LOCATION MCCROSKET ID+WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerolls
TYPICAL PEDON: McCrosket gravelly ashy silt loam, forested; on a southwest-facing slope of 54 percent at 3,760 feet elevation. Pedon was described on September 5, 2000 and was dry throughout. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; undecomposed needles and twigs. (0 to 1.5 inches thick)
Oe--1 to 1.5 inches; partially decomposed needles and twigs mixed with 1980 Mt. St. Helens volcanic ash. (0 to 2 inches thick)
A1--1.5 to 5 inches; dark grayish brown (10YR 4/2) gravelly ashy silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine and common medium roots; many very fine, fine and common medium tubular pores; 25 percent gravel; slightly acid (pH 6.5); gradual wavy boundary.
A2--5 to 12 inches; brown (10YR 5/3) gravelly ashy silt loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many very fine, fine and common medium roots; many very fine, fine and common medium tubular pores; 30 percent gravel; neutral (pH 6.8); clear wavy boundary. (Combined thickness of A horizons is 5 to 20 inches thick)
Bw1--12 to 20 inches; light brown (7.5YR 6/3) very cobbly silt loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and few medium roots; common very fine and few fine and medium tubular pores; 25 percent gravel, 30 percent cobbles; moderately acid (pH 6.0); gradual wavy boundary.
Bw2--20 to 32 inches; light brown (7.5YR 6/3) very cobbly silt loam, brown (7.5YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and common medium and coarse roots; common very fine and few fine and medium tubular pores; 20 percent gravel, 35 percent cobbles; moderately acid (pH 5.7); gradual wavy boundary. (combined thickness of Bw horizons is 20 to 30 inches thick)
BC--32 to 42 inches; pink (7.5YR 7/3) extremely cobbly loam, brown (7.5YR 5/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine and medium roots; common very fine and few fine tubular pores; 15 percent gravel, 45 percent cobbles; moderately acid (pH 5.9); abrupt wavy boundary. (BC horizon 0 to 20 inches thick)
Cr--42 inches; fractured, weathered siltite.
TYPE LOCATION: Benewah County, Idaho; about 0.5 miles northwest of Windfall Pass about 1900 feet south and 2000 feet west of the northeast corner, sec. 16 T.45N., R.4W. Latitude - 47 degrees, 14 minutes, 43 seconds North; Longitude - 116 degrees, 50 minutes, 26 seconds West; NAD 83; USGS Benewah quadrangle.
RANGE IN CHARACTERISTICS:
Depth to bedrock - 40 to 60 inches from mineral soil surface.
Moisture control section - usually dry for 45 to 75 days from July to mid-September; moist mid-September through June
Average annual soil temperature - 45 to 50 degrees F.
Average summer soil temperature - 54 to 58 degrees F. with an O horizon.
Mollic epipedon thickness - 10 to 17 inches.
Volcanic ash influence - 7 to 12 inches thick
Moist bulk density - 1.0 to 1.2 g/cc (estimated)
Volcanic glass content - 5 to 20 percent (estimated)
Acid-oxalate extractable Al + Fe - 0.4 to 0.7 percent (estimated)
Phosphate retention - 25 to 50 percent (estimated)
A horizons
Hue - 10YR or 7.5YR, dry and moist
Value - 3 to 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry, 1 to 3 moist
Texture - ashy silt loam, ashy loam
Clay content - 5 to 18 percent
Gravel content - 15 5 to 30 percent
Cobble content - 0 to 15 percent
Total rock fragment content - 5 to 30 percent
Reaction - moderately acid to neutral
Bw horizons
Hue - 7.5YR or 10YR, dry or moist
Value - 4 to 7 dry, 3 to 6 moist
Chroma - 3 to 6, dry or moist
Textures - silt loam, loam
Clay content - 10 to 25 percent
Gravel content - 20 to 50 percent
Cobble content - 15 to 50 percent cobbles
Stone content - 0 to 15 percent stones
Total rock fragment content - 35 to 70 percent
Reaction - strongly acid to slightly acid
BC and C horizons (when present)
Hue - 7.5YR or 10YR, dry or moist
Value - 6 to 8 dry, 4 to 6 moist
Chroma - 3 to 6, dry or moist
Texture - loam, sandy loam
Clay content - 5 to 25 percent
Gravel content - 10 to 50 percent
Cobble content - 5 to 50 percent
Stone content - 0 to 15 percent
Total rock fragment content - 35 to 80 percent
Reaction - strongly acid to moderately acid
COMPETING SERIES:
Bearspring - are very deep (greater than 60 inches).
