LOCATION SWENCAN                 ID

Tentative Series
IRD. FRK/SM/MPR
01/2015

SWENCAN SERIES

The Swencan series consists of moderately deep, well drained soils that formed in eolian deposits and alluvium over basalt. Swencan soils have slopes of 0 to 12 percent and are on nearly level to rolling, wide, lava-filled valley floors. The mean annual precipitation is about 380 millimeters, and the mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Typic Haploxerolls

TYPICAL PEDON: Swencan fine sandy loam, located on a southwest facing slightly concave slope of 3 percent and elevation of 1,670 meters; when described on April 13, 1989, the soil was slightly moist throughout (Colors are for dry soil unless otherwise noted)

A1--0 to 10 cm; dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; very thick platy parting to moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine to fine roots; common very fine to fine tubular pores; 1 percent gravel; neutral (pH 7.1); abrupt smooth boundary

A2--10 to 38 cm; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky parting to moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine irregular and common very fine to fine tubular pores; 1 percent gravel; neutral (pH 7.2); abrupt smooth boundary

Bw1--38 to 58 cm; yellowish brown (10YR 5/4) fine sandy loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine roots; common very fine irregular and few very fine to fine tubular pores; slightly alkaline (pH 7.4); clear smooth boundary

Bw2--58 to 76 cm; yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 3/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common very fine irregular and few very fine tubular pores; slightly alkaline (pH 7.6); clear smooth boundary

Bw3--76 to 81 cm; light yellowish brown (10YR 6/4) sandy loam, brown (7.5YR 4/4) moist; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine irregular pores; slightly alkaline (pH 7.6); abrupt irregular boundary

2R--81 cm; vesicular basalt

TYPE LOCATION: Caribou County, Idaho; about 5 kilometers east of Bancroft, Idaho; 747 meters east and 91 meters north of the southwest corner, sec. 19, T.8S., R.40E., Boise Meridian; Talmage, Idaho USGS quadrangle; 42.7081 degrees north latitude, 111.8281 degrees west longitude WGS84; UTM 432188 meters east, 4728728 meters north, zone 12N

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C (frigid soil temperature regime)
Depth to lithic contact - 50 to 100 cm
Thickness of mollic epipedon - 20 to 50 cm

Particle-size control section-
Clay content - 6 to 18 percent
Rock fragments - 0 to 10 percent basalt gravel

A Horizons
Value - 4 or 5 dry
Chroma - 2 or 3 dry or moist
Clay content - 10 to 18 percent
Rock fragments - 0 to 10 basalt gravel
Thickness - 20 to 45 cm

Bw horizons
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 2 or 3 dry or moist
Fine earth texture - Fine sandy loam, sandy loam
Clay content - 6 to 15 percent
Reaction - 6.8 to 7.7
Rock fragments - 0 to 10 percent basalt gravel
Thickness - 34 to 57 cm

COMPETING SERIES:
Cowers - Greater than 150 cm to a lithic contact
McCollum - Greater than 150 cm to a lithic contact
Takeuchi - Greater than 15 percent rock fragments in the particle-size control section; typically have paralithic material from granitic lithologies

GEOGRAPHIC SETTING:
Parent material - Eolian sediment and alluvium
Landscape - Valleys
Landform - Nearly level to rolling, wide, lava-filled valley floors
Slope - 0 to 12 percent
Elevation - 1,650 to 1,880 meters
Climate - Warm, dry summers; cool, moist winters
Mean annual precipitation - 350 to 500 millimeters
Mean annual air temperature - 3 to 7 degrees C
Frost free duration - 60 to 90 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Arbone - Greater than 150 cm to a lithic contact; calcic horizons; smooth to slightly convex positions
Bancroft - Greater than 150 cm to a lithic contact; argillic horizons; smooth to slightly concave positions
Kackley - Calcic horizons; slightly convex positions
Rexburg - Greater than 150 cm to a lithic contact; calcic horizons; smooth to slightly concave positions

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class - Well drained
Ksat - High

USE AND VEGETATION:
Use - Livestock grazing, wildlife habitat, common crops of wheat, barley, potatoes, alfalfa
Potential natural vegetation - Bluebunch wheatgrass, basin wild rye, basin big sagebrush

DISTRIBUTION AND EXTENT: Eastern Idaho Plateaus, Idaho; MLRA 13; small extent

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

SERIES PROPOSED: Caribou County, Idaho, 2015; name is taken from a nearby canyon

REMARKS:
Particle-size control section - 25 to 81 cm
Mollic epipedon - A horizons
Lithic contact - Top of R horizon

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National Cooperative Soil Survey
U.S.A.