LOCATION THETFORD MIEstablished Series
TAXONOMIC CLASS: Sandy, mixed, mesic Aquic Arenic Hapludalfs
TYPICAL PEDON: Thetford loamy sand - on a southwest-facing concave slope of 2 percent in a cultivated field. (Colors are for moist soils unless otherwise stated.)
Ap--0 to 6 inches; very dark grayish brown (10YR 3/2) loamy sand, light brownish gray (10YR 6/2) dry; weak fine granular structure; very friable; many fine and medium roots; neutral; abrupt smooth boundary. (6 to 10 inches thick)
E1--6 to 12 inches; dark brown (10YR 4/3) loamy sand; few fine prominent yellowish brown (10YR 5/8) iron accumulations in the lower part; weak fine granular structure; friable; many fine roots; slightly acid; clear wavy boundary.
E2--12 to 24 inches; light yellowish brown (10YR 6/4) loamy sand; common fine distinct yellowish brown (10YR 5/8) and grayish brown (10YR 5/2) iron depletions; weak fine subangular blocky structure; friable; common fine roots; neutral; clear wavy boundary. (Combined thickness of the Bw horizon is 0 to 25 inches)
E and Bt--24 to 50 inches; very pale brown (10YR 8/3) loamy sand (E); common fine distinct dark yellowish brown (10YR 4/4) iron accumulations and common faint light brownish gray (10YR 6/2) iron depletions; single grain; loose; discontinuous, yellowish brown (10YR 5/4) sandy loam horizontal bands (Bt), 1/4 to 3 inches thick; common fine distinct light gray (10YR 6/1) iron depletions (Bt); weak fine subangular blocky structure; friable; few fine roots; clay bridging of sand grains and common faint clay films; neutral; clear wavy boundary. (6 to 36 inches thick)
Bt--50 to 55 inches; yellowish brown (10YR 5/4) loamy sand; common fine distinct brownish yellow (10YR 6/8) iron accumulations and light gray (10YR 6/1) iron depletions; weak fine subangular blocky structure; very friable; clay bridging of sand grains and common faint clay films; neutral; clear wavy boundary. (0 to 6 inches thick)
C--55 to 66 inches; mottled light gray (10YR 6/1), brown (10YR 5/3), and yellowish brown (10YR 5/8) very fine sand; single grain; loose; slight effervescence; slightly alkaline.
TYPE LOCATION: Livingston County, Michigan; about 6 miles north of Fowlerville; 660 feet north and 75 feet east of the center, sec. 9, T. 4 N., R. 3 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to more than 60 inches. It ranges from moderately acid to neutral in the upper part and moderately acid to slightly alkaline in the lower part. Rock fragments, dominantly gravel, range from 0 to 5 percent by volume in the solum.
The Ap horizon has value of 3 or 4, and chroma of 1 to 3. It is sand, fine sand, loamy sand, or loamy fine sand.
The E horizon has hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 3 to 6. It is sand, loamy sand, fine sand, or loamy fine sand.
The E part of the E and Bt horizon has value of 4 to 8, and chroma of 3 or 4. It is sand, fine sand, loamy sand, or loamy fine sand. The Bt part of the E and Bt horizon has hue of 10YR to 5YR, value of 4 to 6, and chroma of 3 to 6. It is sand, loamy sand, loamy fine sand, sandy loam, or fine sandy loam. In those pedons with sandy loam or fine sandy loam bands the control section averages less than 15 percent clay and has less than 50 percent fine sand. It averages sand or loamy sand.. The bands or lamellae are 1/4 to 3 inches thick and have a total thickness of 6 inches or more. Clay bridging of sand grains is evident in the coarser textures and thin clay coatings are apparent in pores, in root channels, and on some of the vertical and horizontal faces of peds.
The C horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 1 to 4. It is very fine sand, fine sand, or sand. Rock fragments, dominantly gravel, range from 0 to 25 percent by volume. Some pedons have layers with finer textures in the C horizon. It is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no competing series. Closely related are the Bixler, Branch, Leola, Markton, Rimer, Riverdale, and Selfridge series. These soils have a finer textured argillic horizon.
GEOGRAPHIC SETTING: Thetford soils are in nearly level or depressional areas in moraines, till plains, lake plains, outwash plains, terraces, and beach ridges of Wisconsinan Age materials. Slope gradients are predominantly 0 to 2 percent but range from 0 to 4 percent. Mean annual precipitation ranges from 28 to 36 inches, and the mean annual temperature ranges from 47 to 50 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: The well drained Oakville and Spinks soils and the somewhat poorly drained Tedrow soils are the most common associates. The poorly or very poorly drained Granby series is associated in some areas.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. The depth to the seasonal high water table ranges from 1 to 2 feet below the surface from February to May. Potential surface runoff is negligible or very low. Permeability is moderately rapid.
USE AND VEGETATION: Thetford soils are cultivated in most areas. Corn, soybeans, wheat, oats, and grass-legume hay are the principal crops. Some areas are idle or used for permanent pasture. Native vegetation was principally mixed hardwoods, with northern red oak, bitternut hickory, red maple, and American elm the dominant species.
DISTRIBUTION AND EXTENT: Southern lower Michigan. The series is of large extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Clinton County, Michigan, 1974.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from the surface to 24 inches (Ap and E
horizons);
Argillic horizon - zone from 24 to 50 inches (B part of E and Bt and
Bt horizons).