LOCATION KNEP MT
Established Series
Rev. EW-KTS-RJS
05/2017
KNEP SERIES
The Knep series consists of moderately deep, well drained soils that formed in slope alluvium, colluvium or slide deposits over residuum derived from calcareous siltstone, mudstone and sandstone. Knep soils are on escarpments, hills, mountain slopes and landslides. Slopes range from 1 to 60 percent. The average annual precipitation is about 450 mm, and the average annual air temperature is about 3.0 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Ustic Calcicryepts
TYPICAL PEDON: Knep channery loam at 1,914 meters in rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 18 cm; light brownish gray (2.5Y 6/2) channery loam, dark grayish brown (2.5Y 4/2) moist; moderate very fine and fine granular structure; soft, friable, nonsticky and nonplastic; common very fine and medium roots; very fine interstitial and tubular pores; 30 percent channers; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 18 cm thick)
Bw--18 to 43 cm; light brownish gray (2.5Y 6/2) channery loam, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium subangular blocky structure parting to moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; very fine interstitial and tubular pores; 10 percent channers; strongly effervescent; slightly alkaline (pH 7.6); clear smooth boundary. (0 to 25 cm thick)
Bk--43 to 61 cm; light brownish gray (2.5Y 6/2) channery loam, dark grayish brown (2.5Y 4/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; very fine interstitial and tubular pores; 15 percent fine irregular carbonate masses in matrix; 20 percent channers; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (15 to 70 cm thick)
Cr--61 cm; moderately cemented sedimentary beds.
TYPE LOCATION: Sweet Grass County, Montana; USGS Raspberry Butte, Montana topographic quadrangle; 45 degrees 55 minutes 13.70 seconds north latitude and 110 degrees 13 minutes 41.63 seconds west longitude.
RANGE IN CHARACTERISTICS:
Depth to paralithic contact -- 50 to 100 cm
Average annual soil temperature -- 2.5 to 4.5 degrees C.
Average summer soil temperature -- 12.0 to 14.0 degrees C.
Control Section
Clay content averages 18 to 34 percent
Rock fragments average 5 to 25 percent
A horizon
Hue: 2.5Y or 10YR dry or moist
Value: 4 to 6 dry; 3 or 4 moist
Chroma: 2 or 3 dry or moist
Texture (less than 2mm): loam or silt loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 30 percent gravel or channers; 0 to 5 percent cobbles
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 6.6 to 8.4
Bw horizon (where present)
Hue: 2.5Y or 10YR dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3 dry or moist
Texture (less than 2mm): loam or silt loam
Clay content: 18 to 30 percent
Rock fragments: 0 to 30 percent gravel or channers
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 7.4 to 8.4
Bk horizons
Hue: 2.5Y or 10YR dry or moist
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3 dry or moist
Texture (less than 2mm): loam, silt loam or silty clay loam
Clay content: 18 to 34 percent
Rock fragments: 0 to 30 percent gravel or channers
Parafragments: 0 to 30 percent paragravel or parachanners
Calcium carbonate equivalent: 15 to 30 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Kenosha (CO) - have an ustic moisture regime that borders on aridic
Lyonsbridge (MT) - are very deep
GEOGRAPHIC SETTING:
Landform: escarpments, hills, mountain slopes and landslides
Elevation: 1,825 to 2,325 meters
Slope: 1 to 60 percent
Parent material: slope alluvium, colluvium or slide deposits over residuum derived from calcareous siltstone, mudstone and sandstone
Mean annual precipitation: 400 to 600 cm
Mean annual air temperature: 1.5 to 3.5 degrees C.
Frost-free period: 30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; 1.5 to 15.0 um/sec.
USE AND VEGETATION: The soil is used principally for rangeland. Vegetation is mainly bluebunch wheatgrass and mountain big sage.
DISTRIBUTION AND EXTENT: These soils are of small extent in southwestern and central Montana. MLRAs 43B and 46.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Sweet Grass County, Montana, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- 0 to 18 cm (A horizon);
Cambic horizon - 18 to 43 cm (Bw horizon);
Calcic horizon -- 43 to 61 cm (Bk horizon);
Paralithic contact -- at 61 cm (Cr horizon); and
Particle-size control section -- 25 to 61 cm (part of Bw, Bk horizons).
Knep soils have a cryic temperature regime, an ustic moisture regime, and a typic soil moisture subclass.
Additional Information: Because of the ustic moisture regime, the type location was moved from Clark County, Idaho to Sweet Grass County, Montana (5/16/2017).
National Cooperative Soil Survey
U.S.A.