LOCATION CASSYHILL IDTentative Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Lithic Ultic Haploxerolls
TYPICAL PEDON: Cassyhill very gravelly ashy silt loam, forested; on a southwest-facing convex slope of 39 percent at an elevation of 3,130 feet. Pedon was described on September 20, 2005 and was dry throughout. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed leaves, needles and twigs mixed with 1980 Mt. St. Helens volcanic ash. (0.5 to 1 inch thick)
A--1 to 7 inches; very dark grayish brown (10YR 3/2) very gravelly ashy silt loam, grayish brown (10YR 5/2) dry; moderate very fine and fine subangular blocky structure parting to moderate fine granular; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine and fine tubular pores; 40 percent gravel; neutral (pH 6.6); clear smooth boundary. (2 to 11 inches thick)
AB--7 to 11 inches; dark brown (10YR 3/3) very gravelly ashy loam, brown (10YR 5/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine roots, few very coarse roots; many very fine and fine tubular pores; 35 percent gravel and 5 percent paragravel, 10 percent channers, 5 percent cobbles; slightly acid (pH 6.1); clear smooth boundary. (2 to 7 inches thick)
C--11 to 14 inches; dark yellowish brown (10YR 4/4) extremely channery loam, pale brown (10YR 6/3) dry; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common fine and medium roots; many very fine and fine tubular pores; 20 percent gravel and 10 percent paragravel, 20 percent cobbles and 5 percent paracobbles, 20 percent channers and 5 percent parachanners; moderately acid (pH 5.6); gradual wavy boundary. (3 to 10 inches thick)
R--14 to 17 inches; strongly cemented, highly fractured siltite; common fine and coarse roots between fractures approximately 4 to 8 inches apart.
TYPE LOCATION: Benewah County, Idaho; about 1000 feet south and 2150 feet west of the northeast corner section 9, T.46N., R.2W. Latitude 47 degrees, 21 minutes, 9 seconds North; Longitude 116 degrees, 35 minutes, 44 seconds West; NAD 83; USGS St. Maries quadrangle.
RANGE IN CHARACTERISTICS:
(Depth to diagnostic horizons and features measured from the top of the first mineral layer.)
Soil moisture - usually dry for 60 to 75 days mid-July to September, moist October to mid-July (xeric moisture regime)
Average annual soil temperature - 47 to 52 degrees F
Average summer soil temperature - 58 to 62 degrees F with an O horizon
Depth to weathered bedrock (lithic contact) - 8 to 20 inches
Thickness of the mollic epipedon - 7 to 11 inches
Base saturation (by NH4OAc) in all horizons between 1 to 14 inches - 60 to 80 percent
Base saturation (by sum) in all horizons between 1 to 14 inches - 35 to 45 percent
Particle-size control section - 5 to 15 percent clay and less than 25 percent fine sand and coarser in the fine-earth fraction, 40 to 85 percent rock fragments
Volcanic ash influence - 7 to 11 inches
Volcanic glass content - 5 to 15 percent
Acid-oxalate extractable Al + Fe - 0.40 to 1.0 percent
Moist bulk density, grams/cubic centimeter -1.0 to 1.2 g/cc (estimated)
Phosphate retention - 25 to 35 percent
A horizon
Hue - 10YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Texture - very gravelly ashy silt loam, gravelly ashy silt loam, ashy silt loam
Clay content - 4 to 14 percent
Gravel content - 5 to 45 percent
Cobble content - 0 to 15 percent
Channer content - 0 to 10 percent
Total rock fragment content - 5 to 55 percent
Reaction - slightly acid or neutral
AB horizon
Hue - 10YR or 7.5YR
Value - 5 dry, 3 moist
Chroma - 2 or 3, dry or moist
Texture - very gravelly ashy loam, very cobbly ashy silt loam, very gravelly ashy silt loam
Clay content - 5 to 15 percent
Gravel content - 35 to 55 percent
Paragravel content - 0 to 10 percent
Cobble content - 0 to 25 percent
Channer content - 0 to 20 percent
Flagstone content - 0 to 10 percent
Total rock fragment content - 35 to 55 percent
Reaction - moderately acid or slightly acid
AC horizon, present in some pedons
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - extremely cobbly ashy silt loam, extremely channery ashy silt loam, very cobbly ashy silt loam
Clay content - 5 to 15 percent
Gravel content - 15 to 30 percent
Paragravel content - 0 to 30 percent
Cobble content - 15 to 50 percent
Paracobble content - 0 to 30 percent
Channer content - 15 to 50 percent
