LOCATION PEKIN IN+KY OH PAEstablished Series
The Pekin series consists of moderately well drained soils formed in silty alluvium and loess on stream terraces and flood-plain steps. They are very deep soils that are moderately deep or shallow to a fragipan. Slopes range from 0 to 12 percent. Mean annual precipitation is about 1143 mm (45 inches), and mean annual temperature is about 12 degrees C (53 degrees F).
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Aquic Fragiudults
TYPICAL PEDON: Pekin silt loam on a gently sloping area in a cultivated field at an elevation of 221 meters (725 feet) above MSL. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 cm (0 to 9 inches); brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; moderate medium granular structure; friable; many fine roots; neutral; abrupt smooth boundary. (20 to 30 cm or 8 to 12 inches thick)
Bt1--23 to 38 cm (9 to 15 inches); light yellowish brown (10YR 6/4) silt loam; moderate medium subangular blocky structure; friable; many fine roots; many fine pores; common distinct yellowish brown (10YR 5/4) clay films on faces of peds; neutral; clear smooth boundary. (0 to 18 cm or 0 to 7 inches thick)
Bt2--38 to 69 cm (15 to 27 inches); yellowish brown (10YR 5/6) silty clay loam; moderate medium subangular blocky structure; firm; many fine roots; many fine pores; many distinct dark yellowish brown (10YR 4/4) clay films on faces of peds; common medium prominent light brownish gray (10YR 6/2) iron depletions in the matrix; very strongly acid; clear smooth boundary. (13 to 48 cm or 5 to 19 inches thick)
Btx1--69 to 89 cm (27 to 35 inches); yellowish brown (10YR 5/6) silty clay loam; moderate very coarse prismatic structure; firm; few fine roots; few fine pores; many distinct brown (10YR 5/3) clay films on faces of peds; many medium prominent light brownish gray (10YR 6/2) iron depletions in the matrix; brittle; extremely acid; gradual wavy boundary.
Btx2--89 to 112 cm (35 to 44 inches); yellowish brown (10YR 5/4) silt loam; moderate very coarse prismatic structure; firm; many prominent gray (10YR 6/1) clay films on faces of peds; many medium distinct light brownish gray (10YR 6/2) iron depletions in the matrix; brittle; extremely acid; gradual wavy boundary. (Combined thickness of the Btx horizons is 38 to 84 cm or 15 to 33 inches.)
C--112 to 152 cm (44 to 60 inches); yellowish brown (10YR 5/6) silt loam; massive; firm; many medium prominent light brownish gray (10YR 6/2) iron depletions in the matrix; very strongly acid.
TYPE LOCATION: Washington County, Indiana; about 1 mile northeast of the town of Pekin; 2,300 feet south and 1,400 feet west of the northeast corner of sec. 19, T. 1 N., R. 5 E.; USGS South Boston, Indiana topographic quadrangle; lat. 38 degrees 30 minutes 31.2 seconds N. and long. 085 degrees 59 minutes 54.2 seconds W., UTM Zone 16, 587329 easting and 4262730 northing; NAD 83.
