LOCATION TADPOLE ID

Established Series
Rev. ALH/RWL
07/2012

TADPOLE SERIES

The Tadpole series consists of very deep, well drained soils with moderate permeability that formed in loess and weathered volcanic ash over coarse-loamy alluvium from basalt and volcanic ash. Slopes range from 0 to 20 percent on plains. The average annual precipitation is about 7 inches and the average annual temperature is about 53 degrees F.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Durinodic Haplocalcids

TYPICAL PEDON: Tadpole silt loam -- on a nearly level lava flow trough, at 2,950 feet elevation in rangeland. When described on November 3, 1999, the soil was dry throughout. (Colors are for air-dry soil unless otherwise noted.)

A1--0 to 2 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; strong fine platy structure parting to moderate fine granular; soft, very friable, nonsticky and nonplastic; many very fine and fine, few medium roots; many very fine and fine irregular and tubular pores; neutral (pH 7.1); abrupt smooth boundary.

A2--2 to 5 inches; very pale brown (10YR 7/3) silt loam, brown (10YR 5/3) moist; moderate fine and medium platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine, few medium roots; many very fine and fine, few medium irregular and tubular pores; neutral (pH 7.3); clear smooth boundary. (combined A horizon - 2 to 10 inches thick)

Bw--5 to 12 inches; very pale brown (10YR 7/3) silt loam, brown (10YR 5/3) moist; moderate fine and medium subangular structure; slightly hard, very friable, slightly sticky and nonplastic; few very fine, fine and medium roots; common very fine and fine, few medium tubular pores; slightly alkaline (pH 7.8); clear smooth boundary. ( 0 to 7 inches thick)

Bk--12 to 18 inches; very pale brown (10YR 7/3) silt loam, pale brown (10YR 6/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; strongly effervescent (about 15 percent CaC03); calcium carbonate is disseminated throughout the peds; moderately alkaline (pH 8.0); clear smooth boundary. ( 3 to 24 inches thick)

Bkq--18 to 38 inches; very pale brown (10YR 7/3) silt loam, light yellowish brown (10YR 6/4) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 40 percent strongly cemented durinodes; violently effervescent (about 25 percent CaC03); calcium carbonate is disseminated throughout the peds; moderately alkaline (pH 8.0); clear smooth boundary. (12 to 24 inches thick)

2C--38 to 60 inches; pale brown (10YR 6/3) loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; violently effervescent (about 20 percent CaC03); calcium carbonate is disseminated; moderately alkaline (pH 7.9).

TYPE LOCATION: Elmore County, Idaho; about 8 miles northeast of Grandview; 150 feet south and 1500 feet west of the northeast corner of section 21, T.4 S., R.4 E.; USGS Crater Rings SW Quadrangle; (Latitude - 43 degrees, 04 minutes, 13 seconds N. and Longitude - 115 degrees, 58 minutes, 57 seconds W.).

RANGE IN CHARACTERISTICS:
Average annual soil temperature - 53 to 56 degrees F.
Depth to calcium carbonate - 2 to 14 inches
Depth to durinodes - 10 to 36 inches
Depth to lithologic discontinuity - 30 to 48 inches
Depth to bedrock - more than 60 inches
Particle-size control section - 8 to 18 percent clay; 0 to 5 percent rock fragments
Volcanic glass content - 5 to 15 percent
Alox + 1/2 Feox content - less than 0.2 percent
Moisture control section - dry for more than 180 days when the soil temperature is greater than 41 degrees F.

A horizon
Value - 5 or 6 dry, 3 or 4 moist
Clay content - 7 to 15 percent
Rock fragments - 0 to 5 percent gravel
Calcium carbonate content - 0 to 10 percent
Reaction - neutral or moderately alkaline

Bk horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Clay content - 10 to 18 percent
Rock fragments - 0 to 5 percent gravel
Calcium carbonate content - 10 to 20 percent
Reaction - slightly alkaline or moderately alkaline

Bkq horizon
Value - 6 or 7 dry, 5 or 6 moist
Chroma - 3 or 4 dry or moist
Clay content - 7 to 15 percent
Rock fragments - 0 to 5 percent gravel
Calcium carbonate content - 15 to 30 percent
Durinode content - 20 to 50 percent
Reaction - slightly alkaline or moderately alkaline

Some pedons have Bknq horizons similar to above, but have slight or moderate salinity with an EC of 4 to 16 dS/m.

2C horizon
Value - 6 or 7 dry, 5 or 6 moist
Chroma - 3 or 4 dry or moist
Texture - L, FSL or LFS
Clay content - 4 to 10 percent
Rock fragments - 0 to 15 percent gravel
Calcium carbonate content - 10 to 30 percent
Reaction - slightly alkaline or moderately alkaline
Salinity - very slight through moderate

Some pedons have buried thin layers with continuous silica cementation below 40 inches

COMPETING SERIES: There are no competing series. The Chijer and Portneuf soils are similar, but both have a soil moisture regime that borders on xeric.

GEOGRAPHIC SETTING: Tadpole soils are on plug domes, pressure ridges, lava flow lobes and troughs on shield volcanoes of plains. Elevations are 2,800 to 3,550 feet. Slopes range from 0 to 20 percent. These soils formed in loess and weathered volcanic ash over coarse-loamy alluvium from basalt and volcanic ash. Average annual precipitation is 6 to 8 inches. Average annual temperature is 51 to 54 degrees F. Frost-free period is 130 to 160 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Laped, Purdam, Scism, Trevino and Weso soils. Purdam, Scism and Trevino soils have a soil moisture regime that borders on xeric. Laped and Trevino soils are less than 20 inches deep. Weso soils have a coarse-loamy particle-size control section. Landscape positions are similar.

DRAINAGE AND PERMEABILITY: Well drained; very slow to medium runoff; moderate permeability.

USE AND VEGETATION: Tadpole soils are used mainly for rangeland. Natural vegetation is shadscale saltbush, bud sagebrush, Indian ricegrass, Thurber needlegrass and on saline areas winterfat.

DISTRIBUTION AND EXTENT: Ada and Elmore Counties, Idaho; MLRA 11. These soils are of limited extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Ada County Idaho, 2012.

REMARKS: Diagnostic horizons and features recognized in this pedon:

Ochric epipedon - zone from the surface to 5 inches (A1 and A2 horizons)

Cambic horizon - zone from 5 to 12 inches (Bw horizon)

Calcic horizon - zone from 12 to 38 inches (Bk and Bkq horizons)

Particle-size control section - zone from 10 to 40 inches

Soil moisture regime - aridic

More investigation of the chemical characteristics of the saline phase of this series is needed to determine what relationship the higher EC values have to the winterfat plant community.

ADDITIONAL DATA: Reference sample no. - S99ID-001-003 (NSSL Pedon 0P 208)

National Cooperative Soil Survey
U.S.A.