LOCATION PEWAMO MI+IN OHEstablished Series
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 760 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 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. (8 to 12 inches thick)
A--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 5 inches thick)
Btg1--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 iron oxide accumulation in the matrix; about 2 percent gravel; slightly acid; gradual wavy boundary.
Btg2--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 iron oxide accumulation in the matrix; common medium faint gray (N 5/0) iron depletions in the matrix; about 2 percent gravel; neutral; gradual wavy boundary. (Combined thickness of the Btg horizon is 8 to 37 inches.)
Cg--37 to 60 inches; grayish brown (10YR 5/2) silty clay loam; massive; firm; common medium prominent brownish yellow (10YR 6/6) masses of iron oxide accumulation; 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.; U.S.G.S. 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 ranges from 10 to 17 inches. Depth to the base of the argillic horizon ranges from 28 to 60 inches. Depth to carbonates ranges from 28 to 60 inches. The particle-size control section commonly averages 40 to 50 percent clay, but some pedons average as low as 35 percent. Rock fragments are primarily glacial erratics of mixed lithology. Mean annual soil temperature ranges from 49 to 56 degrees F.
The A or Ap horizon has hue of 10YR, value of 2 or 3 (5 or less dry), and chroma of 1 or 2 (moist or dry). Texture is loam, clay loam, silty clay loam, silt loam, or silty clay. Rock fragment content ranges 0 to 10 percent. Reaction ranges from moderately acid to neutral.
The Btg or Bt horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 4. Texture is clay loam, clay, silty clay, or silty clay loam. Rock fragment content ranges from 1 to 10 percent. Reaction ranges from 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.
The Cg or C horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 4. Texture is clay loam or silty clay loam. Clay content ranges from 27 to 40 percent. Rock fragment content ranges from 1 to 14 percent. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Lippincott and Millsdale series. Lippincott soils have less than 27 percent clay in the lower part of the series control section. Millsdale soils have a lithic contact within a depth of 40 inches.
GEOGRAPHIC SETTING: The Pewamo soils formed in till on moraines and lake plains. Slope gradients range from 0 to 2 percent. Mean annual precipitation ranges from 29 to 40 inches, mean annual temperature ranges from 47 to 54 degrees F., frost-free period ranges from 130 to 180 days, and elevation ranges from 580 to 1,530 feet above 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 PERMEABILITY: Very poorly drained. The potential for surface runoff is negligible to low. Permeability is moderately slow. Depth to an apparent seasonal high water table ranges from 1 foot above the surface to 1 foot below the surface from December to May in normal years.
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.
DISTRIBUTION AND EXTENT: MLRA's 97, 98, 99, and 111 of southern Michigan, central and northwestern Ohio, and central and northern Indiana. The series is of large extent, about 1.8 million acres.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Lenawee County, Michigan, 1957.
REMARKS: The 6/98 revision narrowed the series concept by limiting the parent material to till only, and removing the lacustrine materials from the concept.
More laboratory work, especially thin sections, is needed to determine if clay increases are pedogenic. Overwash phases are recognized.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - from the surface to 13 inches (Ap and A horizons); argillic horizon - from 13 to 37 inches (Btg1 and Btg2 horizons); aquic conditions - from 0 to 60 inches (Ap, A, Btg1, Btg2, and Cg horizons).
ADDITIONAL DATA: Soil Interpretation Record: MI0042, MI0518. Soil characterization data is available from the National Soil Survey Laboratory, Lincoln, NE.