LOCATION FAIRBERG MT
Tentative Series
Rev. LCB-JAL-EMM
07/2012
FAIRBERG SERIES
The Fairberg series consists of very deep, somewhat poorly drained soils that formed in alluvium. These soils are on flood plains. Slopes are 0 to 3 percent. Mean annual precipitation is about 15 inches and mean annual temperature is about 41 degrees F.
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Oxyaquic Calciustolls
TYPICAL PEDON: Fairberg silt loam, in irrigated hayland (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; slightly decomposed organic material; clear smooth boundary. (0 to 2 inches thick)
A--2 to 11 inches; gray (10YR 6/1) silt loam, very dark grayish brown (10YR 3/2) moist; moderate very fine platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular and interstitial pores; disseminated lime; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 10 inches thick)
Bk--11 to 17 inches; gray (10YR 6/1) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to weak medium and fine subangular blocky; slightly hard, very friable, moderately sticky and slightly plastic; common very fine roots; many very fine tubular and interstitial pores; disseminated lime; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 22 inches thick)
Bkg1--17 to 37 inches; light gray (10YR 7/1) silt loam, gray (10YR 5/1) moist; weak medium subangular blocky structure parting to moderate very fine granular; soft, very friable, moderately sticky and slightly plastic; common very fine roots; many very fine tubular and interstitial pores; disseminated lime; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary.
Bkg2--37 to 52 inches; light gray (10YR 7/1) silt loam, gray (10YR 5/1) moist; weak medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; few very fine roots; many very fine tubular and interstitial pores; common medium faint gray (10YR 5/1) redox reductions, moist; disseminated lime; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (combined thickness of the Bkg horizons is 15 to 35 inches thick)
2Bkg3--52 to 60 inches; gray (5Y 6/1) gravelly loam, dark gray (5Y 4/1) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; very dark gray (5Y 3/1) moist seams of organic enriched material; common medium prominent brown (7.5YR 4/2) redox depletions, moist; 20 percent gravel; disseminated lime; common medium and fine seams and masses of lime; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Meagher County, Montana; 2,100 feet north and 900 feet west of the SE corner of sec. 27, T. 9 N., R. 6 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 45 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon - 10 to 16 inch dry color requirement is waived because calcium carbonate equivalent is greater than 15 percent.
Depth to seasonal water table - 30 to 42 inches.
Depth to color mottling - 25 to 36 inches.
A horizons
Chroma: 1 or 2
Clay content: 20 to 27 percent
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 7.9 to 8.4
Bw horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3, 4, or 5 moist
Chroma: 1 or 2
Clay content: 20 to 27 percent
Calcium carbonate equivalent: 20 to 35 percent
Reaction: pH 7.9 to 8.4
Bkg1 horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 1 or 2
Texture: silt loam or silty clay loam
Clay content: 20 to 30 percent
Calcium carbonate equivalent: 20 to 35 percent
Reaction: pH 7.9 to 8.4
Bkg2 horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 1 or 2
Redoximorphic features: Hue: 10YR or 7.5YR; Value: 4 or 5 moist; Chroma: 1 or 2
Textures: silt loam or silty clay loam
Clay content: 20 to 30 percent
Calcium carbonate equivalent: 20 to 35 percent
Reaction: pH 7.9 to 8.4
2Bkg3 horizon
Hue: 2.5Y or 5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 1 or 2
Redoximorphic features--Value: 5 or 6 dry, 4 or 5 moist; Chroma: 2, 3, or 4
Texture: loam, silt loam, sandy loam, or sand
Clay content: 10 to 20 percent
Rock fragments: 0 to 25 percent - 0 to 25 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 10 to 30 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - flood plains.
Elevation - 4,500 to 6,000 feet.
Slope - 0 to 3 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; short, warm summers.
Mean annual precipitation - 15 to 19 inches.
Mean annual air temperature - 38 to 43 degrees F.
Frost-free period - 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; moderate permeability.
USE AND VEGETATION: Fairberg soils are used mainly for grass hay and grazing for livestock. The potential native vegetation is mainly basin wildrye, slender wheatgrass, bearded wheatgrass, Canby bluegrass, western wheatgrass, sedges, shrubby cinquefoil, other perennial grasses, and forbes.
DISTRIBUTION AND EXTENT: Fairberg soils are of small extent in the valleys of western Montana. MLRAs 43B, 44B, and 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Meagher County, Montana, 1992. Fairberg is a coined name.
REMARKS: Soil interpretation record: MT1468.
Diagnostic horizons and features recognized in this pedon are:
Organic layer - 2 inches thick (Oi horizon);
Mollic epipedon - from 2 to 17 inches (A and Bk horizons);
Calcic horizon - from 17 to 52 inches (Bkg1, Bkg2 horizons);
Discontinuity - from 52 to 60 inches (2Bkg3 horizon).
The Fairberg soils have a frigid temperature regime and an ustic moisture regime that borders on aquic.
National Cooperative Soil Survey
U.S.A.