LOCATION WASHTENAW               IN+MI WI

Established Series
Rev. PM-SFL-FWS
11/2021

WASHTENAW SERIES

The Washtenaw series consists of deep, poorly drained, slowly and moderately slowly permeable soils formed in recent alluvium and in loamy drift. Slopes range from 0 to 2 percent. Mean annual precipitation is about 37 inches, and mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, active, nonacid, mesic Aeric Fluvaquents

TYPICAL PEDON: Washtenaw silt loam - on a concave slope of less than 1 percent under cultivation. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 10 inches; dark yellowish brown (10YR 3/4) silt loam, brown (10YR 5/3) dry; weak fine and medium granular structure; friable; neutral; abrupt smooth boundary. (6 to 11 inches thick)

C--10 to 24 inches; grayish brown (10YR 5/2) silt loam; common medium distinct yellowish brown (10YR 5/6) mottles; weak fine granular structure; friable; moderate amount of fine sand; slight stratification and platy cleavage; slightly acid; clear wavy boundary. (10 to 34 inches thick)

IIA1b--24 to 35 inches; very dark grayish brown (10YR 3/2) silt loam; moderate medium subangular blocky structure; firm; moderate amount of fine sand; slightly acid; clear wavy boundary. (10 to 20 inches thick)

IIB21tgb--35 to 42 inches; grayish brown (2.5Y 5/2) silty clay loam; common fine distinct yellowish brown (10YR 5/6) mottles; moderate medium angular and subangular blocky structure; firm; few dark concretions; thin clay films on faces of peds; moderate amount of fine sand; slightly acid; gradual wavy boundary.

IIB22tgb--42 to 56 inches; light brownish gray (2.5Y 6/2) clay loam; common fine distinct yellowish brown (10YR 5/6) mottles; moderate medium angular blocky structure; firm; thin clay films on faces of some peds; few fine pebbles; neutral; clear wavy boundary. (The combined thickness of the IIB ranges from 8 to 30 inches.)

IIC--56 to 64 inches; yellowish brown (10YR 5/4) loam; many coarse distinct grayish brown (10YR 5/2) mottles; massive, friable; few fine pebbles; slight effervescence; moderately alkaline.

TYPE LOCATION: Elkhart County, Indiana, about 2 1/2 miles west and 1/2 mile north of Goshen; 200 feet east and 5 feet south of center of sec. 12, T. 36 N., R. 5 E.

RANGE IN CHARACTERISTICS: The profile to a depth of 40 inches ranges from medium acid to mildly alkaline and below 40 inches from slightly acid to moderately alkaline. The thickness of the overwash ranges from 20 to 40 inches.

The Ap horizon has hue of l0YR, value of 3 to 5 and chroma of 2 to 4. It is silt loam or loam. Where present the Al horizon has hue of l0YR, value of 2 to 4 and chroma of l or 2.

The C horizon has hue of l0YR, value of 4 to 6 and chroma of 2 or less. It is silt loam or loam. It has weak or moderate fine or medium granular or subangular blocky structure.

The IIAlb has hue of l0YR, value of 2 or 3 and chroma of l or 2. It is loam, silt loam, silty clay loam, or clay loam. Some pedons have more than one buried A horizon.

The IIBt horizon has hue of l0YR, 2.5Y or 5Y, value of 4 to 6 and chroma of 2 or less. It is clay loam, silty clay loam, or silt loam. Some pedons have cambic IIB horizons instead of argillic horizons.

The IIC horizon has hue of l0YR, 2.5Y or 5Y, value of 4 or 5 and chroma of l to 4. It is loam, sandy clay loam, clay loam, or silty clay loam.

COMPETING SERIES: These are the Bowmansville, Orrville, and Shoals in the same family. Bowmansville soils have redder profiles. Orrville and Shoals soils do not have buried dark colored A horizon.

GEOGRAPHIC SETTING: Washtenaw soils are on nearly level areas in depressions of moraines, till plains, and outwash plains. The soils formed in l0 to 40 inches of recent alluvium overlying drift of Wisconsinan Age. Mean annual precipitation ranges from 32 to 42 inches, and mean annual temperature from 47 to 53 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Miami, Riddles, Wawasee, Morley, and Crosier soils. The Miami, Riddles, Wawasee, and Morley soils are well-drained soils on slopes which surround the poorly drained Washtenaw soils in depressions. The Crosier soils are somewhat poorly drained and are on nearly level and gently rolling topography at a slightly higher elevation.

DRAINAGE AND PERMEABILITY: Poorly drained. Surface runoff is very slow or ponded. Permeability is slow or moderately slow.

USE AND VEGETATION: Mostly cultivated to corn, soybeans, oats, and wheat. A small part is in permanent pasture or woodlots. Native vegetation was deciduous forest and some swamp grasses and sedges.

DISTRIBUTION AND EXTENT: Southern Michigan, central and northern Indiana, western Ohio, southeastern Wisconsin, and northeastern Illinois. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AMHERST, MASSACHUSETTS

SERIES ESTABLISHED: Washtenaw County, Michigan, 1930.

REMARKS: The 1974 draft classified them fine-loamy, mixed, nonacid, mesic Typic Haplaquents. In this draft we propose to change the classification to Aeric Fluvaquents. This soil as mapped in Indiana is mostly Aeric. The pedon in the 1974 official description was incorrectly classified as Typic Haplaquents.

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National Cooperative Soil Survey
U.S.A.