LOCATION HOYT MT
Established Series
Rev. BDD-DES-KLS
01/2023
HOYT SERIES
The Hoyt series consists of very deep, well drained soils that formed in colluvium and slope alluvium derived from igneous bedrock and glacial till. These soils are on mountains, moraines, hills and alluvial fans. Slopes are 4 to 60 percent. Mean annual precipitation is about 560 mm, and mean annual air temperature is about 4 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Hoyt loam, 8 to 15 percent slopes, in woodland (colors are for dry soil unless otherwise noted).
Oe--0 to 3 cm; partially decomposed twigs and needles.
A1--3 to 18 cm; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and medium roots; common very fine irregular pores; 10 percent pebbles; neutral (pH 7.2); clear smooth boundary. (8 to 20 cm)
A2--18 to 33 cm; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and medium roots; many very fine tubular pores; common skeletans of light brownish gray (10YR 6/2) unstained sand and silt grains; 15 percent pebbles; neutral (pH 7.0); clear wavy boundary. (0 to 15 cm thick)
Bt1--33 to 61 cm; yellowish brown (10YR 5/4) gravelly sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; many very fine tubular pores; common faint dark yellowish brown (10YR 4/4) clay films on faces of peds; 15 percent pebbles; 5 percent cobbles; neutral (pH 7.2); clear wavy boundary.
Bt2--61 to 97 cm; light olive brown (2.5Y 5/4) gravelly sandy clay loam, olive brown (2.5Y 4/4) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and few medium roots; many very fine tubular pores; common distinct dark yellowish brown (10YR 4/4) clay films on faces of peds; 15 percent pebbles; 5 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (Combined thickness of Bt1 and Bt2 horizons - 45 to 85 cm thick)
BC--97 to 155 cm; light olive brown (2.5Y 5/4) gravelly coarse sandy loam, olive brown (2.5Y 4/4) moist; massive; soft, friable, moderately sticky and nonplastic; few fine and medium roots; 15 percent pebbles; 5 percent cobbles; common very fine irregular pores; slightly alkaline (pH 7.6).
TYPE LOCATION: Powell County, Montana; about 455 meters east and 855 meters south of the NW corner of sec. 2, T. 10 N., R. 11 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 8 degrees C
Soil moisture control section--between 10 and 30 cm
The soils are frozen in the moisture control section and deeper from approximately November through the end of March.
They are moist in some or all parts of the moisture control section from April through mid-July.
The surface when mixed to 18 cm has mollic colors but does not meet the thickness requirements for a mollic epipedon.
A1 horizon
Value--4 or 5 dry; 2 or 3 moist
Chroma--2 or 3
Clay content--18 to 27 percent
Rock fragment content--0 to 15 percent total; 0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction--pH 5.6 to 7.8
A2 horizon
Value--2 to 4 moist
Chroma--2 or 3
Clay content--10 to 27 percent
Rock fragment content--0 to 20 percent total; 0 to 5 percent cobbles, 0 to 15 percent pebbles
Reaction--pH 6.6 to 7.8
Bt1 horizon
Hue--10YR, 2.5Y, or 7.5YR
Value--4 to 6 dry; 3 or 4 moist
Chroma--3 or 4
Texture--clay loam, sandy clay loam, loam
Clay content--18 to 35 percent
Rock fragment content--10 to 35 percent--0 to 5 percent cobbles, 10 to 30 percent pebbles
Reaction--pH 6.1 to 7.8
Bt2 horizon
Hue--10YR, 2.5Y, or 7.5YR
Value--4 or 5 dry; 3 or 4 moist
Texture--clay loam, sandy clay loam, loam
Clay content--18 to 35 percent
Rock fragment content--15 to 35 percent total; 0 to 5 percent cobbles, 15 to 30 percent pebbles
Reaction--pH 6.1 to 7.8
BC horizon
Hue--2.5Y or 10YR
Value--5 or 6 dry; 4 or 5 moist
Chroma--2, 3, or 4
Texture--coarse loamy sand, coarse sandy loam, clay loam
Clay content--10 to 30 percent
Rock fragment content--15 to 35 percent total; 0 to 5 percent cobbles, 15 to 30 percent pebbles
Reaction--pH 6.6 to 7.8
COMPETING SERIES:
Elbeth (CO) - have an albic horizon
Elmark (MT) - have a paralithic contact at 50 to 100 cm and a lithic contact at 100 to 150 cm
Jemco (CO) - have a lithic contact at 50 to 100 cm
Lumpgulch (MT) - have a paralithic contact at 50 to 100 cm and a lithic contact at 60 to 100 cm
Northrim (CO) - are drier in spring; formed in colluvium or slope alluvium from sandstone and shale
Shoemaker (NM) - have a lithic contact at 50 to 100 cm
Sweetweed (MT) - have a glossic horizon
Zunalei (NM) - have less than 5 percent rock fragments in the particle-size control section
GEOGRAPHIC SETTING:
Landform--mountains, hills, moraines and alluvial fans
Elevation--1350 to 1975 meters
Slope--4 to 60 percent
Parent material--colluvium derived from igneous bedrock and glacial till
Climate--long, cold winters; moist springs; and warm summers
Mean annual precipitation--380 to 610 mm
Mean annual air temperature--2 to 7 degrees C
Frost-free period--70 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability
USE AND VEGETATION: Hoyt soils are used for timber production, watersheds, and as wildlife habitat. The potential native vegetation is Douglas-fir, ponderosa pine, and lodgepole pine with an understory of pinegrass, common snowberry, elk sedge, and Oregon grape.
DISTRIBUTION AND EXTENT: Hoyt soils are of small extent in the mountains of western Montana and northwestern Wyoming; MLRA 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Powell County, Montana, 1995
REMARKS: Soil interpretation record: MT1298
Diagnostic horizons and features recognized in this pedon are:
Mollic colors--3 to 18 cm (A1 horizon)
Argillic horizon--33 to 97 cm (Bt1, Bt2 horizons)
Particle size control section--33 to 83 cm (Bt1 and part of Bt2 horizon)
Hoyt soils have a frigid soil temperature regime and an ustic soil moisture regime with a typic subclass.
Classification changed from Mollic Eutroboralfs in 1997.
Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 01/2023
National Cooperative Soil Survey
U.S.A.