LOCATION PEWAMO                  MI+IN OH

Established Series
Rev. RWJ-WEF-TJE
11/2021

PEWAMO SERIES

The Pewamo series consists of very deep, very poorly drained soils formed in till on moraines, near-shore zones (relict), and lake plains. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 838 mm (33 inches), and mean annual temperature is about 9.4 degrees C (49 degrees F).

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

TYPICAL PEDON: Pewamo clay loam, on a concave, 1 percent slope in a cultivated field at an elevation of 232 meters (760 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 25 cm (10 inches); very dark brown (10YR 2/2) clay loam, grayish brown (10YR 5/2) dry; weak medium granular structure; firm; 3 percent gravel; slightly acid; abrupt smooth boundary. [20 to 30 cm (8 to 12 inches) thick]

A--25 to 33 cm (10 to 13 inches); very dark brown (10YR 2/2) clay loam; weak medium angular blocky structure; firm; 3 percent gravel; slightly acid; gradual wavy boundary. [0 to 13 cm (5 inches) thick]

Btg1--33 to 64 cm (13 to 25 inches); dark gray (10YR 4/1) silty clay; moderate medium angular blocky structure; firm; many faint dark gray (10YR 4/1) clay films on faces of peds; common medium faint very dark gray (10YR 3/1) organic masses; common medium prominent strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; about 2 percent gravel; slightly acid; gradual wavy boundary.

Btg2--64 to 94 cm (25 to 37 inches); gray (10YR 5/1) silty clay; moderate medium angular blocky structure; firm; many faint gray (10YR 5/1) clay films on faces of peds; common medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common medium faint gray (N 5/) iron depletions in the matrix; about 2 percent gravel; neutral; gradual wavy boundary. [Combined thickness of the Btg horizon is 20 to 94 cm (8 to 37 inches).]

Cg--94 to 152 cm (37 to 60 inches); grayish brown (10YR 5/2) silty clay loam; massive; firm; common medium prominent brownish yellow (10YR 6/6) masses of oxidized iron; common medium faint gray (10YR 6/1) iron depletions; about 4 percent gravel; strongly effervescent; slightly alkaline.

TYPE LOCATION: Washtenaw County, Michigan; about 4 miles northeast of Ypsilanti; 100 feet south and 300 feet west of the northeast corner of sec. 26, T. 2 S., R. 7 E.; USGS Denton topographic quadrangle; lat. 42 degrees 17 minutes 27 seconds N. and long. 83 degrees 33 minutes 56 seconds W., NAD 27; UTM Zone 17, 288494 easting and 4685258 northing, NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon: 25 to 43 cm (10 to 17 inches)
Depth to the base of the argillic horizon: 71 to 152 cm (28 to 60 inches)
Depth to carbonates: 71 to 152 cm (28 to 60 inches)
Particle-size control section: commonly averages 40 to 50 percent clay, but some pedons average as low as 35 percent
Rock fragments: primarily glacial erratics of mixed lithology
Mean annual soil temperature: 9.4 to 13.3 degrees C (49 to 56 degrees F)

A or Ap horizon:
Hue: 10YR
Value: 2 or 3 (5 or less dry)
Chroma: 1 or 2 (moist or dry)
Texture: loam, clay loam, silty clay loam, silt loam, or silty clay
Rock fragment content: 0 to 10 percent
Reaction: moderately acid to neutral

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

Some pedons have a BC, BCg, BCt, or BCtg horizon.

Cg or C horizon:
Hue: 10YR to 5Y
Value: 4 to 6
Chroma: 1 to 4
Texture: clay loam or silty clay loam
Clay content: 27 to 40 percent
Rock fragment content: 1 to 14 percent
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: This is the Millsdale series. Millsdale soils have a lithic contact within a depth of 102 cm (40 inches).

GEOGRAPHIC SETTING: Pewamo soils are on moraines, near-shore zones (relict), and lake plains. Slope ranges from 0 to 2 percent. These soils formed in till. Mean annual precipitation ranges from 737 to 1067 mm (29 to 42 inches). Mean annual temperature ranges from 8.3 to 12.8 degrees C (47 to 55 degrees F). Frost-free period is 130 to 182 days. Elevation is 162 to 466 meters (580 to 1,530 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: The somewhat poorly drained Blount soils, the moderately well drained Glynwood and Morley soils, and the well drained Lybrand soils are in a toposequence with Pewamo soils. They are on swells and higher lying areas. None of these soils have a mollic epipedon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Depth to an apparent seasonal high water table ranges from 30 cm (1 foot) above the surface to 30 cm (1 foot) below the surface from December to May in normal years. The potential for surface runoff is negligible to low. Saturated hydraulic conductivity is moderately high. Permeability is moderately slow.

USE AND VEGETATION: Most areas are used to grow corn, soybeans, small grains, and hay. A small part, especially areas that lack adequate drainage, is in permanent pasture or forest. Native vegetation is forest of red maple, American elm, white ash, and American basswood. See Additional Data section for native vegetative cover in Indiana.

DISTRIBUTION AND EXTENT: MLRAs 97, 98, 99, 111A, 111B, 111C, and 111E of southern Michigan, central and northwestern Ohio, and central and northern Indiana. The series is of large extent, about 1.8 million acres.

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

SERIES ESTABLISHED: Lenawee County, Michigan, 1957.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from the surface to a depth of 33 cm (13 inches) (Ap, A horizons).
Argillic horizon: from a depth of 33 to 94 cm (13 to 37 inches) (Btg horizon).
Aquic conditions: redoximorphic features present in all horizons below the mollic epipedon.

More laboratory work, especially thin sections, is needed to determine if clay increases are pedogenic. An overwash phase is recognized.

A dense substratum phase is currently recognized in MLRA. Further evaluation is needed to determine the presence of densic material in other MLRAs where this series occurs.

06/2016 revision: added wetland veg data from Indiana.

ADDITIONAL DATA: Soil Interpretation Record: MI0042, MI0518. Soil characterization data is available from the National Soil Survey Laboratory, Lincoln, NE.

In Indiana, the native vegetative cover is a forested wetland community commonly inhabited with Green Ash, Pin Oak, Silver Maple, Black Willow, Northern Spicebush, American Elm, Eastern Cottonwood, Ohio Buckeye, Reed Canary Grass, Yellow Nutsedge, Cattail Sedge, Softstem Bulrush and Swamp Milkweed. Source: Indiana State Office, Natural Resources Conservation Service, Indianapolis, IN.

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National Cooperative Soil Survey
U.S.A.