LOCATION SWANNER            ID+NV WY

SWANNER SERIES

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haploxerolls

TYPICAL PEDON: Swanner extremely stony loam, rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 5 inches; grayish brown (10YR 5/2) extremely stony loam, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; 40 percent channers, 10 percent flagstones, and 25 percent stones; mildly alkaline (pH 7.4); clear wavy boundary. About 40 percent of the surface is covered by light gray (N 6/) angular channers or platy fragments 0.2 to 0.5 inch across, flagstones, and stones of rhyolite or rhyolitic tuff. (4 to 7 inches thick)

Bw--5 to 11 inches; brown (10YR 5/3) extremely stony loam, dark brown (10YR 3/3) moist; weak, very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots matted on top of rock fragments; many very fine tubular pores; 25 percent stones, 30 percent flagstones, and 9 percent channers; noncalcareous except thick lime coating or pendants on lower side of rock fragments; mildly alkaline (pH 7.6); abrupt wavy boundary. (4 to 8 inches thick)

Bk--11 to 15 inches; light gray (10YR 7/2) extremely stony loam, grayish brown (10YR 5/2) moist; massive; soft, very friable, slightly sticky and slightly plastic; few very fine roots matted on top of rock fragments; common very fine tubular pores; 40 percent stones, 30 percent flagstones, and 10 percent channers; strongly effervescent; moderately alkaline (pH 8.0); abrupt irregular boundary. (2 to 9 inches thick)

R--15 inches; light gray (N 7/) rhyolite or rhyolitic tuff bedrock, gray (N 5/) moist; rock is lightweight and porous and has absorbed some lime.

TYPE LOCATION: Teton County, Idaho; about 11 miles west of Tetonia; 300 feet west and 100 feet south of the northeast corner of the southeast 1/4 of section 16, T. 6 N., R. 43 E.

RANGE IN CHARACTERISTICS:

Thickness of mollic epipedon - 8 to 17 inches
Depth to bedrock - 10 to 20 inches
Rock fragments in the control section - 35 to 80 percent
Average annual soil temperature - 40 to 47 degrees F

A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Reaction - neutral through moderately alkaline

Bw horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Clay content - 12 to 22 percent
Reaction - mildly alkaline or moderately alkaline
Rock fragments - 50 to 80 percent
Texture - STV-L, STX-L

Bk horizon where present
Value - 6 or 7 dry
Value - 4 or 5 moist
Chroma - 2 through 4 dry or moist
Clay content - 12 to 22 percent

Reaction - mildly alkaline or moderately alkaline
Rock fragments - 50 to 80 percent
Texture - STV-L, STX-L

COMPETING SERIES: These are the Agassiz, Anatone, Bocker, Cedaran, Falula, Foxol, Little Pole, Rexmont, and Van Wagoner series. The Agassiz soils are somewhat excessively or excessively drained. The Anatone and Bocker soils have hue of redder than 10YR in the B horizons. The Cedaran and Little Pole soils lack lime. Falula soils have hue of 7.5YR or redder. Foxol soils lack lime and have B horizons that are slightly or medium acid. Rexmont soils lack horizons of secondary carbonate accumulation. Van Wagoner soils lack lime and are neutral to medium acid in the lower part of the profile.

GEOGRAPHIC SETTING: Swanner soils are on mountain slopes and ridges. Slopes range from 0 to 80 percent. They formed in loess and silty alluvium and material weathered from andesite and other igneous rocks. The average annual precipitation ranges from 12 to 16 inches and the average annual temperature ranges from 39 to 45 degrees F. Frost-free season is 70 to 110 days. Elevation ranges from 4,500 to 7,000 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Araveton, Ard, Hondoho, Rammel, Tetonia, and Watercanyon (T) soils. The Araveton, Ard, Hondoho, and Watercanyon soils lack lithic contact. Tetonia and Watercanyon soils formed in deep loess and are coarse-silty. Araveton soils are on footslopes below the Swanner soils. Tetonia soils are on loess mantled uplands above the Swanner soils. Ard and Rammel soils are on mountain slopes where the overlying mantel is thicker. The Watercanyon soils dominantly are on south and west-facing slopes of mountains and foothills where associated with Swanner. Hondoho soils are on east-facing concave slopes and lower west-facing convex slopes where associated with Swanner.

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

USE AND VEGETATION: The Swanner series is used mainly for grazing. The potential natural vegetation is mainly low sagebrush and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Southeastern Idaho. This series is moderately extensive.

MLRA OFFICE RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Teton County, Idaho, 1972.