LOCATION WIMPEY IDEstablished Series
TAXONOMIC CLASS: Clayey over sandy or sandy-skeletal, smectitic over mixed, calcareous, frigid Cumulic Endoaquolls
TYPICAL PEDON: Wimpey silty clay--on a 1 percent slope at 4880 feet elevation in pasture. (Colors are for dry soil unless otherwise noted. When described on October 17, 1991, the soil was moist from the surface to 14 inches and saturated below 14 inches. A water table was present at 36 inches.)
Oe--0 to 1 inch; moderately decomposed roots, stems and leaves. (0 to 4 inches thick)
Ak1--1 to 4 inches; dark gray (10YR 4/1) silty clay, very dark gray (10YR 3/1) moist; few fine prominent dark yellowish brown (10YR 3/6) redox features; strong medium granular structure; very hard, friable, very sticky and very platic; many very fine, fine and medium roots; many fine and very fine tubular pores; slightly effervescent; few very fine soft masses of segregated lime; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 7 inches thick)
Ak2--4 to 15 inches; grayish brown (2.5Y 5/2) silty clay, very dark grayish brown (10YR 3/2) moist; common fine distinct black (N 2/0) redox concentrations; moderate medium subangular blocky structure; very hard, friable, very sticky and very plastic; many very fine, fine and medium roots; many fine and very fine tubular pores; slightly effervescent; few fine soft masses of segregated lime; 5 percent gravel; moderately alkaline (pH 8.3); clear smooth boundary. (0 to 11 inches thick)
Bg--15 to 28 inches; dark grayish brown (2.5Y 4/2) silty clay loam, very dark grayish brown (2.5Y 3/2) moist; few medium and common large prominent dark yellowish brown (10YR 4/6) and common medium and few large prominent black (N 2/0) redox concentrations and depletions; moderate medium subangular blocky structure; very hard, friable, very sticky and moderately plastic; few fine and very fine and common medium roots; many fine and very fine tubular pores; moderately alkaline (pH 7.9); abrupt wavy boundary. (8 to 26 inches thick)
2Cg1--28 to 42 inches; multicolored, dominantly olive gray (5Y 4/2) extremely gravelly coarse sand, dark gray (5Y 4/1) moist; single grain; loose; 55 percent gravel, 10 percent cobbles; neutral (pH 7.3); clear smooth boundary. (9 to 22 inches thick)
2Cg2--42 to 61 inches; multicolored, dominantly olive gray (5Y 4/2) extremely gravelly coarse sand, dark gray (5Y 4/1) moist; single grain; loose; 40 percent gravel, 30 percent cobbles; neutral (pH 7.1).
TYPE LOCATION: Lemhi County, Idaho; about 7.5 miles southeast of Baker, Idaho, about 1,590 feet north and 530 feet east of the southwest corner of sec. 5, T. 19N., R. 24.E. Latitude - 45 degrees, 56 minutes, 45 seconds North; Longitude - 113 degrees, 36 minutes, 2 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 40 to 42 degrees F.
Particle-size control section - Percent clay:
upper part - 35 to 50
lower part - 2 to 12
Mollic epipedon thickness - 24 to 30 inches
Depth to sand and gravel - 20 to 35 inches
Depth to seasonal high water table - 12 to 18 inches (March
to July)
Ak horizon
Hue - 2.5Y or 10YR
Value - 3 through 5 dry, 2 or 3 moist
Chroma - 0 through 2 dry and moist
Reaction - slightly through moderately alkaline
Bg horizons
Hue - 2.5Y or 5Y
Value - 4 or 5 dry, 2.5 through 4 moist
Chroma - 1 or 2 dry and moist
Reaction - slightly or moderately alkaline
Coarse fragments - 0 to 15 percent
Texture - SIC, SICL
2Cg horizon
Coarse fragments - 65 to 85 percent
Texture - GRX-LS, GRX-LCOS, CBX-LCOS, GRX-COS
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Wimpey soils are on flood plains. These soils formed in fine-textured alluvium over flood-deposited sand and gravel. Slopes are 0 to 2 percent. Elevations are 4,200 to 5,200 feet. The climate is cold and moist in winter and spring, and dry in summer. Average annual precipitation is 9 to 12 inches. Average annual temperature is 42 to 44 degrees F. The frost-free period is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ajax and Zeph soils. Zeph soils are poorly drained, have sandy-skeletal particle-size control sections and do not have a mollic epipedon. Ajax soils are in depressions on flood plains. Zeph soils are on remnant gravel bars on flood plains.
DRAINAGE AND PERMEABILITY: Poorly drained. Slow runoff. Permeability is slow in the upper part and very rapid in the lower part. This soil floods occasionally for brief periods in January through June.
USE AND VEGETATION: Mostly cultivated under flood irrigation for grass hay and pasture. The principal native vegetation is sedges, slender wheatgrass and willows.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lemhi County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 1 to 28 inches (the Ak1, Ak2 and Bg horizons)
Particle-size control section - the zone from 11 to 41 inches (part of the Ak2, the Bg and part of the 2Cg1 horizons)
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.