LOCATION LOKEN MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Loken silty clay loam, grassland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 6 inches; very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; moderate medium and fine subangular blocky structure parting to strong fine granular; hard, very friable, moderately sticky and moderately plastic; many fine and very fine roots and pores; 5 percent pebbles; neutral (pH 7.2); abrupt wavy boundary. (4 to 8 inches thick)
Bw--6 to 11 inches; brown (10YR 5/3) silty clay loam, very dark brown (10YR 2/2) moist; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; very hard, friable, moderately sticky and moderately plastic; many fine and very fine roots and pores; 5 percent pebbles; slightly alkaline (pH 7.4); clear irregular boundary. (4 to 8 inches thick)
Bk1--11 to 15 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to moderate fine subangular blocky; very hard, very friable, moderately sticky and moderately plastic; many fine and very fine roots and pores; 10 percent pebbles; common fine threads of lime; strongly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 7 inches thick)
Bk2--15 to 27 inches; light gray (10YR 7/2) gravelly clay loam, pale brown (10YR 6/3) moist; weak medium and coarse prismatic structure parting to weak fine subangular blocky; very hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; many fine and very fine pores; 25 percent pebbles; common medium and fine soft masses of lime; violently effervescent; moderately alkaline (pH 8.2); diffuse wavy boundary. (10 to 20 inches thick)
Bk3--27 to 60 inches; light gray (10YR 7/2) gravelly clay loam, pale brown (10YR 6/3) moist; weak fine subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; few fine and very fine roots in upper part of horizon grading to none in lower part; common fine and very fine pores in upper part grading to few very fine pores in the lower part; 25 percent pebbles; 5 percent cobbles; common medium and fine soft masses of lime throughout profile; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Fergus County, Montana; about 100 meters north and 550 meters east of the SW corner of sec. 1, T. 17 N., R. 17 E.
RANGE IN CHARACTERISTICS:
Soil temperature: 42 to 45 degrees F.
Mollic epipedon thickness: 7 to 15 inches
Rock fragments: mainly limestone
Depth to k horizon: 6 to 15 inches
Ap horizon:
Hue: 10YR
Value, dry: 3 or 4
Value, moist: 2
Chroma: 1 or 2
Texture: silty clay loam or clay loam
Clay content: 30 to 40 percent
Rock fragments: 5 to 35 percent
Stones: 0 to 10 percent
Cobbles: 0 to 15 percent
Pebbles: 5 to 10 percent
Reaction: pH 6.1 to 7.3
Bw horizon:
Hue: 10YR
Value, dry: 4 or 5
Value, moist: 2 or 3
Chroma: 2 or 3
Texture: silty clay loam, clay loam, or clay
Clay content: 35 to 50 percent
Rock fragments: 5 to 15 percent
Cobbles: 0 to 5 percent
Pebbles: 5 to 10 percent
Reaction: pH 6.6 to 7.8
Bk1 horizon:
Hue: 10YR
Value, dry: 5 or 6
Value, moist: 4 or 5
Chroma: 2 or 3
Texture: clay loam or clay
Clay content: 35 to 50 percent
Rock fragments: 5 to 15 percent
Cobbles: 0 to 5 percent
Pebbles: 5 to 10 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
Bk2 and Bk3 horizons:
Hue: 10YR or 2.5Y
Value, dry: 6 or 7
Value, moist: 4, 5, or 6
Chroma: 2, 3, or 4
Texture: clay loam or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 35 percent
Stones: 0 to 5 percent
Cobbles: 0 to 5 percent
Pebbles: 0 to 25 percent
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES: These are the Litimber and Timberg series. Litimber soils have hue of 5YR or 2.5YR below the A horizon. Timberg soils are moderately deep to a paralithic contact.
GEOGRAPHIC SETTING: Loken soils are on uplands, fans, and mountain slopes and have slope gradients of 2 to 45 percent. Elevations are 4,000 to 5,000 feet. Loken soils formed in clayey alluvium and residuum derived from lime- stone and calcareous shale. The climate is cool with long cold winters and moist springs and summers. Mean annual temperature is 40 to 43 degrees F. Average annual precipitation is 19 to 24 inches, most of which falls during spring and early summer. The growing season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brazon, Judith, Maiden, Windham, and Winifred series. The Brazon soils are clayey-skeletal. The Judith, Maiden, and Windham soils contain less than 35 percent clay in the particle-size control sections. The Winifred soils are moderately deep over shale.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Used mainly for rangeland. To a lesser extent these soils are used for cropland and pasture. Native vegetation is mainly rough fescue, bluebunch wheatgrass, green needlegrass, western wheatgrass, Idaho fescue, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Loken soils are inextensive in the foothills area of central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fergus County, Montana, 1979.