LOCATION TRACE TN+AL KYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, semiactive, thermic Ultic Hapludalfs
TYPICAL PEDON: Trace silt loam on a linear slope of 2 percent under fescue and clover hay at an elevation of about 590 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 3 inches, brown (10YR 4/3) silt loam; weak fine and medium granular structure; very friable; many fine and very fine roots; about 1 percent rounded gravel; moderately acid; abrupt smooth boundary. (5 to 10 inches thick)
BA--3 to 9 inches, dark yellowish brown (10YR 4/4) silt loam; moderate fine subangular blocky structure; friable; common fine and very fine roots; common fine pores; common medium faint brown (10YR 4/3) silt loam filling root channels; about 2 percent rounded gravel; moderately acid; clear smooth boundary. (0 to 8 inches thick)
Bt1--9 to 24 inches, brown (7.5YR 4/4) silt loam; moderate medium subangular blocky structure; friable; common fine roots; common fine pores; few faint strong brown (7.5YR 4/6) clay films on faces of peds; about 2 percent rounded gravel; moderately acid; clear wavy boundary.
Bt2--24 to 35 inches, brown (7.5YR 4/4) silt loam; moderate medium subangular blocky structure; friable; common fine roots; few fine and medium pores; common distinct strong brown (7.5YR 4/6) clay films on faces of peds and lining root channels; about 6 percent rounded gravel; moderately acid; clear wavy boundary. (Combined thickness of the Bt horizon is 18 to 40 inches)
2BC--35 to 38 inches, dark yellowish brown (10YR 4/4) very gravelly silt loam; weak medium subangular blocky structure; friable; common fine roots; about 45 percent rounded gravel; strongly acid; clear wavy boundary. (4 to 8 inches thick)
2C--38 to 80 inches, yellowish brown (10YR 5/4) extremely gravelly loam; single grain; loose; few fine roots; about 65 percent rounded gravel; strongly acid.
TYPE LOCATION: Lewis County, Tennessee Don Graham Farm; USGS Mt. Joy Topographic Quadrangle; (Latitude: 35 degrees 31 minutes 09 seconds N. and Longitude: 87 degrees 20 minutes 57 seconds W., NAD 27.)
RANGE IN CHARACTERISTICS: Depth to bedrock is greater than 5 feet. Solum thickness and depth to rapidly or very rapidly permeable gravelly horizons ranges from 30 to 60 inches. Fragments of gravel range from 0 to 10 percent in the A and Bt horizons, about 15 to 60 percent in the 2BC horizon, and about 60 to 90 percent in the 2C horizon. The fragments are rounded and subrounded chert and range up to about 3 inches in diameter. Each horizon is moderately acid or strongly acid except the surface layer is less acid where limed.
The Ap horizon has hue of 10YR or 7.5YR, value of 3 or 4, and chroma of 3 or 4. Where the value is 3, the horizon is less than 7 inches thick. The texture is silt loam.
The BA horizon has a hue of 10YR or 7.5YR, value of 4, and chroma of 3 to 6. The texture is silt loam.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 4 or 6. Mottles in shades of brown or yellow range from few to many. The texture is silt loam and silty clay loam, except in the lower part, its range includes loam and clay loam.
Many pedons have a 2BC horizon that has colors like the Bt or 2C horizon. The fine earth fraction is loam, silt loam, silty clay loam, or clay loam.
The 2C horizon has hue of 10YR or 7.5YR, value of 4 or 5, and chroma of 3 to 6. The texture is sandy loam, loam, or silt loam. Mottles in shades of brown range from none to common.
COMPETING SERIES: These are the Armour, Barnsdall, Dexter, Dossman, Goodwill and Hicks series in the same family. Armour soils have 35 percent or less gravel in the C horizon and have moderate permeability. Barnsdall, Dexter, Dossman, and Goodwill soils are free of rock fragments in the lower part of the subsoil. Hicks soils have bedrock between 40 to 60 inches from the surface.
GEOGRAPHIC SETTING: Trace soils are on low stream terraces. Local relief above the nearest stream is commonly 10 to 30 feet. Elevation is commonly 425 to 725 feet above mean sea level. Slopes are linear and range from 0 to 5 percent. These soils formed in silty alluvium of probable loess influence underlain by gravelly alluvium. The rounded and subrounded pebbles are dominantly chert. Near the type location, the mean annual precipitation is 53.3 inches, and the mean annual temperature is 58 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Armour and Humphreys soils on terraces, Pruitton, Nolin, and Riverby series on floodplains, Paden soils on higher stream terraces, and Hawthorne and Biffle series on upland hillsides. Humphreys soils have between 15 and 35 percent coarse fragments in the control section. Pruitton soils are fine-loamy. Nolin soils do not have an argillic horizon in the subsoil and have few fragments above 40 inches. Riverby soils are loamy-skeletal. Paden soils have a fragipan in the subsoil. Hawthorne and Biffle soils are moderately deep to hard limestone or a paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability in the solum and rapid to very rapid in the substratum.
USE AND VEGETATION: Most of the areas are used for pasture, hay, soybeans, tobacco, and corn. The native vegetation was mixed hardwoods including oak, elm, hackberry, maple, beech, black walnut, ash, and yellow-poplar.
DISTRIBUTION AND EXTENT: The Highland Rim in Tennessee and possibly Alabama and Kentucky. The series is of moderate extent. Trace soils are named after the nearby Natchez Trace Parkway and Trace Creek
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Hickman County, Tennessee; 1997.
REMARKS:
Diagnostic horizons recognized in this pedon are:
Ochric epipedon - from 0 to 9 inches (Ap horizon)
Argillic horizon - from 9 to 35 inches (Bt horizon)
Trace series was originally mapped as a silt loam phase of the Humphreys series. Later, they were included as a gravelly substratum phase of the Armour series.
ADDITIONAL DATA: Characterization data from NSSL in Lincoln, Nebraska and from University of Tennessee in Knoxville is available for three pedons (S95TN-101-1, S95TN-101-2, S95TN-101-3)