RANGE IN CHARACTERISTICS:
Depth to the top of the fragipan: 61 to 97 cm or 24 to 38 inches, except severely eroded pedons can range from 25 to 51 cm or 10 to 20 inches
Depth to the base of the argillic horizon: 102 to 178 cm or 40 to 70 inches
Ap horizon:
Value: 4 to 6
Chroma: 3 to 4
Clay content: 10 to 22 percent
Sand content: 3 to 20 percent
Reaction: very strongly acid to neutral
A horizon, where present:
Value: 4 to 6
Chroma: 2
Texture: silt loam
Clay content: 10 to 22 percent
Sand content: 3 to 20 percent
Reaction: very strongly acid or strongly acid
Bt horizon, and BE (where present):
Value: 5 or 6
Chroma: 3 to 6 and, in some part, redox depletions
Chroma: 1 or 2
Texture: silt loam or silty clay loam
Clay content: 18 to 30 percent
Sand content: 3 to 18 percent sand (less than 15 percent fine and coarser)
Reaction: is very strongly acid or strongly acid, and the upper part ranges to neutral in limed areas
Btx or Btxg horizon, and BC horizon where present:
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 2 to 8
Texture: silt loam or silty clay loam
Clay content: 20 to 32 percent
Sand content: 3 to 18 percent
Rock fragments: 0 to 7 percent gravel
Reaction: strongly acid to extremely acid
C or Cg horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 2 to 6
Texture: silt loam, silty clay loam, or loam, and less commonly sandy loam or fine sandy loam
Clay content: 10 to 30 percent
Sand content: 2 to 70 percent
Rock fragments: 0 to 14 percent gravel
Reaction: very strongly acid or strongly acid, and ranges to neutral in the lower part
COMPETING SERIES: These are the Johnsburg and Needleye series. Johnsburg soils are have redox depletions immediately below the surface layer, and have a lithic contact at 122 to 213 cm or 48 to 84 inches. Needleye soils have rock fragments (chert) in the fragipan.
GEOGRAPHIC SETTING: The Pekin soils are on treads and risers of stream terraces and on flood-plain steps. Slopes range from 0 to12 percent. Pekin soils formed in mixed silty alluvium and loess, with some pedons having loamy alluvium in the lower part of the series control section. The mean annual temperature ranges from 11 to 14 degrees C (51 to 57 degrees F), and the mean annual precipitation ranges from 1016 to 1168 mm (40 to 46 inches). Frost free period ranges from 170 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bartle, Elkinsville, Peoga, and less commonly Vincennes soils. The somewhat poorly drained Bartle soils are on treads. The well drained Elkinsville soils do not have a fragipan and are on treads and risers. The poorly drained Peoga soils are on treads. The poorly drained Vincennes soils have a cambic horizon, and are on treads.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. Saturated hydraulic conductivity is moderately high or high (1.41 to 14.11 micrometers/s) above the above fragipan and low to moderately high (0.07 to 1.41 micrometers/s) in the fragipan. Permeability is moderate above the fragipan and slow or very slow in the fragipan. The potential for surface water runoff is medium to very high. Depth to an intermittent perched seasonal high water table is 0.46 to 0.6 meters (1.5 to 2 feet) in most years, except severely eroded phases are perched at 0.3 to 0.6 meters (1 to 2 feet). These soils on flood-plain steps are subject to rare flooding.
USE AND VEGETATION: Most areas of this soil are being used to grow corn, soybeans, and small grain, mainly wheat. A few areas are used for hay and pasture or are in forest. Native vegetation is mixed hardwood forest.
DISTRIBUTION AND EXTENT: Southern Indiana and Ohio and Pennsylvania. This series has a moderate extent in several MLRA's. Dominantly this series is in MLRA's 114A, 114B, 120B and 122 in Indiana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Washington County, Indiana, 1937.
REMARKS: In 1995 the classification of this series was changed from a Fragiudalf to a Fragiudult. In 1995 the type location was moved to represent a pedon with the base status of a Fragiudult. A severely eroded phase is recognized.
Diagnostic horizons and features recognized in this pedon are:
1) Ochric epipedon: 0 to 23 cm or 0 to 9 inches (Ap horizon)
2) Argillic horizon: 23 to 112 cm or 9 to 44 inches (Bt1, Bt2, Btx1, Btx2 horizons)
3) Fragipan: 69 to 112 cm or 27 to 44 inches (Btx1, Btx2 horizons)
4) Redoximorphic features: 38 to 152 cm or 15 to 60 inches (Bt2, Btx, C horizons)
ADDITIONAL DATA: Lab data available at Agricultural Experiment Station, Purdue University, Station Bulletin 222, file no. OR7708; Station Bulletin 323, file no.'s WS7904 (typical pedon), and JF7922; Station Bulletin 360, file no. LW7808; and Station Bulletin 451, file no. SW8115.