LOCATION PEMBROKE KY+AR MO TNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Mollic Paleudalfs
TYPICAL PEDON: Pembroke silt loam cultivated field. (Color for moist soil.)
Ap--0 to 9 inches; dark brown (7.5YR 3/3) silt loam; weak fine granular structure; friable; common fine roots; neutral; clear wavy boundary.
Bt1--9 to 18 inches; reddish brown (5YR 4/4) silt loam; weak fine subangular blocky structure; friable; common fine and medium roots; common distinct reddish brown (5YR 4/3) clay films on faces of peds; common fine black (10YR 2/1) manganese concretions throughout; neutral; gradual wavy boundary.
Bt2--18 to 28 inches; yellowish red (5YR 4/6) silty clay loam; moderate medium subangular blocky structure; firm, slightly sticky, slightly plastic; common fine roots; common distinct reddish brown (5YR 5/4) clay films on faces of peds; common fine black (10YR 2/1) manganese concretions; moderately acid; gradual wavy boundary.
Bt3--28 to 35 inches; red (2.5YR 4/6) silty clay loam; moderate medium subangular blocky structure; firm, slightly sticky, slightly plastic; common very fine roots; common prominent reddish brown (2.5YR 4/4) clay films on faces of peds; common fine black (10YR 2/1) manganese concretions; moderately acid; gradual wavy boundary.
Bt4--35 to 62 inches; dark red (2.5YR 3/6) silty clay loam; moderate medium subangular blocky structure; firm, slightly sticky, slightly plastic; few very fine roots; few distinct yellowish red (5YR 4/6) silt coats on faces of peds and common prominent reddish brown (2.5YR 4/4) clay films on faces of peds; common fine black (10YR 2/1) manganese concretions; strongly acid; gradual wavy boundary.
Bt5--62 to 80 inches; dark red (2.5YR 3/6) silty clay; moderate medium subangular blocky structure; very firm, moderately sticky, moderately plastic; common prominent reddish brown (2.5YR 4/4) clay films on faces of peds; common fine black (10YR 2/1) manganese concretions; 5 percent chert fragments; strongly acid.
TYPE LOCATION: Warren County, Kentucky: 0.8 mile southeast of Memphis Junction, 0.54 mile east of the intersection of U.S. Highway 31W and Bennett Road, 350 feet north of Bennett Road, in a pasture. USGS Bowling Green South quadrangle; (latitude: 36 degrees, 56 minutes, 8.5 seconds N. and longitude: 86 degrees, 28 minutes, 32.29 seconds W.), NAD83; UTM Zone 16, 546696 easting and 4087868 northing.
RANGE IN CHARACTERISTICS: The solum thickness and depth to bedrock ranges from 60 to more than 120 inches. Reaction ranges from very strongly acid to moderately acid, and commonly is neutral in the surface horizons. Fragments of chert commonly range from 0 to 5 percent by volume in the solum, and can range from 0 to 15 percent in the lower part of the solum in some pedons.
The Ap horizon has hue of 10YR to 5YR, value of 3, and chroma of 2 or 3. Texture is silt loam.
The Bt horizon in the upper part has hue of 5YR or 2.5YR, value of 4 or 5, and chroma of 4 to 8. Texture is silt loam or silty clay loam. The lower part of the horizon has hue of 2.5YR to 10R, value of 3 to 5, and chroma of 4 to 8. Texture is silty clay loam or silty clay.
The BC horizon, where present, has hue of 2.5YR to 10R, values of 3 or 4, and chroma of 4 to 8. Mottles in shades of brown and gray range from none to common. Texture is silty clay loam, silty clay, or clay.
COMPETING SERIES: There are no competing series. The Brinkman and Valton series are closely related, but differ in CEC activity class. The Brinkman and Valton series have a thicker mantle of loess and yellower hues in the upper solum. In addition, mean annual rainfall is less than 35 inches.
GEOGRAPHIC SETTING: Nearly level uplands and karst areas. Slopes commonly are 0 to 2 percent and in some areas can range to 12 percent. These soils formed in a thin silty mantle, presumably loess, and in part in the underlying older alluvium or limestone residuum or both. Near the type location, the mean annual temperature is 56 degrees F. and the mean annual precipitation is 50.9 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baxter, Crider, Vertrees, Elk, Huntington, Newark, Nicholson, and Nolin soils. Baxter soils have more than 35 percent clay and more than 15 percent chert fragments in the subsoil. Crider soils have upper Bt horizons with hues yellower than 5YR, and lacks the darker colored epipedon 7.2 inches or thicker. Vertrees soils have more than 35 percent clay in the upper Bt horizons, redder hues in the upper solum. Elk soils are on stream terraces have B horizons with hue of 7.5YR or yellower, and lacks the darker colored epipedon. The Huntington, Newark, and Nolin soils are on floodplains lack argillic horizons. Nicholson soils are moderately well drained and have a fragipan in the subsoil.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is low. Permeability is moderate to moderately slow.
USE AND VEGETATION: Nearly all of the soil has been cleared. Chief uses are for growing corn, small grains, tobacco, hay, truck crops, fruits, and pasture. The original forest was mixed hardwoods: chiefly oaks, hickory, maple, ash, elm, hackberry, and poplar.
DISTRIBUTION AND EXTENT: MLRAs: 116A, 121, 122. The Pennyroyal and Outer Bluegrass of Kentucky, the Highland Rim of Tennessee, northwest Arkansas, and southwest Missouri. The series is of large extent, about 330,000 acres in size.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Lawrence County, Tennessee, 1955.
REMARKS: Diagnostic horizons recognized in this pedon are:
Mollic intergrade - 0 to 9 inches (Ap horizon)
Argillic horizon - 9 to 80 inches (Bt horizons)