LOCATION SEXTON IL

Established Series
Rev. RDC-JCD-CCC
03/2011

SEXTON SERIES

The Sexton series consists of very deep, poorly drained, slowly permeable soils on outwash plains and stream terraces. They formed in loess or other silty material and in the underlying stratified outwash. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 39 inches (991 mm) and mean annual air temperature is about 54 degrees F.

TAXONOMIC CLASS: Fine, smectitic, mesic Typic Endoaqualfs

TYPICAL PEDON: Sexton silt loam in a cultivated field at an elevation of about 675 feet above MSL. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 8 inches (0 to 20 cm); grayish brown (10YR 5/2) silt loam, light gray (10YR 7/2) dry; moderate very fine granular structure; friable; few very fine roots; few fine distinct sperical black (10YR 2/1) weakly cemented manganese nodules throughout; neutral; clear smooth boundary. (12 to 31 cm or 5 to 12 inches thick)

Eg--8 to 12 inches (20 to 30 cm); gray (10YR 6/1) silt loam; moderate thin platy structure; friable; few very fine roots; few fine distinct brown (10YR 5/3) and common fine prominent yellowish brown (10YR 5/6) masses of oxidized iron and common fine faint dark grayish brown (10YR 4/2) iron depletions in the matrix; few fine prominent spherical black (10YR 2/1) weakly cemented manganese nodules throughout; neutral; abrupt smooth boundary. ( 10 to 31 cm or 4 to 12 inches thick)

Btg/Eg--12 to 16 inches (30 to 41 cm); grayish brown (10YR 5/2) silty clay loam (Btg) with light gray (10YR 7/1) silt loam (Eg); moderate medium subangular blocky structure; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) and common faint grayish brown (10YR 5/2) clay films on faces of peds; common fine faint brown (10YR 4/3) and common fine distinct yellowish brown (10YR 5/4) and (10YR 5/6) masses of oxidized iron in the matrix; common medium distinct spherical black (10YR 2/1) weakly cemented manganese nodules throughout; neutral; clear smooth boundary. (0 to 15 cm or 0 to 6 inches thick)

Btg1--16 to 29 inches (41 to 74 cm); gray (10YR 5/1) silty clay; moderate fine and medium prismatic structure; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) and common faint grayish brown (10YR 5/2) clay films and common distinct light gray (10YR 7/1) dry silt coatings on faces of peds; common fine and medium distinct and prominent yellowish brown (10YR 5/4) and (10YR 5/6) masses of oxidized iron and common fine faint light brownish gray (10YR 6/2) iron depletions in the matrix; common fine and medium irregular black (10YR 2/1) weakly cemented manganese nodules throughout; strongly acid; gradual smooth boundary.

Btg2--29 to 36 inches (74 to 91 cm); gray (10YR 5/1) silty clay loam; moderate medium prismatic structure; firm; few very fine roots; common faint grayish brown (2.5Y 5/2) clay films and common distinct light gray (10YR 7/1) dry silt coatings on faces of peds; common fine and medium distinct and prominent yellowish brown (10YR 5/4) and (10YR 5/6) masses of oxidized iron and common fine faint light brownish gray (10YR 6/2) iron depletions in the matrix; common fine and medium distinct irregular black (10YR 2/1) weakly cemented manganese nodules throughout; strongly acid; clear smooth boundary. (Combined thickness of the Btg horizon is 46 to 76 cm or 18 to 30 inches.)

2BCtg--36 to 45 inches (91 to 114 cm); light brownish gray (10YR 6/2) clay loam; weak coarse prismatic structure; firm; common faint grayish brown (2.5Y 5/2) clay films in root channels and pores; many prominent light gray (10YR 7/1) dry silt coatings on faces of peds; common fine and medium prominent yellowish brown (10YR 5/8) masses of oxidized iron and common fine faint gray (10YR 6/1) iron depletions in the matrix; common fine and medium prominent irregular black (10YR 2/1) weakly cemented manganese nodules throughout; moderately acid; gradual smooth boundary.

2BCt--45 to 60 inches (114 to 152 cm); yellowish brown (10YR 5/4) sandy loam; weak coarse prismatic structure; friable; few faint grayish brown (2.5Y 5/2) clay films in root channels and pores; many prominent light gray (10YR 7/2) dry silt coatings on faces of peds; common fine and medium distinct yellowish brown (10YR 5/4) and (10YR 5/6) masses of oxidized iron and manganese and common fine faint gray (10YR 6/1) iron depletions in the matrix; common fine and medium distinct irregular black (10YR 2/1) weakly cemented manganese nodules throughout; moderately acid; clear smooth boundary. (Combined thickness of the 2BC horizons is 15 to 76 cm or 6 to 30 inches.)

2C--60 to 78 inches (152 to 198 cm); stratified dark yellowish brown (10YR 4/6) loamy sand and gray (10YR 6/1) sandy loam; weak very coarse prismatic structure; very friable; few thin grayish brown (10YR 5/2) clay bridges between sand grains; few fine light gray (10YR 7/2) dry silt coatings on faces of peds; common fine prominent black (10YR 2/1) manganese accumulations throughout; strongly acid; abrupt smooth boundary.

