LOCATION TOLEX MT+CO
Established Series
Rev. JB/JAL/KLS
07/2022
TOLEX SERIES
The Tolex series consists of shallow, well drained soils that formed in material derived from igneous argillite, sandstone, and metasedimentary rock. These soils are on bedrock-floored hills and mountains. Slopes are 8 to 80 percent. The mean annual precipitation is about 410 mm and the mean annual air temperature is about 5 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haplustalfs
TYPICAL PEDON: Tolex channery loam, forest (colors are for dry soil unless otherwise noted).
Oe--0 to 3 cm; forest litter of partially decomposed needles, twigs and roots; clear smooth boundary. (1 to 5 cm thick)
A--3 to 6 cm; grayish brown (10YR 5/2) channery loam, very dark grayish brown (10YR 3/2) moist; moderate very thin platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and nonplastic; common fine and very fine roots; many very fine interstitial pores; 20 percent channers; moderately acid (pH 5.6); clear smooth boundary. (0 to 5 cm thick)
E--6 to 16 cm; very pale brown (10YR 7/3) channery loam, yellowish brown (10YR 5/4) moist; moderate very thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine and few medium roots; many very fine interstitial pores; gray silt and sand skeletans on faces of plates; 20 percent channers; moderately acid (pH 5.8); clear smooth boundary. (5 to 13 cm thick)
Bt--16 to 36 cm; light yellowish brown (10YR 6/4) extremely channery clay loam, yellowish brown (10YR 5/4) moist; moderate medium and fine subangular blocky structure; hard, friable, sticky and slightly plastic; common fine and very fine and few medium roots; many very fine tubular and interstitial pores; continuous distinct clay films on faces of peds and on coarse fragments; 65 percent channers; slightly acid (pH 6.2); gradual smooth boundary. (15 to 40 cm thick)
BC--36 to 49 cm; brownish yellow (10YR 6/6) extremely channery loam, yellowish brown (10YR 5/6) moist; weak very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; 85 percent channers, 5 percent flagstones; slightly effervescent on undersides of coarse fragments; neutral (pH 6.8) gradual wavy boundary. (0 to 15 cm thick)
R--49 cm; hard argillite bedrock with a few cracks; few fine roots in some cracks.
TYPE LOCATION: Lewis and Clark County, Montana; about 640 meters south and 60 meters east of the NW corner of sec. 34, T. l2 N., R. 3 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 8 degrees C
Moisture control section--10 to 30 cm
Depth to bedrock--25 to 50 cm
A horizon
Hue--5YR, 7.5YR, or 10YR
Value--5 or 6 dry; 3 or 4 moist
Chroma--2 or 3
Texture--loam or sandy loam
Clay content--15 to 25 percent
Rock fragment content--15 to 75 percent; 0 to 20 percent flagstones and stones, 15 to 55 percent channers
Reaction--pH 5.6 to 7.3
E horizon
Hue--5YR, 7.5YR, or 10YR
Value--5 through 7 dry; 4 or 5 moist
Chroma--2 through 4
Texture--loam, sandy loam or coarse sandy loam
Clay content--10 to 25 percent
Rock fragment content--15 to 75 percent; 0 to 15 percent flagstones, 15 to 60 percent channers
Reaction--pH 5.1 to 7.3
Bt horizon
Hue--5YR, 7.5YR, or 10YR
Value--5 or 6 dry; 4 or 5 moist
Chroma--3, 4, or 6
Texture--clay loam, sandy clay loam or sandy loam
Clay content--18 to 35 percent
Rock fragment content--60 to 80 percent; 0 to 15 percent flagstones, 40 to 70 percent channers
Reaction--pH 5.1 to 7.8
BC horizon
Hue--5YR, 7.5YR, or 10YR
Value--6 or 7 dry; 4 or 5 moist
Chroma--3, 4, or 6
Clay content--10 to 25 percent
Rock fragment content--60 to 90 percent; 0 to 10 percent flagstones, 55 to 85 percent channers
Reaction--pH 5.1 to 7.8
COMPETING SERIES:
Brickner (MT) - have less than 60 percent rock fragments in the particle-size control section
Sanchez (NM) - have less than 60 percent rock fragments in the particle-size control section
GEOGRAPHIC SETTING:
Landform--bedrock-floored hills, mountains
Elevation--1075 to 1900 meters (Colorado has elevations of 2275 to 2750 meters)
Slope--8 to 80 percent
Parent material--igneous argillite, sandstone, and metasedimentary rock
Climate--long, cold winters; moist springs and early part of summer; warm summers
Mean annual precipitation--310 to 640 mm, most of which falls during the spring and early part of summer
Mean annual air temperature--3 to 7 degrees C
Frost-free period--70 to 120 days (Colorado has a frost-free period of 75 to 140 days)
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Well drained; moderate or moderately slow permeability
USE AND VEGETATION: Tolex soils are used for range and woodland. The native vegetation is mainly ponderosa pine, Douglas fir, bluebunch wheatgrass, Idaho fescue, rough fescue, arrowleaf balsamroot, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Tolex soils are moderately extensive in the mountainous regions of western Montana and southcentral Colorado; MLRAs 43B, 44B and 49
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fremont County, Colorado, 1988; proposed in Lewis and Clark County, Montana, 1979
REMARKS: Diagnostic horizons and features recognized in this pedon are:
O horizon--0 to 3 cm (Oi horizon)
Ochric epipedon--3 to 16 cm, mixed (A, E horizons)
Argillic horizon--16 to 36 cm (Bt horizon)
Lithic contact--49 cm to bedrock (R horizon)
Particle-size control section--16 to 36 cm (Bt horizon)
Tolex soils have a frigid temperature regime and an ustic soil moisture regime.
Classification changed from Lithic Eutroboralfs in 1997
Converted to metric, updated formatting, and O horizons were updated to start at zero. 7/2022
Soil interpretation records: MT0386, MT1010
National Cooperative Soil Survey
U.S.A.