LOCATION MIDVALE IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Argixerolls
TYPICAL PEDON: Midvale silty clay loam, on a 1 percent slope at an elevation of 2,640 feet in a grain field. When described on September 18, 1979, the profile was dry throughout. (Colors are for air-dry soil unless otherwise stated.)
A1--0 to 4 inches; dark grayish brown (10YR 4/3) silty clay loam, very dark brown (10YR 2/2) moist; strong very fine granular structure; hard, firm, sticky, plastic; many fine roots; many fine irregular pores; neutral (pH 6.8); abrupt smooth boundary. (3 to 6 inches thick)
A2--4 to 10 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, firm, sticky, plastic; many fine and medium roots; common very fine tubular pores; common very dark brown (10YR 2/2) stains in the pores; neutral (pH 6.8) clear smooth boundary. (6 to 10 inches thick)
BA--10 to 14 inches; dark brown (7.5YR 4/2) clay, dark reddish brown (5YR 2/2) moist; moderate fine and medium prismatic structure parting to strong fine and medium subangular and angular blocky; extremely hard, very firm, very sticky, very plastic; common very fine roots; many very fine and fine tubular pores; common very dark brown (10YR 2/2) stains in pores; continuous moderately thick clay films on faces of peds and in pores; neutral (pH 7.0); clear smooth boundary. (2 to 9 inches thick)
Bt--14 to 19 inches; dark brown (7.5YR 4/2) clay, dark reddish brown (5YR 3/2) moist; strong medium prismatic structure parting to strong medium subangular blocky; extremely hard, very firm, very sticky, very plastic; common very fine roots on faces of the peds and few very fine in the peds; many very fine and fine tubular pores; continuous thick clay films on faces of peds and in pores; neutral (pH 7.0); clear smooth boundary. (2 to 8 inches thick)
Btb--19 to 30 inches; dark yellowish brown (10YR 4/4) clay, dark brown (10YR 3/3) moist; strong medium prismatic structure; extremely hard, very firm, very sticky, very plastic; few very fine roots; few fine tubular pores; continuous thick clay films on faces of peds and in pores; neutral (pH 7.0); abrupt wavy boundary. (9 to 13 inches thick)
Bkqb--30 to 39 inches; pale brown (10YR 6/3) loam, dark brown (10YR 4/3) moist; weak coarse prismatic structure; hard, friable, sticky, plastic; few very fine roots; common fine and medium tubular pores; a thin extremely hard and brittle discontinuous silica-iron pan caps the horizon; about 25 percent of the horizon contains splotches of primary calcium carbonate; few 2 to 4 inch krotovina; common thin clay films on vertical peds; neutral (pH 7.2); abrupt wavy boundary. (5 to 10 inches thick)
C1--39 to 56 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; massive; hard, firm, sticky, plastic; few very fine roots; many very fine and fine irregular and tubular pores; about 25 percent of the horizon is moderately calcareous; neutral (pH 7.2); clear smooth boundary. (2 to 20 inches thick)
C2--56 to 60 inches; yellowish brown (10YR 5/4) very fine sandy loam, dark yellowish brown (10YR 3/4) moist; massive; hard, firm; many very fine and fine irregular and tubular pores; neutral (pH 7.2).
TYPE LOCATION: Washington County, Idaho, about 2 miles northwest of Midvale; 2,580 feet west and 1,330 feet south of the northeast corner, sec. 7, T. 13 N. R. 3 W.
RANGE IN CHARACTERISTICS:
Depth to discontinuous duripan fragments - 20 to 40 inches
Depth to lacustrine sediments - 30 to 60 inches
Average annual soil temperature - 48 to 52 degrees F
A horizon
Value - 3 to 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry and moist
Bt horizons
Hue - 10YR or 7.5YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 to 4 dry, 2 or 3 moist
Textures - CL, SIC, or C
Clay content - 35 to 45 percent
Structure grade - moderate or strong
Structure size - medium or coarse
Structure type - prismatic, subangular blocky or angular blocky Carbonates are not present in all areas
C horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry and moist
Textures - L, SIL, CL, or VFSL
COMPETING SERIES: These are the Daphnedale, Keating, and Ramo series. Daphnedale, Keating, and Ramo soils lack silica cementation within 40 inches of the surface. Daphnedale and Keating soils have bedrock above 40 inches. Ramo soils have 15 to 35 percent rock fragments in the argillic horizon.
GEOGRAPHIC SETTING: Midvale soils are on terrace tops. Slopes range from 0 to 20 percent. Elevation ranges from 2,400 to 4,500 feet. The soil formed in old alluvium and underlying lacustrine sediments. The climate has warm summers with average annual precipitation of 16 to 22 inches, most of which falls as snow in winter. The average air temperature is about 46 to 50 degrees F. The frost-free period is 120 to 145 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Appledellia, Bakeoven, Reywat, and Newell. Appledellia soils have a very gravelly duripan. Bakeoven soils are less than 10 inches deep to basalt. Reywat soils are 10 to 20 inches deep to basalt. Newell soils are Pachic.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; slow permeability.
USE AND VEGETATION: Mainly used for small grain, hay and pasture. Native vegetation, where present, is bluebunch wheatgrass, Idaho Fescue, sandberg bluegrass, big sagebrush, and related forbs.
DISTRIBUTION AND EXTENT: Adams, Boise, and Washington Counties, Idaho. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Washington County, Idaho, 1992.
REMARKS: Sampled SCS National Soil Survey Laboratory No. S791D-087-003.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0-19 inches ( Al, Az, Ba, Bt horizons)
Argillic horizon - the zone from 10 to 39 inches (Bt, Btb horizons)
Clay content control section - 35 to 45 percent