LOCATION SHEETSFLAT WY
Tentative Series
IRD. DEW/JCK
02/2017
SHEETSFLAT SERIES
The Sheetsflat series consist of very deep, moderately well drained soils that formed in alluvium. These soils are on alluvial fans and stream terraces. Slopes are 0 to 8 percent. Mean annual precipitation is about 309 mm, and mean annual air temperature is about 7 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aquic Haplargids
TYPICAL PEDON: Sheetsflat, sandy clay loam 2 percent slope in cropland at an elevation of 1,527 meters (colors are for dry soil unless otherwise noted).
Ap--0 to 10 cm; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist; moderate fine granular structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots throughout; slightly effervescent; slightly alkaline (pH 7.7); clear smooth boundary (10 to 30 cm thick)
Bt--10 to 33 cm; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine and few fine roots throughout, common very fine and fine tubular pores; 10 percent distinct clay films on faces of peds; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (20 to 60 cm thick)
C--33 to 79 cm; light yellowish brown (10YR 6/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots throughout, common very fine tubular pores; 3 percent 7.5YR 5/6 oxidized iron masses, 5 percent 2.5Y 6/2 iron depletions; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (20 to 70 cm thick)
Btkb--79 to 159 cm; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots throughout; 5 percent distinct clay films on faces of peds; finely disseminated carbonates and 3 percent fine moist threadlike calcium carbonate masses in the matrix; 5 percent fine 7.5YR 5/6 oxidized iron masses, 10 percent 2.5Y 6/1 iron depletions; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 80 cm thick)
Bkb--159 to 200 cm; light yellowish brown (10YR 6/4) fine sandy loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; 2 percent fine moist threadlike calcium carbonate masses in the matrix; 3 percent 7.5YR 5/6 oxidized iron messes, 5 percent 2.5Y 6/1 iron depletions; slightly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Park county Wyoming; 704 meters south and 30 meters east of the northwest corner of section 33, T. 51N., R. 98W.; Sheets Flat USGS quadrangle; latitude 44 degrees 21 minutes 1.61 seconds N. and longitude 108 degrees 39 minutes 14.63 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 8 to 10 degrees C
Depth to seasonal high water table - 90 to 180 cm
Rock fragments - 0 to 15 percent gravel
Note: where cultivated, saturation is, in part, from intensive flood irrigation.
A horizon:
Hue: 7.5YR to 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 3 or 4
Texture: loam, sandy clay loam or clay loam
Clay content: 18 to 30 percent
Rock fragments: 0 to 15 percent gravel
Electrical conductivity: 2 to 8 mmhos/cm
Reaction: 7.6 to 8.0
Bt horizon:
Hue: 7.5YR to 2.5Y
Value: 5 or 6 dry; 3, 4 or 5 moist
Chroma: 3 or 4
Texture: sandy clay loam, clay loam or loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 15 percent gravel
Electrical conductivity: 2 to 8 mmhos/cm
Reaction: 7.6 to 8.0
C horizon:
Hue: 7.5YR to 2.5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 3, 4 or 6
Texture: fine sandy loam, sandy loam, loam or very fine sandy loam
Clay content: 10 to 20 percent
Rock fragments: 0 to 15 percent gravel
Electrical conductivity: 2 to 4 mmhos/cm
Reaction: 7.6 to 8.0
Btkb horizon:
Hue: 7.5YR to 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: sandy clay loam, clay loam, silty clay loam or loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Electrical conductivity: 2 to 4 mmhos/cm
Reaction: 8.0 to 8.4
Bkb horizon:
Hue: 7.5YR to 2.5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 3, 4 or 6
Texture: fine sandy loam, sandy loam, loam or very fine sandy loam
Clay content: 10 to 18 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 10 percent
Electrical conductivity: 2 to 4 mmhos/cm
Reaction: 7.8 to 8.2
COMPETING SERIES:
Fenton (WY) - have horizons of secondary calcium carbonate accumulation in the surface mantle; have more than 15 percent rock fragments in the lower part of the subsoil
Jimmerfield (WY) - have horizons of secondary calcium carbonate accumulation in the surface mantle; have hues redder than 7.5YR
Manzanar (CA) - have horizons of strong gleying; have a lithologic discontinuity
Roachgulch (WY) - do not have horizons of secondary calcium carbonate accumulation
Snydersditch (WY) - have horizons of secondary calcium carbonate accumulation in the surface mantle
GEOGRAPHIC SETTING:
Landform - alluvial fans and stream terraces
Elevation - 1,400 to 1,700 meters
Slope - 0 to 8 percent slopes
Parent material - alluvium
Mean annual precipitation - 254 to 356 mm
Mean annual air temperature - 6 to 8 degrees C
Frost-free period - 110 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS: None
DRAINAGE AND PERMEABILITY: Moderately well drained; moderate to moderately rapid permeability.
USE AND VEGETATION: Sheetsflat soils are used mainly for irrigated alfalfa and grass hay.
DISTRIBUTION AND EXTENT: Sheetsflat soils are of small extent in northwest Wyoming. MLRA 32.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Park County, Wyoming; 2016. The name is taken from a local landscape feature.
REMARKS:
Ochric epipedon - from 0 to 20 cm (Ap horizon)
Argillic horizon - from 10 to 33 cm (Bt horizon)
Redoximorphic concentrations- from 33 to 200 cm (C, Btkb and Bkb horizons)
Redoximorphic depletions - from 33 to 200 cm (C, Btkb and Bkb horizons)
Particle-size control section - from 10 to 33 cm (Bt horizon)
Sheetsflat soils have a mesic temperature regime and an aridic moisture regime bordering on ustic.
National Cooperative Soil Survey
U.S.A.