LOCATION TOLLFLAT SD+WY
Established Series
JWW
09/2011
TOLLFLAT SERIES
The Tollflat series consists of deep and very deep, well drained soils that formed in residuum derived from sandstone. Tollflat soils are on gently sloping to steep ridges and hillslopes on mountain flanks. Slopes range from 2 to 60 percent. The mean annual precipitation is about 610 mm and the mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Hapludalfs
TYPICAL PEDON: Tollflat loam, on an east facing, linear slope of 14 percent, in a mixed coniferous and deciduous woodland community at an elevation of 1,400 meters. (Colors are for moist soil unless otherwise noted.) When described on October 12, 2008 the soil was dry from 0 to 20 cm and slightly moist below.
Oi--0 to 2 cm; slightly decomposed pine needles and twigs, and herbaceous plant residue. (1 to 3 cm thick)
A--2 to 7 cm; very dark grayish brown (10YR 3/2) very fine sandy loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, common fine, and few medium roots; slightly acid; abrupt wavy boundary. (0 to 13 cm thick)
AE--7 to 20 cm; dark yellowish brown (10YR 4/4) very fine sandy loam, very pale brown (10YR 7/4) dry; weak fine and medium angular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; moderately acid; abrupt smooth boundary. (0 to 13 cm thick)
E--20 to 27 cm; brown (7.5YR 5/4) loamy very fine sand, pink (7.5YR 7/4) dry; moderate fine and medium angular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine and medium roots; moderately acid; clear wavy boundary. (6 to 18 cm thick)
Bt/E--27 to 34 cm; about 60 percent brown (7.5YR 4/4) clay loam, light brown (7.5YR 6/4) dry (Bt part) and 40 percent brown (7.5YR 5/4) very fine sandy loam, pink (7.5YR 7/4) dry (E part); strong fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine, fine and medium roots; common (40 percent) faint strong brown (7.5YR 4/6) clay films on faces of peds (Bt part); moderately acid; clear wavy boundary. (6 to 18 cm thick)
Bt1--34 to 50 cm; strong brown (7.5YR 4/6) clay loam, strong brown (7.5YR 5/6) dry; weak medium prismatic structure parting to strong fine and medium subangular blocky; moderately hard, firm, sticky and plastic; few very fine and fine roots; common (40 percent) faint strong brown (7.5YR 4/6) clay films on all faces of peds; slightly acid; clear wavy boundary.
Bt2--50 to 68 cm; strong brown (7.5YR 4/6) and strong brown (7.5YR 5/6) clay, strong brown (7.5YR 5/6) and reddish yellow (7.5YR 6/6) dry; strong medium and coarse subangular blocky structure; moderately hard, firm, sticky and very plastic; few very fine and fine roots; common (40 percent) faint brown (7.5YR 5/4) clay films on all faces of peds; slightly acid; clear wavy boundary.
Bt3--68 to 90 cm; 90 percent yellowish red (5YR 4/6), yellowish red (5YR 5/6) dry, 5 percent yellowish brown (10YR 5/6), brownish yellow (10YR 6/6) dry, and 5 percent red (2.5YR 4/8), red (2.5YR 5/8) dry clay; strong medium and coarse angular blocky structure; moderately hard, firm, sticky and plastic; few very fine roots; very few (3 percent) prominent very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) organic stains on faces of peds; common (30 percent) faint yellowish red (5YR 4/6) clay films on all faces of peds; slightly acid; clear wavy boundary. (Combined thickness of the Bt horizon is 30 to 85 cm)
Bt/C--90 to 106 cm; 75 percent strong brown (7.5YR 4/6), strong brown (7.5YR 5/6) dry (Bt part) and 20 percent dark yellowish brown (10YR 4/6), yellowish brown (10YR 5/6) dry, and 15 percent red (2.5YR 4/6), red (2.5YR 5/6) dry (C part) gravelly clay loam; moderate medium and coarse subangular blocky structure; moderately hard, friable, slightly sticky and moderately plastic; about 15 percent angular and subangular sandstone and limestone gravel, 10 percent cobble, and 5 percent stones; very few (3 percent) prominent very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) organic stains on faces of peds (Bt part); common (20 percent) prominent strong brown (7.5YR 4/6) clay films on vertical faces of peds (Bt part); calcium carbonate occurs as thin spheres, generally less than 5 mm thick, surrounding calcareous rock fragments (C part); neutral; abrupt wavy boundary. (0 to 26 cm thick)
Cr--106 to 152 cm; weakly to moderately cemented, noncalcareous sandstone.
