LOCATION HURST IL+MOEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aeric Chromic Vertic Epiaqualfs
TYPICAL PEDON: Hurst silt loam - on a nearly level tread of a lacustrine terrace in a cultivated field at an elevation of about 117 meters (385 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 centimeters (0 to 7 inches); dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak medium granular structure; friable; many very fine roots; common fine and medium distinct spherical black (7.5YR 2.5/1) iron-manganese nodules with sharp boundaries; about 21 percent clay; slightly acid; abrupt smooth boundary. (13 to 23 centimeters or 5 to 9 inches thick)
E--18 to 30 centimeters (7 to 12 inches); brown (10YR 5/3) silt loam, very pale brown (10YR 7/3) dry; moderate medium platy structure parting to weak very fine subangular blocky; friable; common very fine roots; many fine faint light brownish gray (10YR 6/2) iron depletions and common medium faint yellowish brown (10YR 5/4) masses of oxidized iron in the matrix; common fine and medium distinct spherical black (7.5YR 2.5/1) iron-manganese nodules with sharp boundaries; about 22 percent clay; strongly acid; clear smooth boundary (0 to 20 centimeters or 0 to 8 inches thick)
Bt1--30 to 46 centimeters (12 to 18 inches); yellowish brown (10YR 5/4) silty clay loam; moderate fine and medium subangular blocky structure; firm; common very fine roots; common distinct brown (10YR 4/3) clay films on faces of peds; many prominent very pale brown (10YR 8/2) clay depletions on faces of peds; many fine and medium distinct light brownish gray (10YR 6/2) iron depletions and common medium distinct strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; few fine distinct spherical very dark brown (7.5YR 2.5/2) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; about 30 percent clay; very strongly acid; clear smooth boundary. (0 to 18 centimeters or 0 to 7 inches thick)
2Bt2--46 to 71 centimeters (18 to 28 inches); brown (10YR 5/3) silty clay; weak fine prismatic structure parting to weak medium angular blocky; very firm; common very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; many fine faint grayish brown (10YR 5/2) iron depletions and common fine prominent strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; common fine prominent irregular strong brown (7.5YR 4/6) extremely weakly cemented iron-manganese accumulations with clear boundaries; about 43 percent clay; very strongly acid; gradual smooth boundary.
2Btg1--71 to 102 centimeters (28 to 40 inches); grayish brown (2.5Y 5/2) silty clay loam; weak fine prismatic structure parting to weak medium angular blocky; very firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds and few prominent brown (10YR 4/3) clay films lining large channels; few fine and medium prominent strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; few fine prominent irregular strong brown (7.5YR 4/6) extremely weakly cemented iron-manganese accumulations with clear boundaries; about 38 percent clay; very strongly acid; clear smooth boundary.
2Btg2--102 to 135 centimeters (40 to 53 inches); grayish brown (2.5Y 5/2) silty clay; weak medium prismatic structure parting to weak medium angular blocky; very firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common prominent black (N 2.5/) manganese coatings on faces of peds and lining large channels; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron and common fine distinct dark brown (10YR 3/3) masses of oxidized iron and manganese in the matrix; about 46 percent clay; moderately acid; clear smooth boundary.
2Btg3--135 to 157 centimeters (53 to 62 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to weak coarse angular blocky; firm; few very fine roots; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; many coarse prominent irregular black (7.5YR 2.5/1) extremely weakly cemented iron-manganese accumulations with clear strong brown (7.5YR 5/6) boundaries; about 37 percent clay; slightly effervescent; slightly alkaline; clear smooth boundary. (Combined thickness of the 2Bt and 2Btg horizons is 91 to 152 centimeters or 36 to 60 inches.)
2Btkg1--157 to 193 centimeters (62 to 76 inches); olive gray (5Y 4/2) silty clay; weak medium prismatic structure parting to moderate medium angular blocky; very firm; few very fine roots; common distinct olive gray (5Y 4/2) clay films on faces of peds; common distinct very dark brown (7.5YR 2.5/3) masses of oxidized iron and manganese on faces of peds and lining large channels; few fine prominent yellowish brown (10YR 5/4) masses of oxidized iron in the matrix; few fine prominent irregular black (7.5YR 2.5/1) extremely weakly cemented iron-manganese accumulations with diffuse strong brown (7.5YR 5/6) boundaries; common fine and medium prominent irregular white (10YR 8/1) (dry) carbonate concretions; about 45 percent clay; strongly effervescent; slightly alkaline; clear smooth boundary.
2Btkg2--193 to 203 (76 to 80 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to weak medium angular blocky; firm; few distinct dark grayish brown (10YR 4/2) clay films lining vertical channels; common medium prominent strong brown (7.5YR 4/6) masses of oxidized iron along vertical channels; few fine distinct yellowish brown (10YR 5/4) masses of oxidized iron in the matrix; common fine prominent irregular very dark brown (7.5YR 2.5/2) extremely weakly cemented iron-manganese accumulations with diffuse strong brown (7.5YR 5/6) boundaries; about 33 percent clay; slightly alkaline. (Combined thickness of the 2Btkg horizons is 0 to 46 centimeters or 0 to 18 inches.)
TYPE LOCATION: Williamson County, Illinois; about 3 miles east of Hurst;
approximately 1,620 feet north and 1,545 feet west of the southeast corner of
sec. 10, T. 8 S., R. 1 E.; USGS Herrin, IL. topographic quadrangle; lat. 37
degrees 50 minutes 16 seconds N. and long. 89 degrees 4 minutes 59 seconds W.; UTM Zone 16, Easting 316695, Northing 4189855, NAD 83.
