LOCATION KERRDAM MTEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, active, frigid Calcic Haploxerepts
TYPICAL PEDON: Kerrdam silt loam, in croplands (colors are for dry soil unless otherwise noted).
Ap--0 to 5 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine tubular pores; neutral (pH 7.0); abrupt smooth boundary. (3 to 10 inches thick)
Bw--5 to 12 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak very coarse prismatic structure parting to weak coarse subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many fine and medium roots; few very fine tubular pores; neutral (pH 7.2); clear smooth boundary. (4 to 17 inches thick)
Bk--12 to 16 inches; light gray (10YR 7/2) silt loam, pale brown (10YR 6/3) moist; weak very coarse prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many fine and medium tubular pores; disseminated lime and common medium masses of lime; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (4 to 15 inches thick)
C1--16 to 34 inches; light gray (10YR 7/2) very fine sandy loam, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine roots; slightly effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (10 to 30 inches thick)
C2--34 to 60 inches; light gray (10YR 7/2) silt loam, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; slightly effervescent; moderately alkaline (pH 8.4)
TYPE LOCATION: Lake County, Montana; 250 feet west and 30 feet north of the SE corner of sec. 34, T. 22 N., R. 23 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Bk horizon: 12 to 20 inches.
Some pedons have 10 percent weakly cemented durinodes.
Ap horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Texture: silt loam or very fine sandy loam
Clay content: 5 to 18 percent
Reaction: pH 6.6 to 7.3
The surface layer, where mixed to a depth of 7 inches, will not meet the color requirements for a mollic epipedon.
Bw horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 3 or 4
Texture: silt loam or very fine sandy loam
Clay content: 5 to 18 percent
Reaction: pH 6.6 to 7.8
Bk horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 5, 6, or 7 moist
Chroma: 2, 3, or 4
Texture: very fine sandy loam or silt loam
Clay content: 5 to 18 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
C1 horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 6 or 7 moist
Chroma: 2, 3, or 4
Texture: silt loam or very fine sandy loam
Clay content: 0 to 5 percent
Reaction: pH 7.4 to 8.4
C2 horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 6 or 7 moist
Chroma: 2, 3, or 4
Texture: silt loam, very fine sandy loam, or loamy very fine sand
Clay content: 0 to 5 percent
SAR: 13 to 20
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Dryfork (MT) - have SAR of 13 to 40 in the Bw and Bk horizons.
Watercanyon (ID) - are mainly calcareous in the A and Bw horizons; do not have an SAR of 13 or greater above a depth of 40 inches.
GEOGRAPHIC SETTING:
Landform - stream terraces, lake plains and terraces and dissected alluvial fans.
Elevation - 2,500 to 3,000 feet.
Slope - 0 to 30 percent.
Parent material - mixed silty, lacustrine, and eolian deposits.
Climate - long, cold winters; moist falls and springs; warm, dry summers.
Mean annual precipitation - 10 to 14 inches, most of which falls as snow or rain in late fall, winter, and in spring.
Mean annual temperature - 41 to 45 degrees F.
Frost-free period - 105 to 120 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used as irrigated alfalfa-grass hayland, crested wheatgrass, improved pastureland, and rangeland. Potential native vegetation is mainly bluebunch wheatgrass, prairie junegrass, Sandberg bluegrass, and needleandthread.
DISTRIBUTION AND EXTENT: Kerrdam soils are of small extent in intermountain valleys of western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed in Lake County, Montana, 1982.
REMARKS: Soil interpretation records: MT0729 and MT1023. Diagnostic horizons and features recognized in this pedon are: a dark colored surface horizon from 0 to 5 inches, that when mixed to 7 inches is ochric (Ap horizon); a cambic horizon from 5 to 12 inches (Bw horizon); an accumulation of lime from 12 to 16 inches (Bk horizon). A particle-size control section from 10 to 40 inches (Bw, Bk, C1, C2 horizons). The Kerrdam soils have a frigid temperature regime and a xeric moisture regime that borders on aridic.
ADDITIONAL DATA: Laboratory Data: S69MT-047-008