LOCATION BRIDGEFORE WY
Tentative Series
Rev. TAG-DMM-RJS
04/2011
BRIDGEFORE SERIES
The Bridgefore series consists of very deep, well drained soils that formed in slope alluvium and/or colluvium over residuum derived from metamorphic and sedimentary rock. These soils are on mountain slopes and ridges. Slopes are 5 to 30 percent. Mean annual precipitation is about 550 mm, and mean annual air temperature is about 1 degree C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Umbric Haplocryalfs
TYPICAL PEDON: Bridgefore gravelly loam, in coniferous forest (colors are for dry soil unless otherwise noted).
A--0 to 20 cm; dark reddish gray (5YR 4/2) gravelly loam, dark reddish brown (5YR 3/2) moist; moderate fine granular structure; soft, very friable, nonsticky, nonplastic; many fine roots; many fine interstitial pores; 15 percent gravel; neutral (pH 6.7); clear smooth boundary. (12 to 24 cm thick)
Bt1--20 to 54 cm; reddish brown (5YR 5/3) very gravelly loam, reddish brown (5YR 4/3) moist; moderate fine subangular blocky structure; soft, friable, slightly sticky, slightly plastic; many fine roots; many fine interstitial pores; 10 percent clay films on all faces of peds; 50 percent gravel; slightly acid (pH 6.3); gradual smooth boundary.
Bt2--54 to 100 cm; reddish brown (5YR 5/3), very gravelly loam, reddish brown (5YR 4/3), moist; moderate fine subangular blocky structure; moderately hard, friable, moderately sticky, moderately plastic; many fine roots; many fine interstitial pores; 20 percent clay films on all faces of peds; 50 percent gravel; moderately acid (pH 5.7); gradual smooth boundary. (combined thickness of Bt horizons - 50 to 90 cm)
BC1--100 to 165 cm; reddish yellow (7.5YR 7/8) clay loam, reddish yellow (7.5YR 7/8) moist; moderate fine angular blocky structure; hard, firm, moderately sticky, moderately plastic; few very fine vesicular pores; 2 percent gravel; very strongly acid (pH 4.9); abrupt smooth boundary.
BC2--165 to 200 cm; yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky, moderately plastic; few very fine vesicular pores; 2 percent gravel; very strongly acid (pH 4.8); abrupt smooth boundary. (combined thickness of BC horizons - 60 to 120 cm)
C--200 to 231 cm; reddish yellow (7.5YR 7/6) sandy loam, reddish yellow (7.5YR 7/6) moist; massive; hard, firm, nonsticky, nonplastic; few very fine vesicular pores; 2 percent gravel; very strongly acid (pH 4.8).
TYPE LOCATION: Sublette County, Wyoming; located approximately 1,985 feet south and 1,790 feet east of the northwest corner of section 4, T 27N, R 114W; USGS Lake Mountain, Wyoming topographic quadrangle; 42 degrees 21 minutes 22.00 seconds north latitude and 110 degrees 23 minutes 53.00 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil temperature - 1.5 to 3.5 degrees C.
Depth to top of argillic horizon - 12 to 24 cm
Base saturation - less than 50 percent in some part between the upper boundary of the argillic horizon to a depth of 125 cm
Note: The A horizon does not meet the umbric epipedon thickness requirement of 25 cm.
A horizon
Hue: 5YR or 7.5YR; dry or moist
Value: 3 or 4; dry
Chroma: 2 or 3; dry or moist
Clay content: 10 to 18 percent
Rock fragments: 15 to 25 percent gravel
Reaction: pH 6.3 to 7.0
Bt1, Bt2 horizons
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4; dry or moist
Texture: clay loam, loam
Clay content: 20 to 35 percent
Rock fragments: 35 to 55 percent gravel
Reaction: pH 5.6 to 6.3
BC1, BC2 horizons
Hue: 5YR or 7.5YR; dry or moist
Value: 5 to 7 dry; 4 to 7 moist
Chroma: 6 or 8; dry or moist
Texture: clay loam, loam
Clay content: 20 to 32 percent
Rock fragments: 0 to 15 percent gravel
Reaction: pH 4.5 to 5.5
C horizon
Hue: 5YR or 7.5YR; dry or moist
Texture: sandy loam, loam
Clay content: 12 to 22 percent
Rock fragments: 0 to 15 percent gravel
Reaction: pH 4.5 to 5.5
COMPETING SERIES:
Bargeville (WY) - is deep to a lithic contact
Wapshilla (ID) - the subsoil does not have strongly or very strongly acid reaction classes
GEOGRAPHIC SETTING:
Landform - mountain slopes, ridges
Elevation - 2500 to 2810 meters
Slope - 5 to 30 percent
Parent material - slope alluvium and/or colluvium over residuum derived from metamorphic and sedimentary rock
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 500 to 760 mm with peak periods of precipitation occurring during the spring
Mean annual air temperature - 0.5 to 3.0 degrees C.
Frost-free period - 25 to 45 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Bridgefore soils are primarily used for timberland and forestry. The potential native vegetation is lodgepole pine, subalpine fir, elk sedge, pinegrass, and other miscellaneous shrubs and forbs.
DISTRIBUTION AND EXTENT: Bridgefore soils are of small extent in southwestern Wyoming, MLRA - 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Sublette County, Wyoming, 2011. The series name is coined from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 20 cm (A horizon)
Argillic horizon - from 20 to 100 cm (Bt1, Bt2 horizons)
Particle-size control section - from 20 to 70 cm (Bt1, part of Bt2)
Bridgefore soils have a cryic temperature regime and an udic moisture regime.
National Cooperative Soil Survey
U.S.A.