LOCATION PIGTAIL IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Abruptic Xeric Argidurids
TYPICAL PEDON: Pigtail silt loam--on a slope of 2 percent under rangeland vegetation at 5,300 feet elevation. When described on September 22, 1982, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise stated.)
A1--0 to 3 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate coarse platy structure; hard, friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine tubular pores; neutral (pH 6.9); abrupt smooth boundary. (1 to 4 inches thick)
A2--3 to 7 inches; pale brown (10YR 6/3) silty clay loam, dark brown (10YR 3/3) moist; moderate medium platy structure; hard, friable, sticky and plastic; many very fine to medium roots; many very fine tubular pores; neutral (pH 6.9); abrupt smooth boundary. (2 to 4 inches thick)
Bt--7 to 18 inches; pale brown (10YR 6/3) silty clay, brown (10YR 4/3) moist; strong coarse prismatic structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; many prominent clay films on faces of peds and in pores; neutral (pH 7.3); abrupt wavy boundary. (8 to 22 inches thick)
Bkq--18 to 32 inches; very pale brown (10YR 8/3) loam, pale brown (10YR 6/3) moist; massive; very hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 5 percent gravel; violently effervescent (18 percent calcium carbonate); moderately alkaline (pH 7.9); abrupt smooth boundary. (9 to 25 inches thick)
Bkqm--32 to 60 inches; white (10YR 8/1) fractured duripan, very pale brown (10YR 7/3) moist; platy; indurated; extremely hard, extremely firm; many 1/2 inch to 3 inch thick lime-silica cemented laminations with sandy loam soil material between the laminations; few very fine roots in fractures of the duripan; fractures are 1/4 inch wide and are 8 inches apart; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Twin Falls County, Idaho; about 20 miles west of Rogerson, Idaho; in the northeast 1/4, northwest 1/4, northeast 1/4, section 6, T. 14 S., R. 13 E.
RANGE IN CHARACTERISTICS:
Depth to the duripan - 20 to 40 inches
Depth to bedrock - more than 60 inches
Clay content in the control section - 45 to 55 percent
Average annual soil temperature - 47 to 50 degrees F.
A1 horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 or 3 dry or moist
Bt horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 through 4 dry or moist
Prismatic or angular blocky structure
Clay content - 45 to 55 percent
Bkqm horizon
Thickness of laminar capping - 1/2 to 3 1/2 inches
Massive or platy structure
Weak through strong cementation below capping
Width of fractures - 1/4 to 1/2 inch
Distance between fractures - 7 to 20 inches
Thickness of duripan - 21 to more than 40 inches
Thickness of subsequent laminations - 1 to 6 inches
COMPETING SERIES: These are the Catchell, Chilcott, Kepler, Lookout, Lovejoy, and Reno series. Catchell soils are underlain by bedrock at a depth of less than 40 inches. Chilcott soils have E horizons with silt loam or very fine sandy loam textures directly over the abrupt textural change and a duriapn with laminations of very strong or indurated plates less than 20 inches thick. Kepler and Reno soils have duripans less than 20 inches thick. Lookout soils have more than 5 percent rock fragments in the control section. Lovejoy soils have 35 to 45 percent clay in the Bt horizon.
GEOGRAPHIC SETTING: Pigtail soils are in depressions on terraces. The slope ranges from 1 to 3 percent. The soils formed in alluvium from mixed sources. Elevations are 4,600 to 5,500 feet. The average annual precipitation ranges from 9 to 12 inches. The average annual temperature is 46 to 48 degrees F. The frost free season is 100 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elijah, Roseworth, and Tanner soils. Elijah, Roseworth, and Tanner soils occur on higher terraces. Elijah soils are fine-silty. Roseworth soils are shallow to a hardpan. Tanner soils are frigid.
DRAINAGE AND PERMEABILITY: Well drained, slow runoff; very slow permeability.
USE AND VEGETATION: Pigtail soils are used for rangeland. Native vegetation is stunted Wyoming big sagebrush, Thurber needlegrass, Sandberg bluegrass, and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Pigtail soils are of small extent in south central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.
REMARKS: Percent clay by hydrometer: 0-3 inches - 16 percent; 3-7 inches - 28 percent; 7-18 inches - 45 percent.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (A1 and A2 horizons)
Abrupt textural change - 7-8 inches (boundary between A2 and Bt horizons)
Argillic horizon - 7 to 18 inches (Bt horizon)
Calcic horizon - 18 to 32 inches (Bkq horizon)
Duripan - 32 to 60 inches (Bkqm horizon)
The classification of this pedon has been revised as of 4/00 from Abruptic Xerollic Durargids to Abruptic Xeric Argidurids based on revisions to Soil Taxonomy.