LOCATION WORTHEN IL+IA TN WI

Established Series
Rev. KAG-RAT-AAC
03/2011

WORTHEN SERIES

The Worthen series consists of very deep, well drained, moderately permeable soils on alluvial fans and stream terraces on till plains. These soils formed in silty alluvium. Slope gradients range from 0 to 12 percent. Mean annual precipitation is about 915 mm (36 inches) and mean annual temperature is about 11.1 degrees C (52 degrees F).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Cumulic Hapludolls

TYPICAL PEDON: Worthen silt loam - on a south-facing, convex slope with a gradient of 3 percent in a cultivated field at an elevation of about 142 meters (465 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 23 cm (0 to 9 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; friable; common very fine and fine roots; neutral; abrupt smooth boundary.

A--23 to 51 cm (9 to 20 inches); dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak medium granular structure; friable; few very fine and fine roots; common distinct very dark grayish brown (10YR 3/2) organic coatings on faces of peds; slightly acid; clear smooth boundary. [Combined thickness of the A horizon is 41 to 61 cm (16 to 24 inches).]

AB--51 to 74 cm (20 to 29 inches); dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak fine subangular blocky structure; friable; few very fine and fine roots; common distinct very dark grayish brown (10YR 3/2) organic coatings on faces of peds; neutral; clear smooth boundary. [0 to 25 cm (0 to 10 inches) thick]

Bw1--74 to 104 cm (29 to 41 inches); brown (10YR 4/3) silt loam; weak fine subangular blocky structure; friable; few very fine and fine roots; common discontinuous distinct dark brown (10YR 3/3) organic coatings on faces of peds; few distinct very dark grayish brown (10YR 3/2) organic coatings lining root channels and pores; few continuous distinct very pale brown (10YR 7/3) silt coatings on faces of peds; neutral; clear smooth boundary.

Bw2--104 to 163 cm (41 to 64 inches); dark yellowish brown (10YR 4/4) silt loam; weak fine subangular blocky structure; friable; few very fine and fine roots; few distinct dark brown (10YR 3/3) organic coatings lining root channels and pores; few continuous distinct very pale brown (10YR 7/3) silt coatings on faces of peds; neutral; gradual smooth boundary. [Combined thickness of the Bw horizon is 25 to 91 cm (10 to 36 inches).]

C--163 to 203 cm (64 to 80 inches); yellowish brown (10YR 5/4) silt loam; weak medium subangular blocky structure; friable; neutral.

TYPE LOCATION: Scott County, Illinois; about 2 miles west of Glasgow; 160 feet south and 640 feet west of the northeast corner of sec. 26, T. 13 N., R. 13 W.; USGS Bedford, IL. topographic quadrangle; lat. 39 degrees 33 minutes 00 seconds N. and long. 90 degrees 30 minutes 33 seconds W. NAD 27.

RANGE IN CHARACTERISTICS:
Depth to the base of the cambic horizon: 76 to 203 cm (30 to 80 inches)
Particle-size control section: averages 18 to 24 percent clay and 0 to 15 percent sand.
Thickness of the mollic epipedon: 61 to 91 cm (24 to 36 inches) and extends into the upper part of the Bw horizon in some pedons.
Depth to carbonates: present in the C horizon in some pedons below a depth of 127 cm (50 inches)

Ap and A horizons:
Hue: 10YR
Value: 2 or 3, (4 or 5 dry)
Chroma: 1 to 3
Texture: silt loam
Clay content: averages 12 to 22 percent
Reaction: moderately acid to neutral

Some pedons have an AB or BA horizon.

Bw horizon:
Hue: 10YR or less commonly, 7.5YR
Value: 3 or 4 in the upper part and 4 or 5 in the lower part
Chroma: 2 to 4 in the upper part and 3 to 6 in the lower part
Textuture: silt loam
Clay content: averages 15 to 26 percent
Reaction: moderately acid to neutral in the upper part and slightly acid or neutral in the lower part

Some pedons have a BC horizon. Reaction is slightly acid to slightly alkaline.

C horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 3 to 6
Texture: silt loam
Clay content: averages 15 to 24 percent
Reaction: slightly acid to moderately alkaline

COMPETING SERIES: These are the Allison, Anthon, Huntsville, Ivan, Judson, Kahola, Kennebec, Kenridge, Lindstrom, Napier, Rossville, and Sturkie series. Allison and Judson soils average more than 27 percent clay in the middle part of the series control section. Anthon soils have more than 50 percent sand and 20 percent gravel in the lower part of the series control section. Kennebec and Kenridge soils have mollic epipedons that are more than 91 cm (36 inches) thick. Huntsville soils do not have a cambic horizon. Ivan and Kahola soils have free carbonates within a depth of 102 cm (40 inches). Lindstrom soils average less than 50 percent silt in the lower part of the series control section. Napier and Rossville soils have a drier series control section. Sturkie soils have subhorizons that have more than 15 percent sand.

GEOGRAPHIC SETTING: Worthen soils are on alluvial fans and treads and risers on stream terraces. Slope gradients commonly are 1 to 3 percent, but range from 0 to 12 percent. Worthen soils formed in silty local alluvium. Mean annual temperature ranges from 5.6 to 13.9 degrees C (42 to 57 degrees F), mean annual precipitation ranges from 686 to 1143 mm (27 to 45 inches), frost free days ranges from 140 to 210 days, and elevation ranges from 104 to 415 meters (340 feet to 1360 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coffeen, Drury, Huntsville, Littleton, Otter, and Raddle soils. Coffeen, Huntsville, and Otter soils are on lower landform positions, typically on nearly level flood plains. The somewhat poorly drained Coffeen soils average less than 18 percent clay in the particle-size control section. The Huntsville soils do not have a cambic horizon. The Otter soils are poorly drained. Drury and Raddle soils are on similar landform positions. Drury soils do not have a mollic epipedon and Raddle soils have a mollic epipedon that is less than 61 cm (24 inches) thick. The somewhat poorly drained Littleton soils are on similar or lower postions on stream terraces and alluvial fans.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained.(See Remarks). The potential for surface water runoff is medium. Saturated hydraulic conductivity is moderately high to high (4.23 to 14.11 micrometers per second). Permeability is moderate. The depth to a seasonal high water table is more than 183 cm (6 feet) below the surface.

USE AND VEGETATION: Most areas are used to grow corn, soybeans, and small grain. Some areas are used for forages or pasture, and other areas are used for truck crops. Native vegetation is prairie grasses.

DISTRIBUTION AND EXTENT: In the major river valleys that traverse deep loess areas in Illinois, Iowa, Tennessee, and Wisconsin. Extent is moderate in MLRA's 95B, 104, 105, 108A, 108B, 114B, 115B, and 115C.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Jackson County, Illinois, 1929.

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 approximately 74 cm (29 inches) (Ap, A, and AB horizons); Cambic horizon - the zone from approximately 74 to 163 cm (29 to 64 inches) (the Bw1 and Bw2 horizons). Udic moisture
regime.

Worthen soils are not saturated, within a depth of 183 cm (72 inches), for 1 month or more per year in 6 or more out of 10 years. The moderately well drained phase (SIR IL033) does not meet the Oxyaquic criteria. A cherty phase is recognized in areas that contain more than 15 percent chert throughout the series control section. These phases need to be evaluated as subset soil surveys in which it occurs are updated.

ADDITIONAL DATA: Particle size data are on file for several pedons of the Worthen soils at the NRCS MLRA Office Region 11.

National Cooperative Soil Survey
U.S.A.