LOCATION CRADDOCK MTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Andic Haplocryepts
TYPICAL PEDON: Craddock channery silt loam, forested. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; needles, grass, leaves, and moss.
E--1 to 2 inches; light gray (10YR 7/1) channery loam, gray (10YR 6/1) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, and medium roots, many pores; 20 percent hard shale channers, 5 percent soft shale fragments; moderately acid (pH 5.6). (0 to 2 inches thick)
Bw--2 to 10 inches; light yellowish brown (10YR 6/4) channery silt loam, dark yellowish brown (10YR 4/4) moist, with some color variegations (15 percent) of both lighter and darker colored material; weak medium and fine subangular blocky structure parting to weak very fine granular; soft, very friable, nonsticky and nonplastic; many fine and medium roots; many fine tubular and interstitial pores; 20 percent hard shale channers; 10 percent soft shale fragments; moderately acid (pH 6.0); clear wavy boundary. (7 to 14 inches thick)
2E1--10 to 20 inches; very pale brown (10YR 8/2) channery loam, light brownish gray (10YR 6/2) moist; weak medium and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine and medium roots; common medium and fine tubular pores; 30 percent hard shale channers; 25 percent soft shale fragments; moderately acid (pH 5.7) gradual wavy boundary.
2E/Bw1--20 to 26 inches; E part (90 percent) pale yellow (2.5Y 8/2) channery loam, light brownish gray (2.5Y 6/2) moist; B part (10 percent) very pale brown (10YR 7/4) channery loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine, medium and very coarse roots; common medium and fine interstitial and few fine tubular pores; 30 percent hard shale channers, 30 percent soft shale fragments; few faint clay films on surface of fragments, in pores, and on concave faces of peds; moderately acid (pH 5.7); gradual wavy boundary. (The combined thickness of the 2E horizon is 6 to 29 inches.)
2E/Bw2--26 to 46 inches; E part (65 percent) light gray (5Y 7/2) channery loam, olive gray (5Y 5/2) moist; B part (35 percent) very pale brown (10YR 7/4) channery loam, light yellowish brown (10YR 6/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine, medium and very coarse roots; common medium and fine interstitial and few fine tubular pores; few faint clay films on faces of peds, in pores and in root channels; 30 percent hard shale channers, 30 percent soft shale fragments; moderately acid (pH 5.7); gradual wavy boundary. (10 to 28 inches thick)
2Cr--46 to 60 inches; gray and brown shale; moderately acid (pH 6.0).
TYPE LOCATION: Mineral County, Montana; 10 miles from cutoff road on Tamarack Creek Road, in unsectionized area. Aerial photo EDS10-55 on line 40.
RANGE IN CHARACTERISTICS:
Soil temperature - 39 to 44 degrees F.
Moisture control section - approximately between the depths of 8 and 24 inches.
Control section - 5 to 10 percent clay and 40 to 75 percent silt and very fine sand.
Depth to 2Cr - 40 inches and deeper.
Soil phases - loamy substratum
E horizon - Hue: 10YR or 7.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: loam or silt loam
Clay content: 5 to 10 percent
Rock fragments: 0 to 55 percent--0 to 20 percent hard shale channers; 0 to 25 percent soft shale fragments
Reaction: pH 5.6 to 6.5
Bw horizon - Hue: 10YR or 7.5YR
Value: 5 or 6 dry; 4 to 5 moist
Chroma: 4 or 6
Texture: silt loam or loam
Clay content: 5 to 10 percent
Rock fragments: 0 to 55 percent--0 to 20 percent hard shale channers; 0 to 25 percent soft shale fragments
Bulk density: 1.0 grams per cubic centimeter or less
Reaction: pH 5.6 to 6.5
2E horizon - Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 4, 5 or 6 moist
Chroma: 2, 3, or 4
Texture: silt loam or loam
Clay content: 5 to 10 percent
Rock fragments: 15 to 60 percent--0 to 35 percent hard shale channers and flagstones; 10 to 25 percent are soft shale fragments
Reaction: pH 5.6 to 6.5
2E/Bw horizons - Hue: E part 10YR or 2.5Y; B part 10YR or 7.5Y
Value: E part 6 or 7, B part 5 or 6 dry; E part 4, 5 or 6, B part 4 or 5 moist
Chroma: E part 2, 3, or 4; B part 3 or 4
Texture: silt loam or loam
Clay content: 5 to 10 percent
Rock fragments: 15 to 60 percent--5 to 35 percent hard shale channers and flagstones; 10 to 25 percent soft shale fragments
Reaction: pH 5.6 to 6.5
COMPETING SERIES:
Blackburn (MT) - has mixed A/B horizon immediately below the low bulk density ash influenced layer; does not have soft shale fragments in the profile.
GEOGRAPHIC SETTING:
Landform- mountains.
Elevation - 3,000 to 6,400 feet.
Slope - 4 to 65 percent.
Parent material - colluvium derived from soft, thinly bedded weathered argillites of the Belt series.
Climate - long, cold winters, moist springs, cool summers.
Mean annual precipitation - 30 to 60 inches.
Mean annual temperature - 37 to 42 degrees F.
Frost-free period - 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; moderately rapid permeability.
USE AND VEGETATION: Craddock soils are used mainly for timber production, watersheds, and as wildlife habitat. Potential native vegetation is subalpine fir, Engelmann spruce, Douglas-fir, western larch, grand fir, white fir, white pine, and lodgepole pine with an understory of mallow ninebark, pinegrass, blue huckleberry, rusty menziesia, and common beargrass.
DISTRIBUTION AND EXTENT: Craddock soils are moderately extensive in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Mineral County (St. Regis-Ninemile Area), Montana, 1970.
REMARKS: Soil Interpretations Records: MT0650, MT1114. Diagnostic horizons and features recognized in this pedon are: a soil layer from the mineral soil surface to 10 inches that has a moist bulk density of 1.0 grams per cubic centimeter or less (Bw horizon); an albic horizon from 10 to 26 inches (2E1 and 2E2 horizons); a cambic horizon from 26 to 46 inches (2E/Bw horizon); and a particle-size control section form 10 to 40 inches (2E1, 2E2, and 2E/Bw horizons). Craddock soils have a cryic temperature regime and a udic moisture regime. The Craddock soils meet the requirements for the Andic subgroup and it is assumed that the acid-oxalate is less than 1.0.
ADDITIONAL DATA: Montana S-64-MONT-31-4 Lincoln, Nebraska.
The 3/2008 description reflects a change in classification from Coarse-loamy, mixed, superactive Andic Eutrocryepts to Coarse-loamy, mixed, superactive Andic Haplocryepts due to revision of the cryepts great groups and subgroups. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified.