LOCATION KOKOMO                  IN+MI OH

Established Series


The Kokomo series consists of very deep, very poorly drained soils that formed in loamy materials overlying till. Kokomo soils are in depressions on till plains. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 1016 mm (40 inches), and mean annual temperature is about 10.6 degrees C (51 degrees F).

TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Argiaquolls

TYPICAL PEDON: Kokomo silty clay loam, at an elevation of 253 meters (830 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 23 cm (9 inches); very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; weak fine and medium granular structure; friable; few fine roots; neutral; abrupt smooth boundary.

A--23 to 41 cm (9 to 16 inches); black (10YR 2/1) silty clay loam; moderate fine and medium angular blocky structure; firm; few fine roots; neutral; gradual smooth boundary. [Combined thickness of the A horizon is 25 to 61 cm (10 to 24 inches).]

Btg1--41 to 79 cm (16 to 31 inches); dark gray (5Y 4/1) silty clay loam; moderate medium and fine subangular and angular blocky structure; firm; few fine roots; many distinct olive gray (5Y 5/2) clay films on faces of ped; few distinct very dark gray (10YR 3/1) organic coatings in root channels; common medium prominent dark yellowish brown (10YR 4/4) and few medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; neutral; gradual smooth boundary.

Btg2--79 to 127 cm (31 to 50 inches); olive gray (5Y 5/2) silty clay loam; moderate coarse subangular blocky structure; firm; few fine roots; many distinct olive gray (5Y 5/2) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organic coatings in root channels; common coarse prominent strong brown (7.5YR 5/6) and yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; 2 percent rock fragments; neutral; abrupt wavy boundary. [Combined thickness of the Btg horizon is 58 to 114 cm (23 to 45 inches).]

2C--127 to 163 cm (50 to 64 inches); brown (10YR 5/3) loam; massive; friable; 2 percent rock fragments; strongly effervescent; moderately alkaline.

TYPE LOCATION: Howard County, Indiana; 2,475 feet west and 396 feet south of northeast corner of sec. 8, T. 23 N., R. 4 E.; USGS Kokomo East, Indiana topographic quadrangle; lat. 40 degrees 27 minutes 41.85 seconds N. and long. 86 degrees 05 minutes 52.63 seconds W., NAD 83.

Thickness of the mollic epipedon: 25 to 61 cm (10 to 24 inches)
Depth to the base of the argillic horizon: 91 to 178 cm (36 to 70 inches)
Depth to carbonates: 91 to 178 cm (36 to 70 inches)
Particle-size control section: averages 35 to 40 percent clay
Rock fragment content: 0 to 10 percent gravel throughout the series control section

Ap or A horizon:
Hue: 10YR or is neutral
Value: 2, 2.5, or 3
Chroma: 0 to 2
Texture: silty clay loam, clay loam, loam, silt loam, or mucky silt loam
Reaction: strongly acid to neutral

Btg or Bt horizon:
Hue: 10YR to 5Y
Value: 4 to 6
Chroma: 1 or 2 in the upper part, and 1 to 4 in the lower part
Texture: silty clay loam, clay loam, or silty clay
Clay content: 30 to 45 percent
Reaction: moderately acid to neutral

2Cg or 2C horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 to 4
Texture: loam
Clay content: 15 to 24 percent
Calcium carbonate equivalent: 15 to 40 percent
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: These are the Calamine, Grannycreek, Lippincott, and Tanglenook series. Calamine soils have a paralithic contact within a depth of 152 cm (60 inches). Grannycreek are in areas that receive more than 1067 mm (42 inches) of mean annual precipitation. Lippincott soils have more than 10 percent rock fragments in the lower part of the series control section. Tanglenook soils have a mollic epipedon that is thicker than 61 cm (24 inches).

GEOGRAPHIC SETTING: Kokomo soils are in depressions on till plains. Slope ranges from 0 to 2 percent. The soils formed in loamy materials overlying loam till. Mean annual precipitation ranges from 889 to 1067 mm (35 to 42 inches). Mean annual temperature ranges from 8.9 to 12.8 degrees C (48 to 55 degrees F). Frost-free period is 140 to 190 days. Elevation is 162 to 381 meters (530 to 1250 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brookston, Celina, Crosby, Fincastle, Miami, Russell, and Xenia soils. The poorly drained Brookston soils are on similar landforms as the Kokomo soils. The moderately well drained Celina and Xenia soils and the somewhat poorly drained Crosby and Fincastle soils are on swells on till plains. The moderately well drained Miami and well drained Russell soils are on swells and knolls on till plains and on shoulders and backslopes on dissected till plains.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Depth to the top of an apparent seasonal high water table ranges from 30 cm (1.0 foot) above the surface to 15 cm (0.5 foot) below the surface during the winter and spring in normal years. Potential for surface runoff is negligible. Saturated hydraulic conductivity is moderately high or moderately low in the loamy materials, and moderately low in the underlying till. Permeability is moderately slow or slow in the loamy materials and slow in the underlying till.

USE AND VEGETATION: Most areas are used to grow corn, soybeans, oats, wheat, and hay. Some areas are in permanent pasture or woodland. Native vegetation is deciduous hardwood forest of elm, maple, and ash.

DISTRIBUTION AND EXTENT: Mainly in MLRAs 111A and 111D, and to a lesser extent in MLRAs 98, 111B, and 111E in east-central Indiana, southern Michigan, and west-central Ohio. The type location is in MLRA 111A. The series is of moderate extent.


SERIES ESTABLISHED: Cass County, Indiana, 1952.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from the surface to a depth of 41 cm (Ap, A horizons).
Argillic horizon: from a depth of 41 to 127 cm (Btg horizon).
Aquic conditions: redox features directly below the mollic epipedon.

A stony subsoil, gravelly substratum, and stratified substratum phases are recognized, and will likely become new series when the subsets of soil surveys with these phases are updated. Drained and undrained phases are recognized.

ADDITIONAL DATA: Characterization data is available from the Kellogg Soil Survey Laboratory (KSSL), Lincoln, Nebraska for pedons sampled by the Agricultural Experiment Station at Purdue University and at The Ohio State University.

National Cooperative Soil Survey