3Cg--78 to 80 inches (198 to 203 cm); 75 percent gray (10YR 6/1) with 25 percent yellowish brown (10YR 5/6) silt loam; firm; massive; friable; few root channels; slightly acid.

TYPE LOCATION: Edgar County, Illinois; 150 feet (46 meters) north and 200 feet (61 meters) west of the southeast corner of sec. 18, T. 12 N., R. 13 W.; USGS Westfield East, Illinois topographic quadrangle; latitude 39 degrees 28 minutes 58.3 seconds N. and longitude 87 degrees 53 minutes 13.4 seconds W.; UTM Zone 16 0423712E 4370737N; NAD 83.

RANGE IN CHARACTERISTICS:
Depth to the base of the argillic horizon: typically more than 40 inches (102 cm)
Depth to carbonates: greater than 60 inches (152 cm)
Depth to horizons with more than 15 percent fine sand or coarser: 30 to 55 inches (76 to 140 cm)
Particle-size control section:averages 35 to 42 percent clay

Ap horizon:
Hue: 10YR
Value: 4 to 6
Chroma: 1 or 2
Texture: silt loam
Rock fragments: none
Reaction: moderately acid to neutral; areas recently limed may range to slightly alkaline

Eg horizon:
Hue: 10YR
Value: 5 to 7
Chroma: 1 or 2
Texture: silt loam
Rock fragments: none
Reaction: very strongly acid to neutral

Btg/Eg horizon (where present):
This horizon has properties similar to the Eg horizon above and the Btg horizon
below. A crushed sample would have texture of silty clay loam.

Btg horizon:
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma:1 or 2
Texture: silty clay loam and silty clay
Rock fragments: none
Reaction: very strongly acid to moderately acid

2BCtg or 2BCt horizon(s):
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 1 to 8
Texture: silty clay loam, clay loam, and sandy loam (greater than 15 percent fine
sand or coarser); may include thin strata of sandy textures
Rock fragments: 0 to 7 percent
Reaction: strongly acid to neutral

2C, 2Cg, and 3Cg horizon(s):
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 1 to 8
Texture: sandy loam, silt loam, loam, or clay loam, commonly stratified; may
include thin strata of sandy textures
Rock fragments: 0 to 15 percent
Reaction: strongly acid to slightly alkaline

COMPETING SERIES: These are the Concord, Elbert, Kampville, Traer, and Weir series. Concord soils are generally less than 40 inches to the base of the argillic horizon. Elbert soils have a lithic or paralithic contact within a depth of 60 inches. Kampville, Traer and Weir soils do not have a lithologic discontinuity in the upper 55 inches of the series control section.

GEOGRAPHIC SETTING: Sexton soils are on outwash plains and stream terraces. Slopes range from 0 to 2 percent. The soils formed in loess or silty material 30 to 55 inches (76 to 140 cm) thick and in the underlying stratified outwash. Mean annual temperature ranges from 50 to 57 degrees F.; mean annual precipitation ranges from 32 to 45 inches (813 to 1143 mm); frost free period ranges from 160 to 200 days; and elevation ranges from 340 to 1020 feet (104 to 311 meters) above sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: The Sexton soils are the poorly drained member of a drainage sequence that includes the well drained Camden soils and the somewhat poorly drained Starks soils. It is also associated with the well drained St. Charles soils and the somewhat poorly drained Kendall soils which are formed in 40 to 60 inches (102 to 152 cm) of loess or silty material and the underlying outwash.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained. The potential for surface runoff ranges from low to medium. Saturated hydraulic conductivity is moderately high to low (0.01 to 1.41 micrometers per second). Saturated hydraulic conductivity is moderately high or moderately low (0.42 to 1.41 micrometers per second). Permeability is slow. A seasonal high water table is within a depth of 1 foot at some time between January and June in normal years. Flooding is typically none or rare, however, a commonly flooded phase is recognized (see remarks).

USE AND VEGETATION: Used largely for growing corn, soybeans, and small grain. Native vegetation is hardwood forest.

DISTRIBUTION AND EXTENT: Illinois and possibly Indiana, Iowa, and Missouri. The extent is moderate in MLRAs 108B, 113, 115A, and 115C.

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

SERIES ESTABLISHED: Shelby County, Illinois, 1939.

REMARKS: With the update of 03/2005, the location of the typical pedon was moved from Edwards County, Illinois to Edgar County, Illinois, the classification was changed to reflect endo-saturation rather than epi-saturation, and the great group was changed from Chromic Vertic to Typic because the LEP for these soils is less than required for soils in the Vertic great group. The pedon at the new location better fits the concept of a non-vertic soil with endo saturation.

A commonly flooded phase of Sexton is presently recognized. This phase will be evaluated during MLRA update to determine if new series is needed.

Diagnostic horizons and features recognized in this pedon are:
ochric epipedon - the zone from the surface of the soil to a depth of 12 inches (0 to 30 cm) (Ap and Eg horizons);
albic horizon - the zone from 8 to 12 inches (20 to 30 cm) (Eg horizon);
argillic horizon - the zone from approximately 12 to 45 inches (30 to 114 cm)(Btg part of Btg/Eg, Btg1, Btg2, and 2BCtg horizons);
aquic conditions - redoximorphic features in all horizons below 8 inches;

National Cooperative Soil Survey
U.S.A.