LOCATION LOLO MT
Established Series
Rev. CAM-SHB-EMM
04/2013
LOLO SERIES
The Lolo series consists of very deep, well drained soils that formed in gravelly alluvium derived from mixed rock sources. Lolo soils are on stream terraces and drainageways. Slopes are 0 to 10 percent. The mean annual precipitation is about 400 mm, and the mean annual air temperature is about 6.5 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Lolo gravelly loam, cultivated. (colors are for dry soil unless otherwise noted.)
A1--0 to 28 cm; dark gray (10YR 4/1) gravelly loam; black (10YR 2/1) moist; moderate fine granular structure; soft, friable, slightly sticky and slightly plastic; many fine roots and pores; 15 percent gravel mainly of argillite and quartzite; neutral (pH 7.0); gradual smooth boundary.
A2--28 to 46 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR 2/2) moist; weak medium blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine and medium pores; 15 percent gravel; neutral (pH 7.2); clear smooth boundary. (combined thickness of A horizons - 40 to 66 cm)
Bw--46 to 96 cm; yellowish brown (10YR 5/4) very gravelly loam, dark yellowish brown (10YR 3/4) moist; moderate very fine blocky structure; soft, friable, slightly sticky and slightly plastic; many fine roots; many fine pores; 55 percent gravel and 5 percent cobbles; neutral (pH 7.2); gradual smooth boundary. (15 to 50 cm thick)
C--96 to 152 cm; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and nonplastic; common roots; 65 percent gravel and 10 percent cobbles; neutral (pH 7.2).
TYPE LOCATION: Ravalli County, Montana; 385 meters south and 35 meters east of NW corner of section 8, T.10N, R.19W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 4.5 to 8.0 degrees C.
Mollic epipedon thickness - 40 to 66 cm
A horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2; dry or moist
Texture: loam or sandy loam
Clay content: 15 to 25 percent
Rock fragments: 15 to 60 percent--15 to 45 percent gravel, 0 to 25 percent cobbles
Reaction: pH 6.6 to 7.8
Bw horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or sandy loam
Clay content: 15 to 25 percent
Rock fragments: 45 to 80 percent--30 to 70 percent gravel, 0 to 50 percent cobbles
Reaction: pH 6.6 to 7.8
C horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or sandy loam
Clay content: 10 to 25 percent
Rock fragments: 50 to 80 percent--30 to 70 percent gravel, 0 to 50 percent cobbles
Reaction: pH 6.6 to 7.8
Some pedons do not have a C horizon.
COMPETING SERIES:
Alchonzo (NM) - moderately deep to a lithic contact
Blanca (NM) - are dry in April,
May and June
Caballo (NM) - are dry in April,
May and June
Garber (CO) - do not have a cambic horizon
Hidatsa (ND) - have a lithologic discontinuity
Mescalero (NM) - moderately deep to a lithic contact
Osha (NM) - deep to a lithic contact
Utso (UT) - deep to a lithic contact
GEOGRAPHIC SETTING:
Landform - stream terraces and drainageways
Elevation - 915 to 1,525 meters
Slope - 0 to 10 percent
Parent material - gravelly alluvium derived from mixed rock sources
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 305 to 500 mm
Mean annual air temperature - 4.5 to 7.0 degrees C.
Frost-free period - 70 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Used for dryland and irrigated cropland; the major crops are small grains, hay and pasture. Some areas are used for range. Principal native vegetation is western wheatgrass, bluebunch wheatgrass needleandthread, prairie junegrass, Sandburg bluegrass, prairie sandreed, and forbs and shrubs. Some areas have low-density stands of ponderosa pine.
DISTRIBUTION AND EXTENT: In western and central Montana. MLRAs - 43B, 44B, 46, 48A, 51, 52, 58A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 1914.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - 0 to 46 cm (A1, A2 horizons)
cambic horizon - 46 to 96 cm (Bw horizon)
particle-size control section - 25 to 100 cm (part of A1, A2, Bw, part of C horizons).
Lolo soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.