LOCATION STEPROCK AR+OK
Established Series
JP AN/Rev.MDJ
04/2016
STEPROCK SERIES
TAXONOMIC CLASS: Loamy-skeletal, siliceous, subactive, thermic Typic Hapludults
TYPICAL PEDON: Steprock very flaggy loam, 16 percent slopes in woodland. (Colors are for moist soil unless otherwise stated.)
Oi--0 to 3 cm (0 to 1 inches); partly decomposed organic matter.
A--3 to 6 cm (1 to 2 inch); dark grayish brown (10YR 4/2) very flaggy loam; weak fine granular structure; very friable; few fine roots; about 20 percent by volume gravel 2 to 75 mm in diameter and 20 percent by volume flat fragments of sandstone 75 to 250 mm in diameter; strongly acid; abrupt smooth boundary. (0 to 8 cm thick (0 to 3 inches))
E--6 to 11 cm (2 to 4 inches); brown (10YR 5/3) very flaggy loam; weak fine subangular blocky structure; friable; few fine roots; few fine pores; about 20 percent by volume gravel 2 to 75 mm in diameter and 20 percent by volume flat fragments of sandstone 75 to 250 mm in diameter; strongly acid; clear smooth boundary. (5 to 15 cm thick (2 to 6 inches))
BE--11 to 26 cm (4 to 10 inches); yellowish brown (10YR 5/8) very flaggy fine sandy loam; weak medium subangular blocky structure; friable; many fine and medium roots; common fine pores; about 20 percent by volume gravel 2 to 75 mm in diameter and 20 percent by volume flat fragments of sandstone 75 to 250 mm in diameter; very strongly acid; clear smooth boundary. (0 to 20 cm thick (0 to 8 inches thick))
Bt1--26 to 44 cm (10 to 17 inches); strong brown (7.5YR 5/8) very gravelly loam; weak fine and medium subangular blocky structure; friable; many fine and medium roots; common medium pores; few thin patchy clay films; about 20 percent by volume gravel 2 to 75 mm in diameter and about 15 percent by volume flat fragments of sandstone 75 to 250 mm in diameter; very strongly acid; clear wavy boundary.
Bt2--44 to 64 cm (17 to 25 inches); yellowish red (5YR 5/8) very gravelly loam; moderate fine and medium subangular blocky structure; friable; common fine and medium roots; few medium pores; many thin patchy clay films on faces of peds and in pores; about 35 percent by volume gravel 2 to 75 mm in diameter and about 20 percent by volume flat fragments of sandstone 75 to 380 mm in diameter; few medium distinct strong brown (7.5YR 5/6) mottles in matrix; very strongly acid; gradual wavy boundary.
Bt3--64 to 74 cm (25 to 29 inches); yellowish red (5YR 5/8) extremely gravelly loam; weak fine subangular blocky structure; very friable; few fine roots; about 75 percent by volume weathered fragments of sandstone 2 to 250 mm in diameter; few thin vertical streaks of loamy sand coated with thin clay films; very strongly acid; clear irregular boundary. (Combined thickness of the Bt horizons is 33 to 63 cm (13 to 25 inches))
Cr--74 to 125 cm (29 to 49 inches); yellowish red (5YR 5/8) weathered sandstone bedrock with thin vertical interstices filled with sand.
TYPE LOCATION:
County: White
State: Arkansas
USGS Quadrangle: Floyd, Arkansas
Latitude (Decimal Degrees, NAD 83): 35.2015
Longitude (Decimal Degrees, NAD 83): -91.9894
Directions to the pedon: 1.9 miles west on county road from Ark. Hwy., 31 at Floyd in NE1/4SE1/4SW1/4 sec. 29, T. 7 N., R 9 W.
