LOCATION POHLOD MT
Tentative Series
IRD. KTS-EMM
02/2014
POHLOD SERIES
The Pohlod series consists of moderately deep, well drained soils that formed in colluvium over residuum from mixed igneous rock sources. These soils occur on mountain slopes. Slopes are 15 to 60 percent. Mean annual precipitation is about 700 mm, and the mean annual temperature is about 3 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Typic Argicryolls
TYPICAL PEDON: Pohlod gravelly loam, in forest on a 20 percent slope at an elevation of 1560 meters (Colors are for dry soil unless otherwise noted).
Oi -- 0 to 4 cm; slightly decomposed forest litter; clear smooth boundary. (3 to 5 cm thick)
A--4 to 16 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, medium, and coarse roots; few very fine and fine irregular pores; 25 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (8 to 15 cm thick)
Bt1--16 to 40 cm; dark grayish brown (2.5Y 4/2) very gravelly clay loam, very dark grayish brown (2.5Y 3/2) moist; weak medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine, fine, medium, and coarse roots; few very fine and fine tubular pores; few (10 percent) faint clay films on faces of peds; 35 percent gravel and 2 percent cobbles; moderately acid (pH 5.8); clear wavy boundary.
Bt2--40 to 61 cm; light olive brown (2.5Y 5/3) very gravelly sandy clay loam, olive brown (2.5Y 4/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine, fine, medium, and coarse roots; few very fine and fine tubular pores; few (20 percent) faint clay films on faces of peds; 35 percent gravel and 5 percent cobbles; moderately acid (pH 5.6); gradual wavy boundary. (combined thickness of Bt horizons - 20 to 80 cm)
BC--61 to 73 cm light grayish brown (2.5Y 5/2) very gravelly sandy clay loam, dark grayish brown (2.5Y 4/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; few very fine and fine tubular pores; 50 percent gravel and 5 percent cobbles; moderately acid (pH 5.6); abrupt wavy boundary. (0 to 40 cm thick)
R--73 to 150 cm; hard igneous bedrock.
TYPE LOCATION: Chouteau County, Montana; located 657 meters east and 270 meters north of the southwest corner of sec. 16, T.20N., R9E.; Arrow Peak topographic quadrangle; UTM 12T, 0530973e., 5259814n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1 to 4 degrees C.
Thickness of mollic epipedon - 25 to 40 cm
A horizon
Value: 2, 3 or 4; dry or moist
Chroma: 2 or 3; dry or moist
Clay content: 18 to 26 percent
Rock fragments: 5 to 35 percent-5 to 30 percent gravel, 0 to 10 percent cobbles
Reaction: pH 5.6 to 6.4
Bt horizons
Hue: 10YR or 2.5Y
Value: 3, 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: clay loam or sandy clay loam
Clay content: 25 to 35 percent
Rock fragments: 20 to 60 percent-15 to 45 percent gravel, 0 to 30 percent cobbles
Reaction: pH 5.6 to 6.4
BC horizon
Hue: 10YR or 2.5Y
Value: 4 to 6 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam or sandy clay loam
Clay content: 12 to 22 percent
Rock fragments: 35 to 85 percent-35 to 70 percent gravel, 5 to 30 percent cobbles
Reaction: pH 5.6 to 6.4
COMPETING SERIES:
Elkpeak (MT) - is very deep
Elwood (UT) - has a frost free season of 75 to 90 days and occurs on elevations above 2280 meters.
Ezbin (ID) - is very deep
Quazar (CO) - is very deep
Tahquats (ID) - is very deep
Wander (CO) - is very deep
GEOGRAPHIC SETTING:
Landform - mountain slopes. Elevation - 1370 to 2100 meters.
Slope - 15 to 60 percent.
Parent material - colluvium from mixed igneous rock sources.
Climate - long, cold winters; moist springs; short warm summers.
Mean annual precipitation - 610 to 830 mm.
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 40 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: well drained, moderate permeability.
USE AND VEGETATION: Pohlod soils are used mainly for timber, wildlife and recreation. The vegetation is mainly Douglas-fir, lodgepole pine, quaking aspen, twinflower, spirea, huckleberry, common juniper, snowberry, Oregon grape, arnica (species), pinegrass, elksedge and other miscellaneous shrubs, grasses and forbs.
DISTRIBUTION AND EXTENT: Pohlod soils are of small extent in central Montana. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Chouteau County, Montana, 2013. Pohlod series is named for a drainage on the Arrow Peak topographic quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 4 to 40 cm (A and Bt1 horizons)
Argillic horizon - from 16 to 61 cm (Bt1 and Bt2 horizons)
Particle-size control section - from 16 to 61 cm (Bt1 and Bt2 horizons)
Pohlod soils have a cryic temperature regime and a udic moisture regime.
Taxonomic version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.