LOCATION SOUTHWEST INEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, nonacid, mesic Typic Fluvaquents
TYPICAL PEDON: Southwest silt loam, on a concave, 1 percent slope in a cultivated field at an elevation of 820 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 10 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; friable; common very fine and fine roots throughout; slightly acid; clear wavy boundary. (4 to 18 inches thick)
Bg1--10 to 18 inches; dark grayish brown (10YR 4/2) silty clay loam; weak medium subangular blocky structure; friable; common very fine and fine roots throughout; many fine and medium interstitial and tubular pores with moderate continuity; common medium faint brown (10YR 4/3) masses of iron oxide accumulation in the matrix; slightly acid; clear wavy boundary.
Bg2--18 to 23 inches; dark grayish brown (10YR 4/2) silty clay loam; weak medium subangular blocky structure; friable; common very fine and fine roots throughout; common fine and medium interstitial and tubular pores with moderate continuity; common medium faint brown (10YR 4/3) masses of iron oxide accumulation in the matrix; slightly acid; clear wavy boundary. (Combined thickness of the Bg horizon is 6 to 22 inches.)
2Ab--23 to 34 inches; black (10YR 2/1) silty clay loam; moderate fine subangular blocky structure; firm; common very fine and fine roots throughout; neutral; clear wavy boundary. (6 to 12 inches thick)
2Bgb--34 to 45 inches; gray (10YR 5/1) silty clay loam; moderate medium subangular blocky structure; firm; many medium distinct brown (10YR 5/3) and common fine prominent yellowish brown (10YR 5/8) masses of iron oxide accumulation in the matrix; neutral; clear wavy boundary. (11 to 30 inches thick)
3Ab1--45 to 55 inches; very dark grayish brown (10YR 3/2) silty clay loam; weak coarse subangular blocky structure; firm; common medium prominent dark yellowish brown (10YR 4/6) masses of iron oxide accumulation in the matrix; neutral; gradual wavy boundary.
3Ab2--55 to 75 inches; very dark grayish brown (10YR 3/2) silty clay loam; weak thick platy structure; friable; common medium prominent dark yellowish brown (10YR 4/6) masses of iron oxide accumulation in the matrix; neutral; gradual wavy boundary. (Combined thickness of the 3Ab horizon is 0 to 30 inches.)
3Cg--75 to 80 inches; dark gray (5Y 4/1) silt loam; massive; friable; slightly effervescent; slightly alkaline.
TYPE LOCATION: Elkhart County, Indiana; about 3 miles north and 2 miles east of Wakarusa; 129 feet west and 1,167 feet south of the northeast corner of sec. 8, T. 36 N., R. 5 E.; U.S.G.S. Foraker, IN topographic quadrangle; lat. 41 degrees 35 minutes 28 seconds N. and long. 85 degrees 57 minutes 53 seconds W., NAD 27; UTM Zone 16, 586286 easting and 4604903 northing, NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates: 40 to more than 80 inches
Thickness of the overwash and depth to a buried soil: 10 to 40 inches
Rock fragment content: 0 to 5 percent gravel below the overwash
Ap horizon:
Hue: 10YR
Value: 4
Chroma: 2 or 3
Texture: silt loam
Reaction: slightly acid or neutral
A horizon: (where present)
Hue: 10YR
Value: 3
Chroma: 2 or 3
Texture: silt loam
Reaction: slightly acid or neutral
Thickness: less than 7 inches
Bg horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 1 or 2
Texture: silt loam or silty clay loam
Reaction: slightly acid or neutral
2Ab, 2Bgb, or 3Ab horizon:
Hue: 10YR or 2.5Y
Value: 2 to 6
Chroma: 1 or 2
Texture: silty clay loam, silt loam, clay loam, or loam
Reaction: slightly acid to slightly alkaline
3Cg or 3C horizon: (where present)
Hue: 10YR to 5Y
Value: 4 or 5
Chroma: 1 to 4
Texture: loam, silt loam, or clay loam
Reaction: slightly alkaline or moderately alkaline
Calcium carbonate equivalent: 5 to 25 percent
COMPETING SERIES: These are the Birds, Killbuck, Nookachamps, Rafton, and Skagit series. Birds, Nookachamps, Rafton, and Skagit soils do no have a buried soil (Ab) within a depth of 40 inches. The differentiae separating Southwest soils from Killbuck soils is not clearly defined other than for landform position and geographic distribution. Killbuck soils are on flood plains in MLRA 114 and 139.
GEOGRAPHIC SETTING: Southwest soils formed in 10 to 40 inches of recent alluvium overlying glaciofluvial deposits or glaciolacustrine deposits of Wisconsinan Age and are in depressions on moraines, till plains, and outwash plains. Slope gradients range from 0 to 1 percent. Mean annual temperature ranges from 50 to 55 degrees F., mean annual precipitation ranges from 30 to 42 inches, frost-free period ranges from 130 to 180 days, and elevation ranges from 580 to 1,530 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brookston, Crosier, Miami, Morley, Riddles, and Williamstown soils. All of these soils are formed in till. The poorly drained Brookston soils are in depressions on till plains. The somewhat poorly drained Crosier soils are on swells on till plains. The moderately well drained Miami, Morley, and Williamstown soils, and the well drained Riddles soils are on backslopes on swells and knolls surrounding depressions.
DRAINAGE AND PERMEABILITY: Poorly drained. The potential for surface runoff is negligible to low. Permeability is moderate in the recent alluvium and moderately slow in the buried soil. The depth to the top of a seasonal high water table ranges from 0.5 foot above the surface to 1 foot below the surface for some time in normal years.
USE AND VEGETATION: Soils are mostly used to grow corn, soybeans, oats, and wheat. A small part is in permanent pasture or woodlots. Native vegetation is deciduous forest and some swamp grasses and sedges.
DISTRIBUTION AND EXTENT: MLRA 111 and 98 in northern and central Indiana. The soils are of moderate in extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Delaware County, Indiana, 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from the surface to 10 inches (Ap)
Cambic horizon: from 10 to 18 inches (Bg1, Bg2)
Aquic conditions: redoximorphic features present from 10 to 80 inches (Bg1, Bg2, 2Bgb, 3Ab1, 3Ab2, and 3Cg horizons)
Irregular decrease in organic carbon: in the buried horizons from 23 to 80 inches (2Ab, 2Bgb, 3Ab1, 3Ab2, and 3Cg horizons)
Drained (IN0612) and undrained (IN0613) phases are recognized.
NASIS Data Mapunit ID 155046 represents the typical pedon in northern Indiana.
ADDITIONAL DATA: Lab characterization data is available for the typical pedon (S94IN-039-024) from the National Soil Survey Laboratory, Lincoln, NE. Transect data for the typical pedon (T94IN-039-141 is on file in the MLRA project office in Plymouth, Indiana. Transect shows 70 percent Southwest soils, 20 percent Brookston soils, and 10 percent Crosier soils.