LOCATION COFFEEN IL+WIEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Fluvaquentic Hapludolls
TYPICAL PEDON: Coffeen silt loam - in a nearly level cultivated field at an elevation of about 420 feet above MSL. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; weak fine granular structure; friable; slightly acid; abrupt smooth boundary.
A--7 to 12 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; friable; moderately acid; clear smooth boundary. (The combined thickness of the A horizons is 10 to 18 inches.)
Bg1--12 to 19 inches; dark grayish brown (10YR 4/2) silt loam; weak medium subangular blocky structure; friable; few faint very dark grayish brown (10YR 3/2) organic coatings on faces of peds; few fine distinct dark brown (7.5YR 3/2) iron and manganese oxide stains on faces of peds; moderately acid; clear smooth boundary. (0 to 10 inches thick)
Bg2--19 to 24 inches; grayish brown (10YR 5/2) silt loam; weak medium subangular blocky structure; friable; many fine distinct brown (7.5YR 4/4) masses of iron accumulation in the matrix; common prominent black (10YR 2/1) and dark reddish brown (5YR 2/2) weakly cemented iron and manganese oxide concretions throughout; moderately acid; gradual smooth boundary.
Bg3--24 to 36 inches; 70 percent light brownish gray (10YR 6/2), 15 percent yellowish brown (10YR 5/8), and 15 percent brown (10YR 5/3) silt loam; weak medium subangular blocky structure; friable; common black (10YR 2/1) weakly cemented iron and manganese oxide concretions throughout; about 5 percent sand; moderately acid; diffuse smooth boundary. (The combined thickness of the Bg horizons is 4 to 44 inches.)
Cg--36 to 50 inches; light brownish gray (10YR 6/2) silt loam stratified with thin lenses of loam; massive; friable; many fine distinct dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; moderately acid; gradual smooth boundary.
C--50 to 80 inches; pale brown (10YR 6/3) stratified loam, silt loam, and sandy loam; massive; friable; common fine distinct yellowish brown (10YR 5/4) and dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; slightly acid.
TYPE LOCATION: Edwards County, Illinois; about 2 miles south of Albion; 495 feet south and 65 feet east of the center of sec. 14, T. 2 S., R. 10 E.; USGS Albion South, IL topographic quadrangle; lat. 38 degrees, 20 minutes, 53 seconds North and long. 88 degrees, 04 minutes, 00 seconds West; NAD 27.
RANGE IN CHARACTERISTICS: The depth to the base of the cambic horizon is commonly 30 to 50 inches but ranges to 64 inches. The mollic epipedon ranges from 10 to 18 inches in thickness. The particle-size control section averages between 12 and 18 percent clay and less than 15 percent fine sand or coarser. The mean annual soil temperature at a depth of 20 inches ranges from 53 to 59 degrees F.
The Ap or A horizon has hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 to 3. Clay content ranges from 15 to 27 percent. Reaction is moderately acid to slightly alkaline. Some pedons have an AB horizon.
The Bw or Bg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 or 3. Some pedons have thin coatings with color value of 3 or 4 and chroma of 2. Other pedons have uncoated sand grains or clay depletions on the faces of the peds. Texture typically is silt loam with 10 to 18 percent clay and less than 15 percent fine sand or coarser. Some pedons have thin lenses of loam or sandy loam. Reaction is neutral to moderately acid.
The C or Cg horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 to 8; and chroma of 1 to 3. It is silt loam, or is stratified silt loam, loam, or sandy loam. Clay content ranges from 5 to 15 percent and sand content ranges from 15 to 65 percent. Reaction is moderately acid to neutral. Some pedons have a buried soil below a depth of 50 inches.
COMPETING SERIES: This is the Coffton series. Coffton soils have mean annual soil temperature ranging from 46 to 52 degrees F., and mean annual air temperature of 46 to 51 degrees F.
GEOGRAPHIC SETTING: Coffeen soils are on flood plains, low stream terraces or benches, toeslopes, and alluvial fans. They formed in silty alluvium. Much of the alluvium is of local origin derived from the nearby loess-covered uplands. Slopes range from 0 to 2 percent. The mean annual air temperature ranges from 52 to 58 degrees F., and mean annual precipitation ranges from 35 to 45 inches, frost free period ranges from 170 to 200 days, and elevation ranges from 340 to 1200 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Birds, Drury, Haymond, Littleton, Raddle, and Worthen series. Birds, Drury, and Haymond soils do not have mollic epipedons. The poorly drained Birds soils are on lower lying parts of the flood plains; the well drained Drury soils are on higher or steeper foot slopes; and the well drained Haymond soils are on natural levees near the stream channels or on parts of flood plains that have better natural drainage. Littleton soils are cumulic and are on slightly higher foot slopes, terraces, or alluvial fans. The well drained Raddle soils are on slightly higher foot slopes and stream terraces. The well drained Worthen soils are cumulic and are on higher foot slopes and stream terraces nearby.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. The potential for surface water runoff is negligible to medium. Permeability is moderate. Saturated hydraulic conductivity is moderately high or high (4.23 to 14.11 micrometers/sec) in the solum and moderately high to very high (4.23 to 42.34 micrometers/sec) in the substratum. These soils have an intermittent seasonal high water table at a depth of 1 to 2 feet below the surface at some time between January and May in most years. These soils are also subject to rare or common flooding for brief periods in the spring.
USE AND VEGETATION: Most areas are used to grow cultivated crops. Corn and soybeans are the principal crops. Some areas are in woodland. Native vegetation is mixed prairie grasses and deciduous trees.
DISTRIBUTION AND EXTENT: Illinois and Wisconsin. Coffeen soils are of moderate extent in MLRAs 108, 113, 114, and 115.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Edwards-Richland Counties, Illinois, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - the zone from the surface of the soil to a depth of approximately 12 inches (Ap, A horizons); cambic horizon - the zone from approximately 12 to 36 inches (Bw, Bg1, Bg2 horizons); fluvaquentic feature - irregular decrease in organic carbon.
Coffeen soils are restricted to the warmer part of the mesic temperature regime.