LOCATION STOFFER WY
Tentative Series
IRD DJP-CBR
04/2018
STOFFER SERIES
The Stoffer series consists of very deep, well drained soils that formed in slope alluvium and colluvium derived from conglomerate. These soils are on fan remnants and hillslopes. Slopes are 2 to 20 percent. Mean annual precipitation is about 280 mm, and mean annual air temperature is about 4.0 degrees C.
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Calcixerepts
TYPICAL PEDON: Stoffer clay, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 9 cm; brown (7.5YR 5/3) clay, brown (7.5YR 4/3) moist; weak fine granular structure; very hard, very firm, very sticky, very plastic; few medium and common very fine roots between peds; common fine irregular and few fine tubular pores; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (7 to 12 cm thick)
Bk1--9 to 24 cm; brown (7.5YR 4/4) clay, brown (7.5YR 4/4) moist; moderate very coarse angular blocky structure; very hard, very firm, very sticky, very plastic; common very fine roots between peds; few fine tubular pores; 10 percent fine calcium carbonate masses in matrix; violently effervescent; 20 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); clear smooth boundary.
Bk2--24 to 45 cm; reddish brown (5YR 4/4) clay, reddish brown (5YR 4/4) moist; moderate very coarse platy structure; very hard, very firm, very sticky, very plastic; few fine tubular pores; 10 percent fine calcium carbonate masses in matrix; violently effervescent; 20 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); clear smooth boundary. (combined thickness of the Bk1 and Bk2 horizons is 30 to 45 cm)
Bk3-- 45 to 68 cm; yellowish red (5YR 4/6) clay loam, reddish brown (5YR 4/4) moist; moderate fine subangular blocky structure; very hard, very firm, very sticky, very plastic; 3 percent fine calcium carbonate masses in matrix; strongly effervescent; 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary. (20 to 28 cm thick)
BCk1-- 68 to 110 cm; yellowish red (5YR 4/6) clay loam, yellowish red (5YR 4/6) moist; massive; moderately hard, firm, moderately sticky, moderately plastic; calcium carbonate, finely disseminated; strongly effervescent; 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary. (40 to 48 cm thick)
BCk2-- 110 to 150 cm; strong brown (7.5YR 4/6) clay loam, brown (7.5YR 4/4) moist; massive; moderately hard, firm, moderately sticky, moderately plastic; 1 percent gravel; calcium carbonate, finely disseminated and 50 percent calcium carbonate coats on rock fragments; strongly effervescent; 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).
TYPE LOCATION: Lincoln County, Wyoming; USGS Beckwith, Wyoming, topographic quadrangle; 41 degrees 58 minutes 20.93 seconds north latitude and 110 degrees 56 minutes 11.19 seconds west longitude, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature -- 3.0 to 7.0 degrees C.
Depth to calcic horizon -- 7 to 12 cm
Linear extensibility 0 to 100 cm -- 6.0 to 6.5
Particle-size control section (weighted averages)
Clay content -- 36 to 43 percent
A horizon
Hue: 5YR or 7.5YR, dry or moist
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3 or 4, dry or moist
Clay content: 42 to 48 percent
Reaction: pH 8.0 to 8.6
Bk1 and Bk2 horizons
Hue: 5YR or 7.5YR, dry or moist
Value: 4 or 5, dry or moist
Chroma: 4 or 6, dry or moist
Clay content: 42 to 52 percent
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 8.0 to 8.6
Bk3 horizon
Hue: 5YR or 7.5YR, dry or moist
Value: 4 or 5, dry or moist
Chroma: 4 or 6, dry or moist
Clay content: 32 to 38 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.0 to 8.4
BCk horizons
Hue: 5YR or 7.5YR, dry or moist
Value: 4 or 5, dry or moist
Chroma: 4 or 6, dry or moist
Texture (less than 2 mm fraction) - clay loam, loam
Clay content: 25 to 32 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.8 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform -- fan remnants and hillslopes
Elevation -- 1,890 to 2,010 meters
Slope -- 2 to 20 percent
Parent material -- slope alluvium and colluvium derived from conglomerate
Climate -- long, cold winters; cool, moist springs; short, warm summers
Mean annual precipitation -- 225 to 375 mm with peak periods of precipitation occurring during the winter
Mean annual air temperature -- 2.0 to 6.0 degrees C.
Frost-free period -- 40 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, 0.01 to 5.0 um/sec.
USE AND VEGETATION: Stoffer soils are primarily used for rangeland. The potential native vegetation is early sagebrush, bottlebrush squirreltail, thickspike wheatgrass and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Stoffer soils are of small extent in southwestern Wyoming. MLRA 13.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Lincoln County, Wyoming, 2018. The name is derived from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- 0 to 9 cm (A horizon)
Calcic horizon -- 9 to 45 cm (Bk1 and Bk2 horizon)
Vertic feature -- 0 to 100 cm (A, Bk1, Bk2, Bk3, and part of BCk1 horizons)
Particle-size control section -- 25 to 100 cm (part of the Bk1, Bk2, Bk3 and part of the BCk1 horizons)
Stoffer soils have a frigid temperature regime and a xeric moisture regime.
Taxonomic version: Twelfth edition, 2014
National Cooperative Soil Survey
U.S.A.