LOCATION BONNERDALE AREstablished Series
TAXONOMIC CLASS: Coarse-loamy, siliceous, active, thermic Aquic Hapludults
TYPICAL PEDON: Bonnerdale fine sandy loam, 4 percent slope, forested. (Colors are for moist soils unless otherwise stated.)
A--0 to 5 inches; brown (10YR 4/3) fine sandy loam; weak medium granular structure; very friable; many fine and medium roots; extremely acid; clear smooth boundary. (3 to 6 inches thick)
BE--5 to 19 inches; yellowish brown (10YR 5/8) fine sandy loam; common medium distinct light brownish gray (10YR 6/2) mottles; weak medium subangular blocky structure; very friable; many fine and medium roots; few fine Fe-Mg concretions; extremely acid; clear smooth boundary. (8 to 16 inches thick)
Bt--19 to 34 inches; yellowish brown (10YR 5/8) loam; common medium distinct light brownish gray (10YR 6/2) mottles; moderate medium subangular blocky structure; friable; thin patchy clay films on faces of peds; few fine Fe-Mg concretions; extremely acid; gradual smooth boundary.
Btx1--34 to 45 inches; mottled, strong brown (7.5YR 5/6) and light brownish gray (10YR 6/2) fine sandy loam; moderate medium subangular blocky structure; firm, compact and brittle in about 35 percent of mass; thin patchy clay films of faces of peds; few fine and medium roots; few fine Fe-Mg concretions; about 2 percent by volume sandstone gravel; extremely acid; gradual smooth boundary.
Btx2--45 to 54 inches; mottled, strong brown (7.5YR 5/8) and light brownish gray (10YR 6/2) loam; moderate medium subangular block structure; firm, compact and brittle in about 35 percent of mass; thin patchy clay films on faces of peds; few Fe-Mg concretions; few fine and medium roots; about 2 percent by volume sandstone gravel; extremely acid; clear smooth boundary. (Combined thickness of Bt horizon is 29 to 38 inches.)
2Cg--54 to 59 inches; gray (10YR 6/1) clay loam; massive; firm; few fine and medium roots; few fine Fe-Mg concretions; about 5 percent by volume shale and sandstone fragments; extremely acid; abrupt irregular boundary. (0 to 12 inches thick.)
2Cr--59 to 75 inches; very dark gray and brown weakly cemented, fractured, acid shale containing less than 5 percent gray (10YR 6/1) clay between shale plates. Beds have dip of about 35 degrees from horizontal.
TYPE LOCATION: Hot Spring County, Arkansas; 1.4 miles west of De Roche School on Arkansas Highway 84; then north on gravel road 0.3 miles; then west 200 feet in the SE1/4NE1/4NW1/4, sec. 6, T. 5 S., R. 19 W.
RANGE OF CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. Depth to tilted shale ranges from 40 to more than 72 inches. Reaction ranges from extremely acid to strongly acid throughout except for surface layers where limed. Coarse fragment content ranges from 0 to 10 percent by volume in the A, BE, and Bt horizons.
The A horizon has hue of 10YR, value of 4 or 5 and chroma of 2 to 4. Texture is fine sandy loam or sandy loam. Mottles are in shades of brown.
The BE horizon has hue of 10YR, value of 5 and chroma of 4 to 8. Texture is fine sandy loam or sandy loam. Mottles are in shades of brown or gray.
The Bt horizon has hue of 10YR or 7.5YR value of 5 and chroma of 4 to 8 with mottles in shades of gray; or it is mottled horizon in shades of brown and gray. Texture is fine sandy loam, loam or sandy loam in the upper part, but ranges to sandy clay loam in the lower part. Subhorizons are brittle in 15 to 35 percent of the mass in most pedons.
The 2C horizon has hue of 10YR value of 5 or 6 and chroma of 1 or 2 and mottles in shades of brown or red; or it is mottled horizon in shades of gray, brown, and red. It is generally quite variable in short distances. Texture is loam, clay loam, silty clay or clay or with their gravelly or shaly analogs. Coarse fragments of shale and sandstone range from 0 to 30 percent.
The 2Cr horizon is gray, brown and red, soft, weakly cemented, acid shale with few thin strata of interbedded sandstone. Fine-earth material is less than 5 percent of the volume. Beds are fractured and dip ranges from 25 degrees to near vertical. Hardness of this material on Mohs' scale ranges from 1.5 to 3.0.
COMPETING SERIES: These include the Nansemond series in the same family and Munden, Hammonton, Altavista, Columbus, and Eunola series in similar families. Nansemond soils do not have a lithologic discontinuity within 72 inches of the soil surface. Munden soils are in a mixed mineralogy class. Hammonton soils, have mean annual soil temperatures of less than 59 degrees F. Altavista soils are in a mixed mineralogy class and are in a fine-loamy particle size class. Columbus and Eunola soils are in a fine-loamy particle size class.
GEOGRAPHIC SETTING: Bonnerdale soils are level to gently sloping slightly concave uplands in the Ouachita Mountains along the contact with the Western Coastal Plains. The soil formed in loamy sediments over soft tilted, interbedded shale and sandstone. Slope ranges from 0 to 8 percent, but is dominantly less than 5 percent. The mean annual temperature is about 62 degrees F and the annual precipitation is about 52 inches near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bismarck, Carnasaw, Pirum, and Sherless series. Bismarck soils, which are on valley floors and lower sideslopes, are in a loamy-skeletal particle size class and are less than 20 inches deep to soft interbedded shale and sandstone. Carnasaw soils, which are on sideslopes, are in a clayey particle size class and are better drained. Pirum soils, which are on ridges, are in a fine-loamy particle size class and are 22 to 50 inches deep over hard sandstone. Sherless soils, which are on ridges and sideslopes, are in a fine-loamy particle size class and are 20 to 40 inches deep over soft sandstone.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow to medium runoff; and moderate permeability. A seasonally high water table is within 6 inches of the soil surface from December through May.
USE AND VEGETATION: Most areas are in forest. Native trees are shortleaf pine, Loblolly pine and upland oaks. Small acreages have been cleared and used for pasture and hay.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
DISTRIBUTION AND EXTENT: Ouachita Mountains of Arkansas and possibly Oklahoma. The series is of moderate extent.
SERIES ESTABLISHED: Hot Spring County, Arkansas; 1982
REMARKS: Diagnostic feature and horizons recognized in this pedon:
Ochric epipedon - The zone from the surface to a depth of 5 inches.
Argillic horizon - The zone from 5 to 54 inches.
Paralithic contact - The zone from 59 to 75 inches.
ADDITIONAL DATA: Characterization on typical pedon by University of Arkansas Soil Characterization Laboratory. Pedon No. S81AR-059-3.