LOCATION HARPERSVILLE TXEstablished Series
The Harpersville Series consist of well drained, very slowly permeable, very shallow or shallow soils over claystone bedrock or dense clay they formed in residuum from claystone bedrock. These soils are on strongly sloping to very steep erosionalescarpments. Slopes range from 5 to 45 percent.
TAXONOMIC CLASS: Clayey, mixed, active, calcareous, thermic, shallow Aridic Ustorthents
TYPICAL PEDON: Harpersville clay, very stony--on 12 percent slope, in rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 7 inches; light gray (5Y 7/2) clay, olive gray (5Y 5/2) moist; moderate fine and medium angular blocky structure; very hard, firm, very sticky and plastic; common fine and few medium roots; few fine pores; about 5 percent sandstone fragments in the form of flagstones, stones, and boulders are on the soil and in the surface layer; few seams of olive gray claystone in lower 2 inches; strongly effervescent; moderately alkaline; clear smooth boundary. (3 to 12 inches thick)
Cd1--7 to 15 inches; light olive gray (5Y 6/2) noncemented claystone bedrock, olive gray (5Y 4/2) moist; massive; coarsely fractured claystone parting into fine plates; extremely hard, extremely firm; few roots in crevices; few films and threads of calcium carbonate along crevices; ped interiors are noneffervescent ped exteriors are slightly effervescent; moderately alkaline; abrupt wavy boundary. (0 to 10 inches thick)
Cd2--15 to 60 inches; light olive gray (5Y 6/2) noncemented claystone bedrock, olive gray (5Y 4/2) moist; massive; claystone parting to coarse and medium plates; extremely hard, extremely firm; noneffervescent; moderately alkaline.
TYPE LOCATION: Stephens County, Texas: from U.S. 180 east of Breckenridge, 10.8 miles northeast on TX 67, then 2.3 miles south on FM 717, then 0.7 miles southwest on a county road, then 550 feet east in range. Latitude 32 degrees 49 feet 35 inches N; longitude 98 degrees 44 feet l8 inches W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 3 to 14 inches over densic material and 10 to 30 inches to a densic contact. PH is slightly alkaline or moderately akaline throughout. Calcium
The A horizon has hue of 7.5YR through 5Y, value of 3 through 7, and chroma of 2 through 6. Texture is clay, clay loam or silty clay. Flattened sandstone and limestone fragments range from 3 to 60 inches across cover from 1 to 15 percent of the soil surface. Most are lying flat but occasionally are embedded at a low angle. Calcium carbonate equivalent is 3 to 10 percent
The Cd horizon is in shades of olive, brown, yellow and gray, which are derived from the underlying sediments. These colors in many places are intermingled as strata, pockets or small discrete masses. This horizon is dense non cemented claystone bedrock or dense clay that is massive. Most of these fragments slake in water in a few seconds or less than one hour. These materials can be excavated by a backhoe. Gypsum in the form of soft crystals, granules or thin horizontal strata occurs in some pedons. A few carbonates occur in fractures in the upper few inches in some pedons. Calcium carbonate equivalent is 0 to 5 percent.
COMPETING SERIES: This is similar to the Knoco series. Other similar soils are the Burson, Cottonwood, Owens and Vernon series. Knoco soils are redder and dryer, having hue of 5YR or redder. Burson and Cottonwood soils have less than 35 percent clay in the particle size control section, and in addition, Cottonwood soils are over gypsum and the Burson soils are over sandstone. Owens and Vernon soils have cambic horizons and solum development more than 12 inches thick.
GEOGRAPHIC SETTING: Harpersville soils are on narrow erosional escarpments. Slopes range from 5 to 45 percent. The soil formed in residuum over claystone bedrock of the Pennsylvanian System and the Wichita-Albany Group of the Permian System, both of which have some interbedded sandstone and limestone. Elevation at the type location is about 1,150 feet, or 350 meters. Mean annual precipitation is 24 to 30 inches, mean annual temperature is 63 to 65 degrees F. Frost free period is 220 to 230 days, and elevation ranges from 1,000 to 2,350 feet. Thornthwaite P-E indices ranges from 34 to 40.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Owens soils and the Bluegrove, Bonti, Exray, Palopinto, Throck and Thurber Series. The Owens soils are on adjacent generally less sloping areas. Bluegrove and Bonti soils have clayey argillic horizon and are mainly above on ridgetops. Exray soils have reddish argillic horizons and are less than 20 inches thick over sandstone and are above on ridges. Palopinto soils have mollic epipedons, have loamy-skeletal control sections, and are above on ridgetops. Throck soils have thicker sola and are adjacent or on lower positions. Thurber soils have an argillic horizon and are in valleys below.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. Runoff is very high.
USE AND VEGETATION: Mainly used for rangeland. The native vegetation is a sparse cover of sideoats grama, silver bluestem, purple threeawn, Arizona cottontop, catclaw acacia, agarita, lotebush and ephedra.
DISTRIBUTION AND EXTENT: North-Central Prairies(MLRA 80B) and Rolling Limestone Praries(MLRA 78D) of Texas. Harpersville soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Shackelford County, Texas; 1985.
REMARKS: This soil was previously included in the Owens and Knoco series. It was reclassified from Ustic Torriorthents to Aridic Ustorthents.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches. (A horizon)
Reaction - the soil is generally calcareous to the surface.
Densic material - 7 to 60 inches. (Cd layers)
Densic Contact - at 15 inches. (Top of Cd2 layer)