RANGE IN CHARACTERISTICS:
Depth to the top of the Argillic: 5 to 43 cm (2 to 17 inches)
Depth to the bottom of the Argillic: 33 to 74 cm (13 to 29 inches)
Depth to Paralithic Contact: 51 to 102 cm (20 to 40 inches)
Solum Thickness: 51 to 102 cm (20 to 40 inches)
Depth to bedrock: 51 to 102 cm (20 to 40 inches)
Depth Class: Moderately Deep
Rock Fragment content: 5 to 60 percent, by volume in the A, E, BE horizons; 35 to 75 percent, by volume, in the Bt horizon
Soil Reaction: strongly acid or very strongly acid except where surface layers are limed
Range of Individual Horizons
A Horizon
Color: hue of 10YR, value of 3 to 5, and chroma of 2 or 3
Texture: sandy loam, loam, silt loam, or fine sandy loam
Fragments: 5 to 60 percent fragments; gravelly, very gravelly, very flaggy, stony, and very stony
E Horizon
Color: hue of 10YR, value of 5 or 6, and chroma of 3 or 4
Texture: sandy loam, loam, silt loam, or fine sandy loam
Fragments: 5 to 60 percent fragments; gravelly, very gravelly, very flaggy, stony, and very stony
BE Horizon (if it occurs)
Color: hue of 10YR, 7.5YR, or 5YR, value of 5 and chroma of 6 or 8
Texture: sandy loam, fine sandy loam, loam
Fragments: 5 to 60 percent fragments; gravelly, very gravelly, very flaggy, stony, and very stony
Bt Horizon
Color: hue of 7.5YR, 5YR, or 2.5YR, value of 4 or 5, and chroma of 6 or 8
Texture: sandy clay loam, clay loam, silt loam, or loam
Fragments: 35 to 75 percent fragments; very gravelly, very flaggy, extremely gravelly, and extremely flaggy
Mottles (if they occur): few red and brown mottles
BC Horizon (if it occurs)
Color: hue of 5YR or 2.5YR, value of 4 or 5, and chroma of 6 or 8
Texture: sandy loam, fine sandy loam, loamy fine sand, loamy sand, and silt loam
Fragments: 35 to 60 percent fragments; very gravelly or very flaggy
C Horizon (if it occurs)
Textures: sandy loam, fine sandy loam, loamy fine sand, loamy sand, sand, or silt loam
Fragments: 35 to 60 percent fragments; very gravelly or very flaggy
Cr Horizon
Material: partly weathered sandstone, siltstone, shale, or interbedded layers of these materials
Hardness: extremely weakly to moderately cemented
COMPETING SERIES:
Bigfork soils: are underlain by hard chert and tilted 20 degrees to 60 degrees from the horizontal.
Lillington soils: have sola more than 60 inches thick.
Saffell and
Subligna soils: lack bedrock within 60 inches.
Zafra soils: are underlain with interbedded sandstone and lenses of shale tilted at 20 degrees to 60 degrees from the horizontal
GEOGRAPHIC SETTING:
Landscape: hills
Landform: ridges and hillslopes
MLRA(s): 117 and 118
Hillslope Profile Position: sideslope
Parent Material: loamy residuum or residuum and colluvium weathered from sandstone, siltstone, and shale of the Atoka formation or similar acid low base bedrock
Slope: 3 to 60 percent
Mean Annual Air Temperature: 15.6 to 17.2 degrees C (60 to 63 degrees F)
Mean Annual Precipitation: 1143 to 1270 mm ( 45 to 50 inches)
GEOGRAPHICALLY ASSOCIATED SOILS:
Enders soils: have more than 35 percent clay and less than 35 percent coarse fragments in the upper 20 inches of the argillic horizon and are at lower elevations
Leesburg soils: have less than 35 percent coarse fragments in the upper 20 inches of the argillic horizon and are on slightly lower sideslopes
Leadvale soils: have a fragipan and are on lower lying sideslopes, valley fill and terraces
Linker soils: underlain by hard sandstone and are on nearby plateaus and benches
Mountainburg soils: shallow to hard sandstone and are on higher ridgetops or adjacent benches
Nella soils: have less than 35 percent coarse fragments in the upper 20 inches of the argillic horizon and are on slightly lower sideslopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage Class: Well
Index Surface Runoff: medium or rapid
Saturated Hydraulic Conductivity Class: Moderate
Permeability Class (Obsolete): moderate
Flooding Frequency and Duration: none
Ponding frequency and Duration: none
USE AND VEGETATION:
Major uses: pasture, forest, some cultivated row crops
Dominant vegetation: Forests are blackjack, post, red and white oak, blackgum, hickory, and shortleaf pine
DISTRIBUTION AND EXTENT:
Distribution: Boston Mountains, Arkansas Valley and Ridges of Arkansas and Oklahoma
Extent: moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: White County, Arkansas; 1980.
REMARKS:
Steprock soils were formerly included with the Linker series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--surface to a depth of 26 cm (10 inches) (A, E, BE horizons)
Argillic horizon--depth between 26 and 74 cm (9 and 28 inches) (Bt horizons)
Paralithic contact 74 and 125 cm (28 to 48 inches) (Cr horizon)
ADDITIONAL DATA:
Lab data from the University of Arkansas is available for the following pedons:
S99AR131-02-1, S99AR131-10-1, S82AR141-08-1, S79AR145-09-1
________________________________________
National Cooperative Soil Survey
U.S.A.