TYPE LOCATION: Lawrence County, South Dakota; about 2 miles south of US Highway 14A and Boulder Canyon; about 2,430 feet south and 2,130 feet west of the northeast corner of Sec. 25, T.5N., R.4E.; Deadman Mountain USGS quad; 44 degrees 21 minutes 58 seconds N. latitude and 103 degrees 34 minutes 40.2 seconds W. longitude; NAD 83
RANGE IN CHARACTERISTICS:
Depth to argillic horizon: 15 to 38 cm
Thickness of the argillic horizon: 35 to 90 cm
Depth to secondary calcium carbonate: 75 to greater than 102 cm
Particle-size control section (weighted average):
Clay content: 35 to 45 percent
Sand content: 15 to 30 percent
Rock fragments: 0 to 15 percent angular and/or subangular sandstone and/or limestone gravel
A horizon:
Hue: 7.5YR or 10YR
Value: 2 or 3, 3 to 5 dry
Chroma: 1 or 2
Texture: Loam, fine sandy loam, very fine sandy loam
Reaction: slightly acid to strongly acid
An AE horizon occurs in some pedons. It has properties similar to the A and E horizons.
E horizon:
Hue: 5YR, 7.5YR, or 10YR
Value: 4 through 6, 5 through 7 dry
Chroma: 2 through 4
Texture: Loam, very fine sandy loam, fine sandy loam
Reaction: slightly acid to strongly acid
The Bt/E (or E/Bt) horizon has combined properties of the Bt and E horizons. It typically consists of 30 to 70 percent Bt horizon material and 30 to 70 percent E horizon material.
Bt horizon:
Hue: typically 2.5YR, 5YR, or 7.5YR; some pedons have irregular masses of weathered sandstone with hues of 10YR
Value: 4 or 5, 5 or 6 dry
Chroma: 4 through 8
Texture: CL, C
Clay content: 35 to 45 percent average; individual layers may contain up to 55 percent clay
Reaction: moderately acid to neutral
A Btk or Bk horizon is present in some pedons.
Bt/C horizon:
Hue: typically 2.5YR, 5YR, or 7.5YR; most pedons have irregular masses of weathered sandstone with hues of 10YR
Value: 4 or 5, 5 or 6 dry
Chroma: 3 through 6
Texture: CL, C (fine-earth fraction)
Clay content: 30 to 45 percent
Rock fragments: angular and subangular, sandstone and/or limestone gravel, as follows: 10 to 30 percent gravel, 0 to 15 percent cobble, and 0 to 10 percent stones
Reaction: neutral or mildly alkaline
Cr horizon:
Bedrock characteristics: weakly to moderately cemented, brownish yellow (10YR 5/6) to light red (2.5YR 6/8) noncalcareous sandstone or interbedded sandstone and limestone.
COMPETING SERIES:
Porthill - formed in calcareous silty and clayey glacio-lacustrine sediments; hues are 10YR or yellower
GEOGRAPHIC SETTING:
Parent material: Residuum or colluvium derived from medium to fine grained, sandstone, or interbedded sandstone and limestone
Landform: ridges and hillslopes on mountain flanks
Slopes: 2 to 60 percent
Elevation: 1,370 to 1,890 meters
Mean annual air temperature: 5 to 8 degrees C
Mean annual precipitation: 510 to 710 mm
Precipitation pattern: In most years, half or more of the annual precipitation occurs as snow and rain from March through July.
Frost-free period: 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
Citadel - have less than 15 percent fine and coarser sand in the control section; on similar or slightly lower landscape positions
Hickok(T) - are fine-loamy; on similar landscape positions
McCooley(T) - are sandy and have lamella instead of contiguous Bt horizons; on similar or slightly higher landscape positions
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately low saturated hydraulic conductivity
USE AND VEGETATION: Tollflat soils are used for timber production, wildlife habitat, recreation, and livestock grazing. Native vegetation consists of an overstory of ponderosa pine, aspen, and bur oak; understory species consist of roughleaf ricegrass, timber oatgrass, Columbia needlegrass, Oregon grape, bearberry, and common juniper.
DISTRIBUTION AND EXTENT: Tollflat soils occur on the Low Limestone Plateau physiographic area in the Black Hills of South Dakota and Wyoming; LRR G, MLRA 62; the series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES PROPOSED: Update of the Soil Survey of Lawrence County, South Dakota, 2006.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 27 to 77 cm (Bt/E, Bt1, Bt2, and the upper part of the Bt3 horizons)
Ochric epipedon: The zone from 2 to 27 cm (A, AE, and E horizons)
Argillic horizon: The zone from 27 to 106 cm (Bt/E, Bt1, Bt2, Bt3, and Bt/C horizons)
E horizons typically have chroma too high to classify as albic
The Tollflat series replaces the Larkson series mapped in the Black Hills parts of Crook County, Wyoming.
Series mineralogy is inferred from laboratory analysis of similar soils with the same geomorphology.
Taxonomic Version: Keys to Soil Taxonomy, Eleventh Ed., 2006
ADDITIONAL DATA:
National Cooperative Soil Survey
U.S.A.