LOCATION CITIVAR SD+WY
Tentative Series
JWW/DJB
05/2011
CITIVAR SERIES
The Citivar series consists of deep and very deep, well drained soils that formed in residuum and local alluvium or colluvium over residuum derived from red silty calcareous shale. Citivar soils are on backslopes and footslopes of hillslopes on mountains. Slopes range from 6 to 40 percent. Mean annual precipitation is about 584 mm and the mean annual temperature is about 8 degrees C.
TAXONOMIC CLASS: Clayey over fragmental, mixed, superactive, frigid Udic Haplustalfs
TYPICAL PEDON: Citivar silt loam, on a south facing, convex hillslope of 26 percent in a mixed coniferous/deciduous woodland and grassland community at an elevation of 1,356 meters. (Colors are for moist soil unless otherwise noted.) When described on October 26, 2005 the soil was slightly moist throughout.
Oi--0 to 1 cm; slightly decomposed bur oak leaves, herbaceous plant leaves and stems, and a few scattered pine needles. (0 to 2.5 cm thick)
A--1 to 5 cm; dark reddish brown (5YR 3/2) silt loam, reddish brown (5YR 4/3) dry; weak fine granular structure; soft, friable, nonsticky and slightly plastic; many very fine, common fine roots throughout; many very fine, common fine continuous tubular pores; slightly acid; abrupt wavy boundary. (0 to 10 cm thick)
E--5 to 13 cm; reddish brown (5YR 4/3) silt loam, reddish brown (5YR 5/4) dry; weak fine platy structure parting to moderate fine subangular blocky; slightly hard, friable, nonsticky and slightly plastic; many very fine, common fine roots throughout; many very fine, common fine continuous tubular pores; moderately acid; clear wavy boundary. (5 to 15 cm thick)
Bt--13 to 37 cm; reddish brown (2.5YR 4/4) silty clay, red (2.5YR 5/6) dry; weak medium and strong fine angular blocky structure; hard, firm, sticky and moderately plastic; many very fine, common fine, and few medium roots throughout; common very fine, few fine continuous tubular pores; many (about 75 percent) distinct reddish brown (2.5YR 4/4) dry clay films on all faces of peds and few (about 20 percent) distinct reddish brown (2.5YR 4/3) dry organic stains on all faces of peds; 10 percent angular, weakly cemented shale parachanners;slightly acid; clear irregular boundary. (20 to 50 cm thick)
Btk--37 to 57 cm; red (2.5YR 4/6) parachannery silty clay, red (2.5YR 5/6) dry; weak fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine, common fine, and few medium roots throughout; few fine and very fine, discontinuous tubular pores; few (about 20 percent) distinct reddish brown (2.5YR 4/4) dry clay films on all faces of peds; 15 percent angular, weakly to moderately cemented shale parachanners, and 5 percent angular, strongly cemented shale channers; calcium carbonate disseminated throughout; slightly effervescent; slightly alkaline; gradual irregular boundary. (0 to 25 cm thick)
BCk--57 to 74 cm; red (2.5YR 4/6) channery silty clay loam, red (2.5YR 5/6) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine, few medium and fine roots throughout; very few fine pores; 15 percent angular, strongly cemented shale channers and 60 percent angular, weakly to moderately cemented shale parachanners; common coarse and very coarse prominent pinkish white (7.5YR 8/2) dry irregularly shaped carbonate masses around rock fragments; strongly effervescent; moderately alkaline; gradual wavy boundary. (13 to 38 cm thick)
2C--74 to 142 cm; reddish brown (2.5YR 5/4), red (2.5YR 5/6) and light red (2.5YR 6/6) moderately to very strongly cemented silty shale; common to many fine and very fine roots are matted on top of the horizon and few fine and very fine roots occur between fractures; less than 5 percent silt loam and silty clay loam material between fragments; distance between fractures is about 2 to 10 centimeters in the upper part of the horizon and greater than 10 centimeters in the lower part; strongly effervescent in the upper part and slightly effervescent in the lower part; moderately alkaline; gradual irregular boundary. (46 to 78 cm thick)
2Cr--142 to 203 cm (56 to 80 inches); reddish brown (2.5YR 5/4), light reddish brown (2.5YR 6/4) and light red (2.5YR 6/6) moderately to strongly cemented silty shale.