Parachanner content - 0 to 30 percent
Flagstone content - 0 to 10 percent
Total rock fragment content - 45 to 80 percent
Reaction - moderately acid or slightly acid
Bw horizon, present in some pedons
C horizon
Hue - 10YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - extremely channery loam, extremely cobbly loam, extremely flaggy loam
Clay content - 7 to 17 percent
Gravel content - 20 to 45 percent
Paragravel content - 5 to 45 percent
Cobble content - 20 to 40 percent
Paracobble content - 0 to 30 percent
Channer content - 20 to 50 percent
Parachanner content - 0 to 35 percent
Flagstone content - 0 to 50 percent
Total rock fragment content - 65 to 85 percent
Reaction - moderately acid or slightly acid
COMPETING SERIES: This is the Rufus series. Rufus soils are on glaciated hillsides, they have a lithic contact, are dry for 75 to 90 consecutive days in the summer, do not have pararock fragments and C horizons, do not have ashy silt loam surface textures and have less than 35 percent rock fragments in the A1 horizon.
Similar soils with mixed mineralogy are the Borid, Brisky, Buckrock, Cox, Swakane and Witzel series. Borid soils do not have an influence of volcanic ash and formed in granitic parent materials. Brisky soils do not have an influence of volcanic ash and have sandy loam textures throughout. Buckrock (T) soils do not have an influence of volcanic ash, and have 25 to 50 percent medium and coarse sand in the particle-size control section. Cox soils do not have an influence of volcanic ash and have an aridic moisture regime. Swakane soils have in the particle-size control section 25 to 55 percent medium and coarse sand and a rock fragment content of 35 to 70 percent. Witzel soils formed in residuum and colluvium from basalt, have hues of 7.5YR or 5YR and more than 18 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Cassyhill soils are on summits and convex south-facing shoulders and back slopes of mountains and foothills. Slope ranges from 5 to 65 percent. They formed in residuum and colluvium weathered from metasedimentary bedrock, predominantly siltite and fine grained quartzite with an influence of loess and minor amounts of volcanic ash in the surface layers. Elevation ranges from 2,100 to 4,950 feet. The climate is warm and subhumid with warm, dry summers and cool, moist winters. The average annual air temperature is 46 to 50 degrees F. The average annual precipitation is 28 to 40 inches. The frost-free period is 100 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ardenvoir, Lotuspoint and Honeyjones soils. Ardenvoir soils are on east and west-facing back slopes of mountains, are deep to a paralithic contact, and have a frigid temperature regime. Lotuspoint soils are on similar landforms, are moderately deep to a lithic contact, and have a volcanic ash mantle less than 14 inches thick. Honeyjones soils are on north-facing back slopes of mountains, are very deep, and have a volcanic ash mantle greater than 14 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; runoff is medium to very rapid; permeability is moderate.
USE AND VEGETATION: These soils are used for timber production, grazing, wildlife habitat, recreation, and watershed. Potential natural overstory vegetation is mainly an open canopy of ponderosa pine with an understory of common snowberry, Idaho fescue, bluebunch wheatgrass, downy brome, common yarrow, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Northern Idaho and possibly eastern Washington and northwestern Montana; MLRA 43A. This soil is not extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon.
SERIES PROPOSED: Benewah County, Idaho, 2006. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 1 inch to 11 inches (A and AB horizons)
Lithic contact - the zone from 14 to 17 inches (R horizon)
Vitrandic feature - the zone from the mineral soil surface to 11 inches (A and AB horizons)
(Ninth Edition of Taxonomy does not currently recognize Lithic Ultic (Vitrandic) Haploxerolls.)
Particle-size control section - the zone from the mineral soil surface to 14 inches (A, AB and C horizons) with a weighted average of 47 percent rock fragments.
ADDITIONAL DATA: Partial laboratory data available for Soil Survey Sample Number: S04ID009-009, Benewah County, Idaho. NSSL Pedon Number: 05N0149