LOCATION ST. CLAIR MI+IL IN OHEstablished Series
TAXONOMIC CLASS: Fine, illitic, mesic Oxyaquic Hapludalfs
TYPICAL PEDON: St. Clair clay loam, on a 4 percent west-facing slope in an idle field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; brown (10YR 4/3) clay loam, pale brown (10YR 6/3) dry; moderate medium granular structure; friable; many fine roots; about 1 percent gravel; slightly acid; abrupt smooth boundary. (5 to 10 inches thick)
BA--9 to 12 inches; yellowish brown (10YR 5/4) clay; moderate medium subangular blocky structure; firm; many fine roots; many thin clay films in root channels; brown (10YR 4/3) worm casts; common medium distinct yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; about 1 percent gravel; moderately acid; clear wavy boundary. (0 to 6 inches thick)
Bt1--12 to 18 inches; brown (10YR 5/3) clay; moderate medium angular blocky structure; firm; few fine roots; many faint yellowish brown (10YR 5/4) clay films on faces of peds; common medium faint dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; about 1 percent gravel; moderately acid; gradual wavy boundary.
Bt2--18 to 25 inches; brown (10YR 4/3) clay; moderate medium angular blocky structure; firm; few fine roots; many distinct yellowish brown (10YR 5/4) clay films on faces of peds; common medium distinct yellowish brown (10YR 5/6) and faint dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; about 1 percent gravel; neutral; abrupt wavy boundary. (Combined thickness of the Bt horizons is 8 to 22 inches.)
C--25 to 70 inches; brown (10YR 5/3) clay; strong medium angular blocky structure (inherent from till); firm; light gray (10YR 7/2) lime streaks; common medium faint dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; about 1 percent gravel; strongly effervescent; slightly alkaline.
TYPE LOCATION: Washtenaw County, Michigan; about 4 1/2 miles northeast of Dixboro; 2,120 feet south and 72 feet west of the northeast corner of sec. 2, T. 2 S., R. 7 E.; USGS Denton, MI topographic quadrangle; lat. 42 degrees 20 minutes 24 seconds N., and long. 83 degrees 33 minutes 36 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 20 to 48 inches. Depth to carbonates commonly is 18 to 30 inches, but ranges from 9 inches in severely eroded pedons. Mean annual soil temperature is 47 to 52 degrees F.
The upper part of the solum ranges from moderately acid to neutral.
The Ap horizon has hue of 10YR or 7.5YR; value of 3 to 5; and chroma of 2 or 3. Texture is silt loam, silty clay loam, or clay loam. Where severely eroded, texture is silty clay or clay. Content of rock fragments range from 0 to 15 percent. Reaction is moderately acid to neutral.
In uncultivated areas, an A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It is 1 to 3 inches thick.
Some pedons have E horizons. Texture is loam, silt loam, clay loam, or silty clay loam.
The BA horizon has hue of 10YR or 7.5YR; value of 4 or 5; and chroma of 3 or 4. Texture is clay loam, silty clay loam, silty clay, or clay.
The Bt horizon has hue of 10YR or 7.5YR; value of 4 or 5; and chroma of 3 or 4. Texture is silty clay or clay. Clay content is 40 to 60 percent, and averages 50 to 60 percent in the upper 20 inches. Masses of iron accumulation with chroma greater than 2 are present. Iron depletions with chroma of 2 are present in the lower part of the B horizon in some pedons. Reaction is moderately acid to neutral in the upper part and moderately acid to slightly alkaline in the lower part. Content of rock fragments range from 0 to 15 percent.
Some pedons have BC horizons, which may be calcareous.
The C horizon has hue of 10YR or 7.5YR; value of 4 to 6; and chroma of 1 to 4. Texture is silty clay, clay, silty clay loam, or clay loam. Clay content is 35 to 55 percent. Content of rock fragments range from 1 to 15 percent. Reaction is slightly alkaline or moderately alkaline. Some pedons have Cd horizons.
COMPETING SERIES: These are the Alexandria, Brushcreek, Lairdsville, Lucas, Markham, Morley, Ozaukee, and Schoharie soils. Alexandria soils do not have carbonates within 30 inches. Brushcreek and Lairdsville soils have a paralithic or lithic contact in the lower part of the series control section. Lucas soils do not have rock fragments in the series control section. Markham and Morley soils average less than 50 percent clay in the upper 20 inches of the argillic horizon. Ozaukee soils average less than 35 percent clay in the lower part of the series control section. Schoharie soils have hue redder than 7.5YR in the Bt horizon.
GEOGRAPHIC SETTING: St. Clair soils formed in calcareous, moderately fine and fine textured glacial drift on ground moraines, end moraines and lake plains. Slope gradient range from 1 to 12 percent. Elevations are 600 to 1300 feet. Mean annual precipitation is 28 to 36 inches, and mean annual temperature is 45 to 50 degrees F. The frost free period is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Haskins, Hoytville, Mermill, Nappanee and Wauseon soils. St. Clair soils are in a drainage sequence with the somewhat poorly drained Nappanee soils and the very poorly drained Hoytville soils, which have iron depletions in the upper parts. The Nappanee and Hoytville soils are on lower geomorphic positions. Associated soils formed in coarser material overlying fine textured material are the very poorly drained Mermill and Wauseon soils and the somewhat poorly drained Haskins soils on lower landscape positions.
DRAINAGE AND PERMEABILITY: Moderately well drained. A perched seasonal high water table is at a depth of 2 to 3 feet below the surface from March through May in most years. Permeability is slow. The potential for surface runoff is medium on the gentler slopes to high on the steeper slopes.
USE AND VEGETATION: A large part of St. Clair soils have been cleared and are cropped to corn, oats, wheat, soybeans, clover, and alfalfa. A considerable part is in pasture and meadow. Native vegetation included sugar maple, northern red oak, white oak, and white ash.
DISTRIBUTION AND EXTENT: Southern Michigan, northeastern Indiana, northern Illinois, and northwestern Ohio in MLRAs 96, 98, 99, 108, 110, and 111. This series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: St. Clair County, Michigan, 1929.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - from the surface to 9 inches (Ap horizon). Argillic horizon - from 12 to 25 inches (Bt1 and Bt2 horizons). Particle-size control section - the entire argillic horizon, from 12 to 25 inches (Bt1 and Bt2 horizons). Oxyaquic feature - water saturation in one or more layers within 40 inches for one month or more per year in 6 or more out of 10 years. Udic soil moisture regime.
ADDITIONAL DATA: Soil Interpretations Record: MI0010.