Bigelk - are very deep (greater than 60 inches).
Cassal - are deep (40 to 60 inches) to densic contact and have distinct redoximorphic features at 30 to 45 inches.
Cherrycreek - are deep (40 to 60 inches) to a lithic contact and mollic epipedon is 20 to 35 inches thick.
Deck - are moderately deep (20 to 40 inches) to a lithic contact.
Eastpine - are moderately deep (20 to 40 inches) to a lithic contact.
Egyptcreek - are moderately deep (20 to 40 inches) to a lithic contact.
Fredonyer - are moderately deep (20 to 40 inches) to a lithic contact and mollic epipedon is 20 to 40 inches thick.
Golfer - are moderately deep (20 to 40 inches) to a paralithic contact.
Grubcreek - are moderately deep (20 to 40 inches) to a lithic contact.
Kettlecreek - are deep (40 to 60 inches) to a lithic contact.
Longs - are deep (40 to 60 inches) to a lithic contact and mollic epipedon is 20 to 45 inches thick.
Midpeak - are moderately deep (20 to 40 inches) to a lithic contact.
Mineral - are moderately deep (20 to 40 inches) to a lithic contact.
Peahke - are moderately deep (20 to 40 inches) to a paralithic contact
Piersonte - are very deep (greater than 60 inches) and mollic epipedon is 20 to 35 inches thick.
Porch - are moderately deep (20 to 40 inches) to lithic contact.
Scoap - are very deep (greater than 60 inches) and mollic epipedon is 20 to 30 inches thick.
Shalrock - are moderately deep (20 to 40 inches) to a lithic contact.
Shilling - are very deep (greater than 60 inches).
Umatilla - are very deep (greater than 60 inches) and mollic epipedon is 20 to 30 inches thick.
Webbgulch - are moderately deep (20 to 40 inches) to a lithic contact.
Yellcreek - are very deep (greater than 60 inches).
GEOGRAPHIC SETTING: McCrosket soils are on mountains and footslopes. They occupy northerly aspects at lower elevations, and they occupy southerly aspects and ridgetops at higher elevations. Slopes range from 5 percent to 65 percent. They formed in residuum and colluvium weathered from metasedimentary bedrock, predominantly siltite and fine grained quartzite with a mantle of loess mixed with minor amounts of volcanic ash. Elevations range from 2200 to 4000 feet. The average annual precipitation ranges from 18 to 35 inches. The average annual air temperature ranges from 45 to 49 degrees F. The frost-free period is from 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ardenvoir, Huckle, Tekoa, and Rasser soils. Ardenvoir soils have an ochric epipedon and occupy all aspects of adjacent mountains and foothills. Huckle soils have thick volcanic ash mantles and occupy northerly aspects on adjacent mountains and foothills. Tekoa soils have an argillic horizon, are moderately deep, and occupy convex positions on southerly aspects. Rasser soils are very deep, have an ochric epipedon, and occupy easterly aspects on linear positions of adjacent foothills and mountains.
DRAINAGE AND PERMEABILITY: Well-drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for timber production with limited grazing. Potential natural overstory vegetation is mainly Douglas-fir, ponderosa pine with an understory of creambush oceanspray, mallow ninebark, common snowberry, spirea, rose and pinegrass.
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington. MLRA 43A and 9. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Benewah County, Idaho, 1975.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
Mollic epipedon - the zone from 1.5 to 12 inches (A1 and A2 horizons)
Cambic horizon - the zone from 12 to 32 inches (Bw1 and Bw2 horizons)
Vitrandic feature - the zone from 1.5 to 12 inches (A1 and A2 horizons)
Particle-size control section - the zone from 11.5 to 41.5 inches (part of the A2 horizon, the Bw1, Bw2, and part of the BC horizon)
Paralithic contact - 42 inches (Cr horizon)
The McCrosket soils have a xeric soil moisture regime and a frigid soil temperature regime.
Classification revised 2/2009 from loamy-skeletal, mixed, active, mesic Ultic Haploxerolls to loamy-skeletal, isotic, frigid Vitrandic Haploxerolls based on MLRA 43A investigations in Benewah County Area, Idaho (ID620), Latah County, Idaho (ID057), and Spokane County, Washington (WA075). Type location was moved to present location in 2007 to better reflect modal concept.