LOCATION SMIDALE IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Pachic Haploxerolls
TYPICAL PEDON: Smidale very channery silt loam--on a 60 percent convex slope with a northwest aspect at 5,000 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on September 1, 1994 the soil was dry to 25 inches and slightly moist below.)
Oi--0 to 1 inch; slightly decomposed plant material composed of leaves and grass.
A1--1 to 3 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; strong very fine and fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine irregular pores; 35 percent channers (80 percent are less than 5 mm across); slightly acid (pH 6.5); clear smooth boundary. (2 to 4 inches thick)
A2--3 to 9 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; strong very fine and fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular and common fine and very fine tubular pores; 35 percent channers (80 percent are less than 5 mm across); neutral (pH 6.6); clear smooth boundary. (6 to 11 inches thick)
Bw1--9 to 26 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots; common very fine and fine tubular pores; 40 percent channers (80 percent are less than 5 mm across); neutral (pH 6.8); clear smooth boundary. (4 to 17 inches thick)
Bw2--26 to 39 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots; common very fine and fine tubular pores; 45 percent channers (80 percent are less than 5 mm across); neutral (pH 6.8); gradual wavy boundary. (10 to 13 inches thick)
Bw3--39 to 46 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; common very fine and medium roots; common very fine and few fine tubular pores; 45 percent channers (80 percent are less than 5 mm across); neutral (pH 7.1); gradual wavy boundary. (10 to 13 inches thick)
Bw4--46 to 61 inches; very dark grayish brown (10YR 3/2) very channery silt loam, black (10YR 2/1) moist; moderate medium and coarse subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; common very fine and medium and few coarse roots; common very fine and few fine tubular pores; 50 percent channers (80 percent are less than 5 mm across); neutral (pH 7.1).
TYPE LOCATION: Franklin County, Idaho; about 6.5 miles northeast of Preston; about 150 feet east and 1,800 feet south of the northwest corner of section 28, T. 14 S., R. 40 E.; USGS Riverdale 7.5 minute topographic quadrangle; 42 degrees 10 minutes 43 seconds north latitude and 111 degrees 47 minutes 54 seconds west longitude, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry for 45 to 60 consecutive days in the 4 months following the summer solstice; Xeric moisture regime.
Mean annual soil temperature - 42 to 46 degrees F.
Mollic epipedon thickness - 50 inches or more.
Particle-size control section - Clay content: Averages 20 to 27 percent; Rock fragments: 35 to 60 percent, mainly channers.
A horizons
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Clay content: 14 to 24 percent.
Organic matter content: 4 to 6 percent.
Reaction: Slightly acid or neutral.
Bw1 and Bw2 horizons
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 2 or 3 dry, 1 through 3 moist.
Texture: Very channery silt loam or very channery loam.
Clay content: 16 to 27 percent.
Organic matter content: 3 to 5 percent.
Bw3 and Bw4 horizons
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 2 or 3 dry, 1 through 3 moist.
Texture: Very channery clay loam, very channery silt loam, very channery loam, or extremely channery loam.
Clay content: 24 to 30 percent.
Organic matter content: 1 to 4 percent.
COMPETING SERIES: These are the Baldridge, Beehunt (T), Burgi, Chambeam, Climine, Ginser, Glean, Lambring, Rondowa, Shorthike, Sinker, St. Anthony, Webfoot, Westbutte, and Willynat series.
Baldridge soils have mollic epipedons 20 to 35 inches thick and have coarse textured C horizons. Beehunt soils are dominated by cobbles and have mollic epipedons less than 50 inches thick. Burgi soils are calcareous beginning at about 40 inches. Chambeam soils have mollic epipedons 20 to 40 inches thick, C horizons, and bedrock at 40 to 60 inches. Climine soils have mollic epipedons 20 to 30 inches thick and subhorizons with durinodes in a friable matrix or silica coats and pendants on rock fragments. Sinker and Westbutte soils have a lithic contact at depths of 20 to 40 inches. Ginser soils have a paralithic contact at a depth of 20 to 40 inches. Glean soils have a particle-size control section with 8 to 18 percent clay. Lambring soils have a mollic epipedon 20 to 40 inches thick and do not have B horizons. Rondowa soils have mollic epipedons 20 to 30 inches thick, are influenced by volcanic ash in the upper part of the profile, and do not have B horizons. Shorthike soils have mollic epipedons less than 50 inches thick, have 10 to 15 percent clay, and are dominated by gravel in the particle-size control section. St. Anthony soils are moderately deep to coarse sand and gravel. Webfoot soils average 5 to 15 percent clay in the particle-size control section, are somewhat poorly drained, and have a saturated layer above 40 inches for 90 or more consecutive days. Willynat soils have 5 to 15 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Smidale soils are mountains. They generally occur on north-facing backslope positions. These soils formed in colluvium derived from tuffaceous shale with some loess influence. Slopes are 20 to 60 percent. Elevation ranges from 4,600 to 6,000 feet. The mean annual precipitation is 16 to 19 inches, the mean annual air temperature is 41 to 45 degrees F., and the frost-free period is 70 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Sanyon, Softback, and Staberg soils. Sanyon and Staberg soils are less than 40 inches deep. Softback and Staberg soils have mollic epipedons less than 40 inches thick and have argillic horizons. Sanyon soils are on convex slopes to the sides of or above Smidale soils. Staberg and Softback soils are on similar slopes to Smidale under a cover of sagebrush and bunchgrass.
DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity).
USE AND VEGETATION: Smidale soils are used mainly for rangeland. The current vegetation is bigtooth maple with an understory of bunch grasses.
DISTRIBUTION AND EXTENT: Southeastern Idaho. These soils are not extensive with about 1,140 acres of the series mapped to date. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Franklin County, Idaho, 1997. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 1 to 61 inches (A1, A2, Bw1, Bw2, Bw3, and Bw4 horizons).
Particle-size control section - The zone from 10 to 40 inches (Bw2 horizon and parts of the Bw1 and Bw3 horizons).
The superactive cation exchange activity class is estimated based on entries for data elements in NASIS.