LOCATION COUPEE IN+MIEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, active, mesic Ultic Hapludalfs
TYPICAL PEDON: Coupee silt loam, on a convex, 1 percent slope in a cultivated field at an elevation of 745 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 10 inches; black (10YR 2/1) silt loam, very dark brown (10YR 2/2) crushed, very dark grayish brown (10YR 3/2) dry; moderate fine granular structure; friable; neutral, abrupt smooth boundary. (7 to 11 inches thick)
A--10 to 14 inches; black (10YR 2/1) silt loam, very dark brown (10YR 2/2) crushed, very dark grayish brown (10YR 3/2) dry; moderate medium granular structure; friable; moderately acid; clear wavy boundary. (2 to 10 inches thick)
E--14 to 21 inches; brown (10YR 5/3) silt loam; moderate medium and fine subangular blocky structure; friable; many very fine pores with moderate continuity; common distinct very dark brown (10YR 2/2) organic coatings in pores and old root channels; common distinct very dark grayish brown (10YR 3/2) organic coatings on faces of peds; strongly acid; clear wavy boundary. (0 to 12 inches thick)
Bt1--21 to 26 inches; brown (10YR 4/3) clay loam; moderate medium subangular blocky structure; firm; common very fine pores with moderate continuity; common faint dark brown (10YR 3/3) clay films on faces of peds; common distinct very dark grayish brown (10YR 3/2) organic coatings in pores and old root channels; few fine and medium gravel 1/2 inch or less in diameter; moderately acid; clear wavy boundary.
Bt2--26 to 33 inches, dark yellowish brown (10YR 4/4) clay loam; moderate coarse and medium subangular blocky structure; firm; few fine pores with moderate continuity; common faint brown (10YR 4/3) clay films on faces of peds; common distinct dark brown (10YR 3/3) organic coatings in pores; few medium gravel about 1/2 inch in diameter; moderately acid; clear wavy boundary. (Combined thickness of the Bt horizon is 10 to 28 inches.)
2Bt3--33 to 52 inches; brown (7.5YR 4/4) stratified loamy sand, sand, and coarse sand; weak coarse subangular blocky structure and single grain; very friable and loose; few distinct very dark grayish brown (10YR 3/2) clay films on gravel and bridging between sand grains in the upper part; 15 percent gravel and shale fragments; strongly acid; clear wavy boundary. (12 to 30 inches thick)
2C--52 to 98 inches; stratified pale brown (10YR 6/3) fine sand, sand, and very channery sand (50 percent hard fine shale fragments); below 72 inches material is banded light brownish gray (10YR 6/2) sand and brown (7.5YR 4/4) loamy sand containing about 8 percent shale fragments; single grain; loose; strongly acid.
TYPE LOCATION: St. Joseph County, Indiana; about 3 miles east and 1/2 mile north of New Carlisle; 1,620 feet west and 1,440 feet south of the northeast corner of sec. 30, T. 38 N., R. 1 E.; U.S.G.S. Lydick, IN topographic quadrangle; lat. 41 degrees 43 minutes 8.02 seconds N. and long. 86 degrees 27 minutes 14.21 seconds W., NAD 27; UTM Zone 16, 545410 easting and 4618712 northing, NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the solum: 40 to 60 inches
Depth to contrasting material: 30 to 40 inches
Rock fragment content: less than 5 percent gravel and shale in some horizons to as much as 25 percent in others
Series control section: sand fraction throughout the solum is dominantly medium and coarser
Particle-size control section: averages 18 to 30 percent clay
Ap or A horizon:
Hue: 10YR
Value: 2 or 3
Chroma: 1 to 3
Texture: silt loam or loam, or less commonly sandy loam
Reaction: strongly acid to neutral
Some pedons have an EB or an A and B horizon.
E horizon:
Hue: 7.5YR or 10YR
Value: 3 to 5
Chroma: 3 or 4
Texture: silt loam or loam, or less commonly sandy loam
Reaction: strongly acid to neutral
Bt horizon:
Hue: 7.5YR or 10YR
Value: 2 to 5
Chroma: 3 or 4
Texture: loam, sandy clay loam, or clay loam
Reaction: very strongly acid to moderately acid
2Bt horizon:
Hue: 7.5YR or 10YR
Value: 2 to 5
Chroma: 3 or 4
Texture: loamy sand or sand
Reaction: very strongly acid to moderately acid
Some pedons have a 2BC horizon.
2C horizon:
Hue: 7.5YR or 10YR
Value: 4 to 6
Chroma: 3 to 6
Texture: stratified sand, channery sand, loamy sand, or channery loamy sand
Reaction: very strongly acid to moderately acid
COMPETING SERIES: There are no other series in this family. Series in similar families are the Dakota, Door, Lorenzo, Nineveh, Trempealeau, Volinia, Warsaw, and Wea soils. Dakota, Door, Lorenzo, Nineveh, Trempealeau, Volinia, Warsaw, and Wea soils have a base saturation of 50 percent or more in all horizons. Door soils do not have contrasting materials within a depth of 40 inches.
GEOGRAPHIC SETTING: Coupee soils formed in outwash of Wisconsinan Age that is loamy in the upper part and sandy with gravel and shale in the lower part on outwash plains. Slope gradients range from 0 to 6 percent. The material contains black hard shale which originally contained iron sulphates. From the laboratory work it appears that most of the sulphur has been leached from the soil and the shale fragments in the solum. Crystals of iron pyrite have been observed in the lower part of the sola in this soil and other soils associated with it. Mean annual temperature ranges from 48 to 52 degrees F., mean annual precipitation ranges from 30 to 38 inches, frost-free period ranges from 130 to 170 days, and elevation ranges from 580 to 1,020 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Door, Dowagiac, Pinhook, Quinn, and Tracy soils. Door soils are on similar positions. Dowagiac soils have a dark surface layer less than 10 inches thick and are on similar positions. Pinhook and Quinn soils are poorly drained and are on low lying, flat areas. Tracy soils have an ochric epipedon and are on similar or more sloping positions.
DRAINAGE AND PERMEABILITY: Well drained. The potential for surface runoff is negligible to medium. Permeability is moderate.
USE AND VEGETATION: Soils are cropped with corn, soybeans, small grain, and legume grass mixtures as the principal crops. Native vegetation is prairie grasses.
DISTRIBUTION AND EXTENT: MLRA 98 in northern Indiana and possibly southwestern Michigan. The soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: St. Joseph County, Indiana, 1974.
REMARKS: Coupee was established with the correlation of the 1977 St. Joseph County, Indiana soil survey. Coupee series replaced the Door series which was mapped in the published 1950 St. Joseph County, Indiana soil survey. Characterization of this soil as well as other associated soils has been made by the USDA Soils Laboratory at Beltsville, MD. Results show that these soils have low base status that places them into the Ultic Hapludalfs.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from the surface to 14 inches (Ap and A horizons)
Argillic horizon: from 21 to 52 inches (Bt1, Bt2, 2Bt3 horizons)
Udic moisture regime
NASIS Data Mapunit ID 401629 represents the typical pedon.
ADDITIONAL DATA: Lab characterization data is available for the typical pedon (S70IN-141-001) from the National Soil Survey Laboratory, Lincoln, NE. Transect data (T00IN-141-024 and T00IN-141-025) is on file in MLRA project office, Plymouth, Indiana. The two transects show 95 percent Coupee soils and 5 percent Tracy soils.