LOCATION THOMAS MIEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, calcareous, mesic Histic Humaquepts
TYPICAL PEDON: Thomas muck - on a nearly level area in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Oap--0 to 9 inches; black (10YR 2/1) broken face and rubbed sapric material; moderate medium granular structure; friable; many fine roots; neutral; abrupt smooth boundary. (8 to 15 inches thick)
B1g--9 to 17 inches; dark gray (10YR 4/1) clay loam; many medium prominent yellowish brown (10YR 5/6) mottles; weak coarse subangular blocky structure; firm; 3 percent pebbles; 1 percent cobbles; common fine roots; slight effervescence; mildly alkaline; clear wavy boundary. (4 to 9 inches thick)
C1g--17 to 38 inches; gray (10YR 5/1) clay loam; many medium prominent yellowish brown (10YR 5/6, 5/8) mottles; weak medium subangular blocky structure; firm; 2 percent pebbles; 1 percent cobbles; few fine roots; strong effervescence; moderately alkaline; abrupt wavy boundary. (10 to 24 inches thick)
C2g--38 to 60 inches; gray (10YR 6/1) loam; many coarse prominent yellowish brown (10YR 5/6) and few medium distinct light yellowish brown (10YR 6/4) mottles; massive; friable; 4 percent pebbles; 1 percent cobbles; slight effervescence; moderately alkaline.
TYPE LOCATION: Gratiot County, Michigan; about 1 mile west of Ithaca; 1,950 feet east and 550 feet south of the northwest corner of sec. 2, T. 10 N., R. 3 W.
RANGE IN CHARACTERISTICS: The thickness of the solum is typically 14 to 24 inches but the extreme range is 10 to 24 inches. Coarse fragments range from 0 to 15 percent throughout the mineral horizons. Mean annual soil temperature ranges from 47 to 52 degrees F.
The Oa horizon has hue of 10YR, value of 2 or 3 and chroma of 1 or 2. It is N 2/0 in some pedons. It is muck, mucky sandy loam, mucky silt loam or mucky loam. It ranges from neutral to moderately alkaline.
The B1g horizon has hue of 10YR or 2.5Y, value of 4 through 6 and chroma of 1 or 2. It is clay loam, sandy clay loam, loam, silt loam or silty clay loam. It is mildly or moderately alkaline with slight or strong effervescence.
The C horizon has hue of 5YR, 7.5YR or 10YR, value of 4 through 6 and chroma of 1 through 4. It is clay loam, loam, silt loam, sandy clay loam or silty clay loam. Some pedons contain strata of silty clay, silty loam or sand.
COMPETING SERIES: There are no other series in the same family.
GEOGRAPHIC SETTING: Thomas soils are on nearly level till plains and lake plains. Slope gradients range from 0 to 2 percent. They formed in organic materials less than 16 inches thick overlying calcareous loamy glacial till or lacustrine materials. Mean annual temperature ranges from 45 to 50 degrees F., and mean annual precipitation ranges from 28 to 34 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: Thomas soils are associated in the landscape with Parkhill soils. Parkhill soils lack the organic surface layer that is present in the Thomas soils.
DRAINAGE AND PERMEABILITY: Poorly or very poorly drained. Surface water runoff is very slow to ponded. Permeability is slow or moderately slow.
USE AND VEGETATION: Most areas of this soil are used for pasture or are in woodland. A few small areas are used for the production of corn, small grain and hay.
DISTRIBUTION AND EXTENT: Southern part of the Lower Peninsula of Michigan. The series is of small extent with roughly 7,000 acres mapped.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Tuscola County, Michigan, 1926.