR, value of 3 to 5, and chroma of 3 to 5. Hue of 5YR or redder is present on faces of peds or in the matrix in at least on subhorizon of the 2Bt horizon. The texture of the 2Bt horizon typically is clay loam, but includes thin subhorizons of sandy clay loam in some pedons. The upper 20 inches of the argillic horizon averages between 27 and 35 percent clay and from 15 to 35 percent fine sand or coarser. Reaction of the Bt and 2Bt horizons range from moderately to strongly acid, except in the 3Bt horizon which ranges from neutral to moderately acid.
The 3Bt horizon has formed in residuum weathered from limestone. It commonly has hue of 5YR, value of 3 or 4, and chroma of 3 or 4. In pedons that contain the upper boundary of the 3Bt horizon within 40 inches of the surface, the thickness of the 3Bt horizon is 5 inches or less. Texture is silty clay or clay with a variable content of chert. Clay content commonly ranges from 55 to 70 percent.
COMPETING SERIES: These are the Atkinson, Burchard, Calmar, Cokato, Cresco, Cresent, Durand, Friesland, Griswold, Jasper, Joslin, Keosauqua, Kishwaukee, Marbletown, Moingona, Morrill, Nuxmaruhanixete, Pana, Parmod, Penfield, Reedslake, Ringwood, Rockton, Schoolcraft, Shelby, Sibleyville, Velma, and Winnebago series. All of the soils except Atkinson, Calmar, Marbletown, Rockton, and Sibleyville lack a lithic or paralithic contact within depths of 152 cm (60 inches). Atkinson, Burchard, Cokato, Cresco, Cresent, Friesland, Griswold, Jasper, Keosauqua, Kishwaukee, Marbletown, Moingona, Nuxmaruhanixete, Parmod, Penfield, Reedslake, Ringwood, Schoolcraft, Shelby, and Velma soils lack 5YR or redder hue in the lower solum. Calmar, Rockton, and Sibleyville soils have a lithic or paralithic contact at depths less than 102 cm (40 inches).
GEOGRAPHIC SETTING: Hitt soils are on gently undulating to rolling till plains and moraines which are partially controlled by underlying limestone bedrock. Slope gradient ranges from 1 to 12 percent. These soils formed in Late Sangamon paleosols formed in sandy loam, loam, or clay loam Illinoian glacial till and residuum from weathered limestone bedrock, except the upper 25 to 64 cm (10 to 25 inches) above the 2B is formed in loess. Summers are hot and winters are cold. Mean annual temperature is between 7 and 14 degrees C (45 and 57 degrees F), and mean annual precipitation ranges from 710 to 1020 mm (28 to 40 inches).
GEOGRAPHICALLY ASSOCIATED SOILS: Ogle or Tama soils commonly occur on ridgetops upslope from the Hitt soils where the loess mantle is thicker. Durand and Winnebago soils occur in many places with Hitt soils in similar side slope positions, where the drift is thicker. Dodgeville soils occur on steeper slopes or on similar slopes where glacial deposits do not occur above the bedrock. Hitt is the dark colored member of a biosequence containing Oneco and Woodbine series.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Runoff is low to medium. Saturated hydraulic conductivity is 4.23 to 14.11 micrometers per second (moderate permeability) in the loess and till and 0.42 to 1.41 micrometers per second (slow permeability) in the residuum.
USE AND VEGETATION: Used for cultivated crops such as corn, small grain and meadow crops and for pasture. Native vegetation was prairie grass.
DISTRIBUTION AND EXTENT: LLAs K and M, MLRAs 108B and 95B. Northwestern Illinois and possibly northeastern Iowa, southwestern Minnesota. Known extent is small but believed to be moderate.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Stephenson County, Illinois, 1969.
REMARKS: In minor areas parent material 2 has been slightly influenced by glacial melt water and thus could be identified as glacial drift.
Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 36 cm (14 inches) (Ap and A horizons);
argillic horizon--the zone from a depth of 36 to 114 cm (14 to 45 inches) (Bt1, 2Bt2, 2Bt3 and 2Bt4,
2Bt5, and 3Bt6 horizons);
lithic contact at a depth of 114 cm (45 inches) (Cr horizon).