LOCATION LITTLETON IL+MNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Cumulic Hapludolls
TYPICAL PEDON: Littleton silt loam - on a south-facing slope of about 2 percent in a cultivated field at an elevation of 555 feet above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak fine granular structure; friable; few thin very dark gray (10YR 3/1) organic films on faces of peds; neutral; clear smooth boundary.
A--6 to 19 inches; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; moderate fine granular structure; friable; neutral; clear smooth boundary. (Combined thickness of the A horizons is 15 to 26 inches.)
AB--19 to 32 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak very fine subangular blocky structure; friable; common faint dark brown (10YR 3/3) coatings of very fine sand and few dark stains (iron oxides) on faces of peds; neutral; clear smooth boundary. (0 to 18 inches thick)
Bw1--32 to 38 inches; brown (10YR 4/3) silt loam; weak medium subangular blocky structure; friable; common thin dark grayish brown (10YR 4/2) clay linings in pores and root channels; common fine faint dark grayish brown (10YR 4/2) iron depletions; neutral; clear smooth boundary.
Bw2--38 to 49 inches; brown (10YR 5/3) silt loam; weak medium angular blocky structure; friable; few fine faint grayish brown (10YR 5/2) iron depletions and few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; few fine concretions and few fine stains (iron and manganese oxides); slightly alkaline; gradual smooth boundary. (Combined thickness of the Bw horizons is 6 to 34 inches.)
C--49 to 60 inches; brown (10YR 5/3) silt loam; massive; friable; few thin lenses of sand at depths greater than 55 inches; few fine faint grayish brown (10YR 5/2) iron depletions and few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; few fine concretions (iron and manganese oxides); slightly alkaline.
TYPE LOCATION: Knox County, Illinois; about 14 miles south and 9 miles east of Galesburg; 950 feet west and 1735 feet south of the northeast corner of sec. 30, T. 9 N., R. 3 E.; USGS Fairview topographic quadrangle; lat. 40 degrees 44 minutes 20 seconds N. and 090 degrees 12 minutes 01 second W.
RANGE IN CHARACTERISTICS: The solum typically is between 35 and 50 inches in thickness, but ranges from 30 to 62 inches. It is moderately acid to slightly alkaline. Littleton soils typically do not have free carbonates within a depth of 60 inches or more. The mollic epipedon is 24 to 36 inches in thickness and extends into the upper part of the Bw horizon in some pedons. Some pedons have as much as 15 inches of recent overwash. The 10 to 40 inch particle-size control section averages between 22 and 27 percent clay.
The upper part of the series control section (Ap or A horizon) has hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 to 3. Overwash sediments have value of 4 or 5 and chroma of 2 or 3.
Some pedons have a BA horizon rather than an AB horizon.
The middle part of the series control section (Bw horizon) has hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 2 or 3. Chroma of 2 is in the upper part either as iron depletions or in the color of the matrix. This horizon typically is mottled, and contains reddish or brownish stains of iron and manganese oxides. The Bw horizon typically is silt loam but thin subhorizons that are silty clay loam are in some pedons. It commonly contains about 22 percent clay, but individual subhorizons contain 18 to 30 percent clay. The Bw horizon typically has weak or moderate angular or subangular blocky structure.
The lower part of the series control section (C horizon) has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 to 4. Mottles or intermingled colors have hue of 7.5YR, 10YR, 2.5Y, or 5Y; and value and chroma of 4 or 6. The C horizon typically is silt loam to a depth of 60 inches, but some pedons contain thin subhorizons of silty clay loam that contain less than 30 percent clay.
COMPETING SERIES: These are the Ely, Lawson and Smithland series. The Ely soils average more than 27 percent clay in the series control section. The Lawson soils do not have a cambic horizon. The Smithland soils have mollic epipedons that are more than 36 inches thick.
GEOGRAPHIC SETTING: Littleton soils are on alluvial fans, toe slopes of uplands, and stream terraces. Slope gradients commonly are 2 percent or less, but range to as steep as 5 percent. These soils formed in silty alluvium. Mean annual temperature ranges from 46 to 56 degrees F., mean annual precipitation ranges from 32 to 40 inches, frost free period ranges from 150 to 200 days, and elevation ranges from 340 to 1360 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coffeen, Huntsville, Lawson, Raddle, Sawmill and Worthen soils. The somewhat poorly drained Coffeen soils are on similar or slightly lower parts of the landscape. The moderately well drained and well drained Huntsville and somewhat poorly drained Lawson soils are on the flood plains below Littleton soils or, in some places, on narrow flood plains upstream from alluvial fans. The moderately well drained and well drained Worthen and Raddle soils are typically on higher or more steeply sloping parts of similar landscape positions. Raddle soils have a mollic epipedon less than 24 inches in thickness. The poorly drained Sawmill soils are on flood plains below Littleton soils. They are mottled in the mollic epipedon.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff potential is low to medium. Permeability is moderate.
USE AND VEGETATION: Most areas of Littleton soils are cultivated. Corn, soybeans, and small grain are the principal crops. Forages for hay or pasture are grown in some places. Native vegetation is prairie grass.
DISTRIBUTION AND EXTENT: In and along the valleys of the major rivers and their tributary streams in Illinois and Minnesota. Extent is moderate.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Schuyler County, Illinois, 1930.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon (cumulic) - the zone from the surface of the soil to a depth of 32 inches (Ap, A, and AB horizons); cambic horizon - the zone from a depth of 32 to 49 inches (Bw1 and Bw2 horizons).