TYPE LOCATION: Lawrence County, South Dakota; about .5 mile southeast of Spearfish, SD; about 165 feet north and 1,180 feet west of the southeast corner of Sec. 21, T. 6 N., R. 2 E.; Spearfish USGS quad; 44 degrees 27 minutes 37.8 seconds N. latitude and 103 degrees 52 minutes 25.8 seconds W. longitude; NAD 83.
RANGE IN CHARACTERISTICS:
Depth to fragmental material: 50 to 100 cm
Particle-size control section (weighted average):
Clay content: 35 to 45 percent
Rock fragments: 0 to 15 percent strongly or very strongly cemented, angular shale channers; 5 to 35 percent very weakly to moderately cemented, angular shale parachanners in the upper part and over 90 percent in the lower part.
An Oi or Oe horizon occurs in most pedons
A horizon:
Hue: 5YR or 7.5YR
Value: 2 or 3 moist, 3 to 5 dry
Chroma: 2 or 3
Texture: SIL, L
Reaction: moderately acid to neutral
E horizon:
Hue: 2.5YR, 5YR, or 7.5YR
Value: 4 or 5 moist, 5 or 6 dry
Chroma: 2 to 4
Texture: SIL, L
Reaction: moderately acid to neutral
Bt horizon:
Hue: 2.5YR or 5YR
Value: 3 to 5 moist, 5 or 6 dry
Chroma: 3 to 6
Texture: SICL, CL, SIC
Reaction: slightly acid to slightly alkaline
Btk horizon (when present):
Hue: 10R, 2.5YR, or 5YR
Value: 4 or 5 moist, 5 or 6 dry
Chroma: 3 to 6
Texture: SICL, CL, SIC, PCN-SICL, PCN-SIC
Reaction: neutral or slightly alkaline
BCk (or Bk) horizon:
Hue: 10R, 2.5YR, or 5YR
Value: 4 or 5 moist, 5 or 6 dry
Chroma: 3 to 6
Texture (fine-earth fraction): SICL, CL, SIC
Rock fragments: 10 to 30 percent strongly or very strongly cemented, angular shale channers
Pararock fragments: 30 to 70 percent weakly to moderately cemented, angular shale channers
Calcium carbonate equivalent: 5 to 15 percent
Reaction: slightly alkaline or moderately alkaline
2C horizon:
Hue: 10R, 2.5YR, or 5YR
Value: 5 to 7 moist or dry
Chroma: 3 to 6
2Cr horizon:
Hue: 10R, 2.5YR, or 5YR
Value: 5 to 7 moist or dry
Chroma: 3 to 6
COMPETING SERIES: There are no competing series in this taxonomic class.
GEOGRAPHIC SETTING:
Parent material: Residuum, or local slope alluvium or colluvium over residuum, derived from red silty calcareous shale of the Opeche formation.
Landform: Hillslope positions in mountains, including backslopes and footslopes
Slopes: 6 to 40 percent
Elevation: 1,220 to 1,470 meters
Mean annual air temperature: 6.5 to 8 degrees C
Mean annual precipitation: 508 to 635 millimeters
GEOGRAPHICALLY ASSOCIATED SOILS:
Opechekahta(T) - lack argillic horizons and contain less clay; they generally occur above the Citivar soils
Rockerville - shallow to hard limestone; they occur on ridges above Citivar soils
Schaeferville(T) - are moderately deep over soft red shale and are fine-silty; they occur on similar landscape positions as Citivar
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to very high runoff; moderately slow to slow saturated hydraulic conductivity.
USE AND VEGETATION: Citivar soils are in an interspersed woodland/grassland vegetative community. They are utilized for livestock grazing, wildlife habitat, and limited timber production. The native vegetation consists of an overstory of ponderosa pine and bur oak; understory species include slender wheatgrass, bearded wheatgrass, sideoats grama, blue and/or hairy grama, little bluestem, big bluestem, and western snowberry.
DISTRIBUTION AND EXTENT: Citivar soils occur on the Low Limestone Plateau physiographic area of 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: Extensive revision of the Soil Survey of Lawrence County, South Dakota, 2007. The name is a coined version of the established series Citadel.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 1 to 13 cm (A and E horizons)
Argillic horizon: The zone from 13 to 57 cm (Bt and Btk horizons)
Fragmental material: The zone from 74 to 142 cm(2C horizon)
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area. The assignment of soil mineralogy class is assumed and is tentative pending sampling and laboratory analysis of typical pedon.
Taxonomic Version: Keys to Soil Taxonomy, Eleventh Ed., 2010
National Cooperative Soil Survey
U.S.A.