LOCATION SWAYNE ID

Established Series
Rev. PNP-BDG-EMM
07/2013

SWAYNE SERIES

The Swayne series consists of very deep, well drained soils that formed in loess, alluvium and material weathered from granite. Swayne soils are on mountain ridges and benches, and canyon slopes on plateaus and have slopes of 10 to 55 percent. They have slow permeability. The average annual precipitation is about 24 inches and the average annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Ultic Palexeralfs

TYPICAL PEDON: Swayne silt loam, forested--on a 27 percent slope with a northeasterly aspect at an elevation of 2,000 feet. (Colors are for dry soil unless otherwise noted. When described on September 6, 1983, the profile was moist to 7 inches.)

Oi--0 to 1 inch; grass, leaves, and twigs. (0 to 2 inches thick)

A1--1 to 4 inches; brown (10YR 4/3) silt loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine irregular pores; neutral (pH 6.6); clear wavy boundary.

A2--4 to 8 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to moderate fine and medium granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, and common medium roots; many very fine irregular and tubular, and common fine tubular pores; few faint clay films on faces of peds and lining pores; neutral (pH 6.6); clear wavy boundary. (A horizons 5 to 12 inches thick)

BA--8 to 14 inches; yellowish brown (10YR 5/4) silty clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine, fine and medium roots; many very fine and fine tubular pores; common faint clay films on faces of peds and lining pores; common silt coats on faces of peds; slightly acid (pH 6.5); clear wavy boundary. (0 to 9 inches thick)

Bt/E--14 to 22 inches; B part brown (7.5YR 5/4) silty clay loam, dark brown (7.5YR 3/4) moist, E part light yellowish brown (10YR 6/4), dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; many very fine and fine tubular, and common very fine irregular pores; common faint clay films on faces of peds and lining pores; many faint silt coats on faces of peds; slightly acid (pH 6.5); abrupt wavy boundary. (0 to 9 inches thick)

Bt1--22 to 39 inches; brown (7.5YR 4/4) silty clay loam, dark reddish brown (5YR 3/4) moist; moderate medium prismatic structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; common very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; roots concentrated along prism faces; iron-manganese stains on prism faces; slightly acid (pH 6.2); gradual wavy boundary.

Bt2--39 to 56 inches; brown (7.5YR 5/4) silty clay, dark brown (7.5YR 3/4) moist; weak fine prismatic structure parting to moderate fine and medium angular blocky; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular, and few very fine irregular pores; common prominent, and many distinct clay films on faces of peds and lining pores; slightly acid (pH 6.4); clear wavy boundary. (Bt horizons 8 to 50 inches thick)

2Bt3--56 to 61 inches; brown (7.5YR 5/4) clay loam, brown (7.5YR 4/4) moist; weak fine prismatic structure parting to moderate fine angular blocky; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; many distinct clay films on faces of peds and lining pores; neutral (pH 7.2).

TYPE LOCATION: Clearwater County, Idaho; about 1 mile northeast of Ahsahka, Idaho; about 300 feet north and 150 feet west of the southeast corner of section 27, T. 37 N., R. 1 E.; Latitude - 46 degrees, 30 minutes, 57 seconds North; Longitude - 116 degrees, 18 minutes, 20 seconds West. USGS Ahsahka quadrangle.

RANGE IN CHARACTERISTICS:

Average annual soil temperature - 41 to 46 degrees F. (Frigid temperature regime)
Base saturation - 50 to 75 percent in some part of the argillic horizon.

A horizons
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 2 to 4 dry, 2 or 3 moist
Texture - silt loam or loam
Clay content - 16 to 26 percent
Rock fragments - 0 to 5 percent gravel
Reaction - slightly acid or neutral

BA horizon
Value - 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - silt loam, loam or silty clay loam
Clay content - 20 to 30 percent
Rock fragments - 0 to 5 percent gravel
Reaction - moderately acid to neutral

Bt/E horizons
Bt material:
Hue - 7.5YR or 10YR dry or moist
Value - 5 or 6 dry, 3 to 5 moist
Chroma - 3 or 4 dry and moist
Texture - silty clay loam, clay loam or silt loam
Clay content - 26 to 34 percent
Reaction - moderately acid or slightly acid

E material:
Hue - 7.5YR or 10YR dry or moist
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry, 3 to 6 moist
Texture - silt loam, silty clay loam or loam
Clay content - 23 to 27 percent
Rock fragments - 0 to 5 percent gravel
Reaction - moderately acid or slightly acid

Bt horizons
Hue - 7.5YR to 10YR dry, 5YR to 10YR moist
Value - 4 to 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Textures - silty clay loam, silty clay, silt loam, clay loam or clay
Clay content - 24 to 50 percent (weighted average greater than 35 percent)
Rock fragments - 0 to 10 percent gravel
Reaction - moderately acid to neutral

2Bt horizons
Hue - 7.5YR or 10YR dry or moist
Value - 5 to 7 dry, 4 to 6 moist
Chroma - 2 to 4 dry, 3 to 6 moist
Texture - silty clay loam, clay loam or clay
Clay content - 34 to 42 percent
Rock fragments - 0 to 10 percent gravel
Reaction - strongly acid to neutral

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Swayne soils are on benches, ridges, and canyon slopes at elevations of 1,000 to 3,500 feet and have slopes of 10 to 55 percent. These soils formed in loess and alluvium over material weathered from granite. The average annual temperature ranges from 40 to 45 degrees F. The average annual precipitation ranges from 23 to 30 inches and the frost-free season is 80 to 125 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahsahka, Fordcreek, Johnson and Texascreek series. Fordcreek soils are fine-loamy and have a paralithic contact at 40 to 60 inches and are on south, convex positions. Johnson soils have a mollic epipedon, are fine-loamy and are in concave northerly aspects. Texascreek soils are coarse-loamy, have a mesic soil temperature regime and are on convex, westerly aspects.

DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff. Slow permeability.

USE AND VEGETATION: Primary uses of this soil are for timber production, livestock grazing, wildlife habitat and homesite development. The natural vegetation is Douglas-fir, ponderosa pine, common snowberry, mallow ninebark, creambrush oceanspray, columbia brome, and heartleaf arnica.

DISTRIBUTION AND EXTENT: Northern Idaho; the Swayne series is not extentsive. MLRA 43A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Clearwater County, Idaho, 2003.

REMARKS: Diagnostic horizons and other features recognized in this pedon:

Ochric epipedon - the zone from 0 to 8 inches (Oi, A1 and A2 horizons).

Argillic horizon - the zone from 22 to 61 inches (Bt1, Bt2, 2Bt3 horizons).

Particle-size control section - the zone from 22 to 42 inches (Bt1 and part of Bt2 horizon).

National Cooperative Soil Survey
U.S.A.