LOCATION ST. ANTHONY        ID+WY

Established Series
Rev. RG/CBR/FCF
08/2008

ST. ANTHONY SERIES

The St. Anthony series consists of very deep, well drained soils that formed in gravelly alluvium from mixed sources. St. Anthony soils are on terraces and fan remnants and have slopes of 0 to 12 percent. The mean annual precipitation is about 356 mm and the mean annual air temperature is about 6.1 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calcic Pachic Haploxerolls

TYPICAL PEDON: St. Anthony gravelly sandy loam, cultivated; on a terrace at an elevation of 1510 meters. When described on September 27, 1968 the soil was moist throughout. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 18 cm; brown (10YR 4/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure parting to moderate very fine granular; slightly hard, very friable, slightly sticky and slightly plastic; few fine and medium and common very fine roots; many very fine and few fine irregular pores; few pressure faces against gravel; about 20 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (15 to 36 cm thick)

A--18 to 30 cm; brown (10YR 5/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure parting to moderate very fine and fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine and few fine irregular pores; about 25 percent gravel; few pressure faces against gravel; neutral (pH 7.0); clear wavy boundary. (0 to 36 cm thick)

Bk--30 to 53 cm; brown (10YR 5/3) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; weak fine granular structure; hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; many very fine irregular pores; about 50 percent gravel; many pressure faces against gravel; discontinuous calcium carbonate coats on bottom surfaces of rock fragments; strongly effervescent; neutral (pH 7.2); gradual wavy boundary. (13 to 38 cm thick)

2Bk--53 to 152 cm; dark gray (10YR 4/1) extremely gravelly coarse sand; single grain; loose; few very fine roots; about 70 percent gravel; discontinuous calcium carbonate coats on bottom surfaces of rock fragments;strongly effervescent; neutral (pH 7.2)

TYPE LOCATION: Fremont County, Idaho; 1.6 km south, 805 meters east of St. Anthony; 198 meters north, 152 meters west of the southeast corner of section 12, T.7N., R.40E.

RANGE IN CHARACTERISTICS:
Mollic epipedon thickness: 50 to 100 cm
Depth to sandy-skeletal material (2Bk horizon): 50 to 100 cm
Depth to secondary carbonates: 20 to 51 cm
Control section total clay (weighted average): 8 to 18 percent
Control section rock fragments: 15 to 60 percent (weighted average is greater than 35 percent); 15 to 50 percent gravel, 0 to 20 percent cobbles
Mean annual soil temperature: 6.1 to 8.0 degrees C
Mean summer soil temperature: 15.0 to 18.9 degrees C
Soil reaction: neutral or slightly alkaline
Moisture regime: xeric; control section is dry for 45 to 70 consecutive days after the summer solstice

A or Ap horizons
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 2 to 3 moist
Chroma: 2 or 3 moist or dry
Texture: GR-SL, GR-L

Bk horizon
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 moist or dry
Fine-earth texture: L, SCL, SL or COSL with 15 to 65 percent total rock fragments; 15 to 60 percent gravel, 0 to 25 percent cobbles. The content of fine sand thru coarse sand is more than 50 percent
Clay: 15 to 23 percent

2Bk horizon
Value: 4 or 5 dry
Chroma: 1 to 4 dry
Fine-earth texture: LS, LCOS, S or COS with 35 to 90 percent total rock fragments; 35 to 90 percent gravel, 0 to 30 percent cobbles
Calcium carbonates (when present): thin coats on underside of rock fragments

COMPETING SERIES: These are the Calpac and Jimsage series. Calpac soils are deep and very deep to bedrock and have 18 to 25 percent clay in the particle-size control section. Jimsage and Calpac soils lack the sandy-skeletal lithologic discontinunity in the lower part of the particle-size control section.

GEOGRAPHIC SETTING:
Landscape: alluvial and outwash plains
Landform: terraces and broad swales on fan remnants
Elevation: 1,371 to 2,073 meters
Slope: 0 to 12 percent
Parent material: gravelly mixed alluvium
Mean annual air temperature: 3.3 [cr7]to 7.2 degrees C
Mean annual precipitation: 305 to 457[cr8] mm
Frost free period: 40 to 100 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Eginbench soils. The Eginbench soils have a loamy sand profile. Eginbench soils are also on terraces, but in somewhat poorly drained areas.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: well drained (subject to irrigation induced water table)
Runoff: negligible
Saturated hydraulic conductivity: high in the upper part and very high in the lower part

USE AND VEGETATION:
Major uses: irrigated hay, wheat, barley, oats, pasture, and some potatoes
Dominant native vegetation: big sagebrush and bunchgrasses

DISTRIBUTION AND EXTENT:
Distribution: Southeastern Idaho, MLRA 13
Extent: the series is not extensive

MLRA OFFICE RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Fremont County, Idaho, 1989

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from a depth of 0 to 53 cm
Particle size control section: from a depth of 25 to 100 cm
Soil temperature regime: frigid
Soil moisture regime: xeric

National Cooperative Soil Survey
U.S.A.