RANGE IN CHARACTERISTICS:
Depth of loess or other silty material: 0 to 61 centimeters (0 to 24 inches)
Depth to carbonates: more than 112 centimeters (44 inches)
Depth to the base of the argillic horizon: 112 to more than 203 centimeters (44 to more than 80 inches)
Particle-size control section: averages 35 to 55 percent clay and less than 15 percent sand; some pedons have subhorizons that contain as much as 60 percent clay
Ap or A horizon:
Hue: 10YR
Value: 4 or 5 (6 or 7 dry) Some pedons have an A horizon as much as 13 centimeters (5 inches) in thickness with color value of 3.
Chroma: 2 or 3
Texture: commonly silt loam or less commonly silty clay loam
Clay content: averages 20 to 30 percent and ranges 18 to 35 percent
Sand content: less than 15 percent
Reaction: strongly acid or moderately acid, except pedons that have been limed range to neutral and some eroded pedons range to very strongly acid because of the mixing of subsoil material
E horizon, where present:
Hue: 10YR
Value: 5 or 6 (6 to 8 dry)
Chroma: 2 or 3
Texture: commonly silt loam, but in pedons that have little or no loess is silty clay loam
Clay content: averages 18 to 30 percent
Sand content: less than 15 percent
Reaction: extremely acid to moderately acid, except pedons that have been limed range to slightly acid
BE or Bt horizon, where present:
Hue: 10YR
Value: 4 to 6
Chroma: 3 or 4
Texture: silt loam or silty clay loam
Reaction: extremely acid to moderately acid
2Bt horizon:
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 3 or 4
Texture: silty clay loam, silty clay, or clay
Reaction: extremely acid to moderately acid
2Btg horizon:
Hue: 10YR, 2.5Y or 5Y
Value: 4 to 6
Chroma: 1 or 2
Texture: silty clay loam, silty clay, or clay
Reaction: extremely acid to neutral and ranges to slightly alkaline in the
lower part of some pedons that contain secondary carbonates
2Btkg, 2BCkg, 2BC, 2BCg, 2Cg or 2C horizon:
Hue: 10YR, 2.5Y, or 5Y
Value: 4 to 6
Chroma: 1 to 4
Texture: silty clay loam or silty clay and is stratified in some pedons
Clay content: 27 to 45 percent
Sand content: less than 20 percent
Reaction: very strongly acid to moderately alkaline; carbonates are common, but are not everywhere present
A sandy substratum phase is recognized that is loamy sand or sand in the 3C horizon.
COMPETING SERIES: These are the Ashgrove, Atlas, and Kernan series. Ashgrove and Kernan soils have a mean annual soil temperature less than 56 degrees F. Atlas soils average more than 15 percent sand in the particle-size control section.
GEOGRAPHIC SETTING: Hurst soils are on nearly level or gently sloping treads and sloping risers of lacustrine terraces and lake plains; mainly along major tributaries of the Mississippi River. Some areas are subject to flooding during rare or occasional high flood events. Slopes are dominantly 0 to 5 percent and range to 10 percent. Hurst soils formed in the dominantly clayey lacustrine sediments and have a mantle of loess or other silty material less than 61 centimeters (24 inches) in thickness. The lacustrine sediments in and underlying the Hurst series are weathered to depths of 10 or 12 feet. Below 203 centimeters (80 inches) the stratified lacustrine sediments have coarse structure and widely-spaced cleavage planes, slickensides and pressure faces, clay films on faces of structural units and in channels, segregation of iron-manganese oxides, accumulation of secondary carbonates, and the presence of dark strata. Mean annual air temperature is 12 to 14 degrees C (54 to 57 degrees F), mean annual soil temperature is 13 to 15 degrees C (56 to 59 degrees F), mean annual precipitation is 914 to 1118 millimeters (36 to 44 inches), frost-free period is 180 to 210 days, and the elevation is 104 to 137 meters (340 to 450 feet) above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colp, Geff, Okaw, Ridgway, Redbud, and Wagner series. The moderately well drained Colp soils are on more sloping parts of the same landform. The somewhat poorly drained Geff and well drained Ridgway soils contain less clay and more sand in the particle-size control section and are on stream terraces nearby. The poorly drained Okaw and Wagner soils are on nearly level or slightly depressional treads of the same landform. The Okaw and Colp soils form a hydrosequence with Hurst soils. The moderately well drained Redbud soils occur on slightly higher loess-covered lacustrine terraces nearby.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. The potential for surface water runoff is low or medium. Saturated hydraulic conductivity is moderately high (1.41 to 4.23 micrometers per second) in the silty material and low or moderately low (0.07 to 0.42 micrometers per second) in the clayey lacustrine sediments. Permeability is moderately slow in the silty material and very slow in the clayey lacustrine sediments. In drained areas, depth to an intermittent perched high water table is 15 to 61 centimeters (0.5 foot to 2.0 feet) from January to May in most years.
USE AND VEGETATION: Most areas are cropped to corn, soybeans, and wheat. Some areas are pastured or wooded. Native vegetation is mixed hardwood forest.
DISTRIBUTION AND EXTENT: Southern Illinois and Missouri; extent is moderate, and mainly in MLRA(s) 113, 114B, 115B and 115C.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Williamson County, Illinois, 1952.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon - from the surface of the soil to a depth of 30 centimeters (12 inches), (Ap and E horizons);
Albic horizon - from a depth of 18 to 30 centimeters (7 to 12 inches), (E horizon);
Argillic horizon - from a depth of approximately 30 to 203 centimeters (12 to 80 inches), (Bt1, 2Bt2, 2Btg1, 2Btg2, 2Btg3, 2Btkg1, and 2Btkg2 horizons);
Aquic conditions - periodic episaturation and reduction, indicated by redoximorphic features throughout the soil.
The typical pedon was moved to a new location in the same map unit in 1998.