LOCATION FARNUF MT+ND SD WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Farnuf loam, in grassland. (Colors are for dry soil unless otherwise noted)
A--0 to 18 centimeters (about 0 to 7 inches); dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate very thin platy structure in the upper part and moderate medium prismatic structure in the lower part with plates and prisms that separate to moderate very fine granules; hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; many very fine and fine pores; slightly alkaline (pH 7.4); clear smooth boundary. (10 to 23 centimeters, about 4 to 9 inches, thick)
Bt--18 to 38 centimeters (about 7 to 15 inches); brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; strong medium prismatic structure parting to strong fine and medium subangular blocky; very hard, friable, sticky and plastic; many fine and very fine roots; many fine and very fine pores and few medium pores; continuous faint dark grayish brown (10YR 4/2) clay films on faces of peds; slightly alkaline (pH 7.6); clear wavy boundary. (13 to 56 centimeters, about 5 to 22 inches, thick)
Bk1--38 to 61 centimeters (about 15 to 24 inches); pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; moderate medium prismatic structure that separates to weak medium and fine blocky; hard, friable, sticky and plastic; many fine and very fine roots; many fine and very fine pores and few medium pores; few masses of lime; strongly effervescent; moderately alkaline (pH 8.3); diffuse wavy boundary.
Bk2--61 to 91 centimeters (about 24 to 36 inches); light gray (10YR 7/2) loam, grayish brown (10YR 5/2) moist; weak coarse blocky structure; hard, friable, sticky and slightly plastic; common fine and very fine roots; common fine and very fine pores; 5 percent gravel; common masses of lime; continuous faint coatings of lime on gravel; strongly effervescent; moderately alkaline (pH 8.4); diffuse wavy boundary. (Combined Bk horizons 25 to 97 centimeters, about 10 to 38 inches, thick)
BC--91 to 152 centimeters (about 36 to 60 inches); very pale brown (10YR 7/3) loam consisting of layers of stratified sandy clay loam and fine sandy loam, brown (10YR 5/3) moist; massive; hard, very friable, sticky and slightly plastic; few fine and very fine roots; common fine and very fine pores; disseminated lime; strongly effervescent; strongly alkaline (pH 8.5).
TYPE LOCATION: Cascade County, Montana; 1,600 feet west and 1,240 feet south of the northeast corner of sec. 36, T. 18 N., R. 6 E at 1,097 meters (about 3,600 feet) elevation.
RANGE IN CHARACTERISTICS:
Soil temperature - 3.3 to 8.3 degrees C (about 38 to 47 degrees F).
Moisture control section - between 10 and 30 centimeters (about 4 and 12 inches).
Mollic epipedon thickness - 18 to 38 centimeters (about 7 to 15 inches) and includes all or only part of the argillic horizon.
Depth to secondary lime horizon - 25 to 64 centimeters (about 10 to 25 inches).
A horizon
Hue: 10YR or 2.5Y
Value: 3, 4, or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture (less than 2 mm): loam, clay loam, sandy clay loam, sandy loam, or silt loam
Clay content: 15 to 32 percent
Rock fragments: 0 to 35 percent
0 to 20 percent stones and cobbles
0 to 15 percent gravel
Reaction: pH 6.1 to 7.8
Bt horizon(s)
Hue: 7.5YR, 10YR, or 2.5Y
Value: 3, 4, 5, or 6 dry; 2, 3, or 4 moist
Chroma: 2, 3, or 4
Texture (less than 2 mm): loam, silt loam, clay loam, sandy clay loam or silty clay loam
Clay content: 20 to 35 percent
Sand content: less than 35 percent fine sand and coarser sand
Rock fragments: 0 to 35 percent gravel
Reaction: pH 6.1 to 7.8
Some pedons have a thin Btk horizon.
Bk horizon(s)
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture (less than 2 mm): very fine sandy loam, fine sandy loam, sandy loam, sandy clay loam, loam, silt loam, silty clay loam, or clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 35 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
BC, C and BCk horizons, where present
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture (less than 2 mm): loam or clay loam--the strata consist of thin layers of fine sandy loam, sandy clay loam, clay loam, silty clay loam, silty clay, and silt loam
Clay content: 12 to 35 percent
Rock fragments: 0 to 35 percent
0 to 10 percent cobbles
0 to 25 percent gravel
Calcium carbonate equivalent: 3 to 12 percent
EC: 0 to 8 mmhos/cm
Reaction: pH 7.4 to 9.0
COMPETING SERIES:
Absarook (MT) - has a lithic contact of sandstone at depths of 50 to 100 centimeters (about 20 to 40 inches).
Archmesa (CO) - has a paralithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Beartooth (MT) - has more than 35 percent rock fragments in the Bk horizons.
Beeno (WY) - has a paralithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Bielenberg (MT) - are noncalcareous throughout the profile.
Bookcliff (UT) - are calcareous at a depth of 4 inches, are not stratified in the C horizon, and have hard sandstone bedrock at a depth of 100 to 150 centimeters (about 40 to 60 inches).
Burtoner (MT) - has a paralithic contact at a depth of 50 to 97 centimeters (about 20 to 38 inches).
Clancy (MT) - has a lithic contact of granite at depths of 50 to 100 centimeters (about 40 to 60 inches).
Clasoil (MT) - does not have a horizon of secondary calcium carbonate accumulation; and is loamy skeletal below the argillic horizon.
Dooley (MT) - has till above a depth of 100 centimeters (about 40 inches) that has a bulk density greater than 1.6.
Doughty (MT) - has a calcic horizon.
Empedrado (CO) - has argillic horizons as deep as 50 to 100 centimeters (about 20 to 40 inches), and the depth to lime is usually deeper than 60 centimeters (about 24 inches).
Fairfield (MT) - has calcic horizons.
Farside (MT) does not have a horizon of secondary carbonate accumulation.
Felor (SD) - has 2B horizons of silty clay below a depth of 70 centimeters (about 28 inches), and the depth to carbonates is typically deeper than 75 centimeters (about 30 inches).
Greenway (SD) - has a high bulk density till substratum that has 35 to 45 percent clay.
Gurney (SD) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Hangdo (UT) - does not have a Bk horizon or free carbonates above a depth of 100 centimeters (about 40 inches).
High (CO) - has a calcic horizon.
Hoppers (MT) - has a lithic contact at depths of 50 to 100 centimeters (about 20 to 40 inches).
Hyalite (MT) - have a sandy-skeletal discontinuity above a depth of 100 centimeters (about 40 inches).
Jeffcity (MT) - has a lithic contact of granite at depths of 50 to 100 centimeters (about 20 to 40 inches).
Kokoruda (MT) - do not have a horizon of carbonate accumulation.
Livona (ND) - has a discontinuity of till at depths of 25 to 50 centimeters (about 10 to 20 inches).
Martinsdale (MT) - has calcic horizons.
Maudlin (CO) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Meagher (MT) - has a loamy-skeletal discontinuity; and has a calcic horizon.
Moen (CO) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Moento (CO) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Perrypark (CO) - Does not have horizons of secondary carbonate accumulation.
Pianohill (MT) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Placerton (MT) - has a lithic contact of granite at depths of 100 to 150 centimeters (about 40 to 60 inches).
Reeder (ND) - has a paralithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Reedwest (MT) - has a paralithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Sipple (MT) has a lithologic discontinuity
Snakejohn (UT) - has a lithic contact within a depth of 150 centimeters (about 60 inches).
Sponseller (AZ) - is noncalcareous throughout the profile.
Trag (CO) does not have a horizon of secondary carbonate accumulation.
Tragmon (CO) - does not have horizons of secondary carbonate accumulation.
Trazuni (NM) - does not have horizons of secondary carbonate accumulation.
Trujillo (CO) - does not have a horizon of secondary carbonate accumulation within 100 centimeters (about 40 inches) of the surface.
Ulrant (WY) - has calcic horizons.
Vida (MT) - has till above a depth of 100 centimeters (about 40 inches) that has a bulk density greater than 1.6; and is less then 25 centimeters (about 10 inches) deep to carbonates.
Watne (MT) - has a calcic horizon.
Watrous (ND) - has a lithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Wemple (MT) - has a paralithic contact at a depth of 50 to 100 centimeters (about 20 to 40 inches).
Williams (ND) - has till above a depth of 100 centimeters (about 40 inches) that has a bulk density greater than 1.6.
Yegen (MT) - has 35 to 50 percent fine sand and coarser sand in the argillic horizon.
GEOGRAPHIC SETTING:
Landform- stream terraces; alluvial fans; hills; sedimentary plains; glacial lake plains; moraines and outwash plains.
Elevation 579 to 1,890 meters (about 1,900 to 6,200 feet).
Slope - 0 to 35 percent.
Parent material - alluvium derived from mixed rock sources, glaciolacustrine or glaciofluvial deposits.
Climate - long, cold winters; moist springs and warm summers.
Mean annual precipitation 305 to 610 millimeters (about 12 to 24 inches), with areas receiving less than 356 millimeters (about 14 inches) of precipitation having cooler temperatures and less evaporation. Most of the precipitation falls during spring and early in summer.
Mean annual air temperature 1.1 to 7.2 degrees C. (about 34 to 45 degrees F).
Frost-free period - 70 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arnegard, Reeder and Shambo soils.
Arnegard soils have a mollic epipedon that is 40 to 75 centimeters, about 16 to 30 inches thick, do not have an argillic horizon, and are in swales.
Reeder soils have a paralithic contact at 50 to 100 centimeters, about 20 to 40 inches, and are on shoulders and summits.
Shambo soils do not have an argillic horizon and are on similar landform positions.
DRAINAGE AND PERMEABILITY: Well drained. High saturated hydraulic conductivity.
USE AND VEGETATION: Farnuf soils are used mainly for irrigated and nonirrigated cropland. The potential native vegetation is primarily mid and short grasses such as western wheatgrass, prairie sandreed, green needlegrass, little bluestem, needleandthread, blue grama, shrubs, and forbs.
DISTRIBUTION AND EXTENT: Farnuf soils are widely distributed in the eastern plains of Montana and in western North Dakota. They are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Cascade County, Montana, 1969.
REMARKS: Soil interpretation records: MT0009, MT0231, MT0241, MT0813, MT0814.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soils to a depth of 38 centimeters, about 15 inches (A and Bt horizons); argillic horizon - the zone from 18 to 38 centimeters, about 7 to 15 inches (Bt horizon); horizon of lime accumulation - the zone from 38 to 91 centimeters, about 15 to 36 inches (Bk1 and Bk2 horizons); particle-size control section - the zone from 18 to 38 centimeters, about 7 to 15 inches (Bt horizon).