LOCATION ANAMAC MT
Established Series
Rev. PEM-KTS-RJS
03/2011
ANAMAC SERIES
The Anamac series consists of very deep, well drained soils that formed in alluvium derived from sandstone, argillite or fine grained igneous rocks. These soils are on alluvial fans, stream terraces or hills. Slopes are 0 to 15 percent. Mean annual precipitation is about 12 inches and mean annual air temperature is about 41 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aridic Haplustolls
TYPICAL PEDON: Anamac loam, in cropland (colors are for dry soil unless otherwise noted).
Ap--0 to 4 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak coarse platy structure parting to strong fine and medium granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, few fine and few coarse roots; many very fine and fine, and few medium pores; slightly alkaline (pH 7.4); abrupt smooth boundary. (4 to 9 inches thick)
Bw--4 to 12 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak medium and coarse subangular blocky structure parting to strong fine and medium granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine, few fine and few coarse roots; many very fine, common fine and fine medium tubular and interstitial pores; slightly alkaline (pH 7.4); clear smooth boundary. (7 to 15 inches thick)
Bk1--12 to 18 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium and coarse prismatic structure parting to strong medium and coarse subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine, few fine and few coarse roots; many very fine, common fine and few medium tubular and interstitial pores; 5 percent gravel; disseminated lime, few fine masses of calcium carbonate, distinct calcium carbonate coatings on undersides of fragments; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary.
Bk2--18 to 31 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; weak coarse prismatic structure parting to weak medium and fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few common roots; many very fine and common fine tubular and interstitial pores; 5 percent gravel; disseminated calcium carbonate, few fine masses of calcium carbonate, distinct lime coatings on undersides of fragments; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (Combined thickness of Bk horizons is 19 to 43 inches.)
BC--31 to 60 inches; very pale brown (10YR 7/4) loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine and few coarse roots; many very fine tubular and interstitial pores; 5 percent gravel; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Jefferson County, Montana; 50 feet north and 2,190 feet east of the SW corner of sec. 34, T. 2 N., R. 4 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 46 degrees F.
Mollic epipedon thickness - 7 to 15 inches
Depth to the secondary carbonate accumulation - 11 to 24 inches
Note: Where irrigated, some pedons may have a thin O horizon.
A horizon
Hue: 10YR or 2.5Y; dry or moist
Chroma: 2 or 3; dry or moist
Texture: loam, silt loam or clay loam
Clay content: 18 to 30 percent
Rock fragments: 0 to 25 percent--0 to 15 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.4 to 8.4
Saline phase
EC: 8 to 16 mmhos/cm
SAR: 13 to 30
Reaction: pH 7.4 to 9.0
Bw horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 0 to 10 percent
Reaction: pH 7.4 to 8.4
Saline phase
EC: 16 to 40 mmhos/cm
SAR: 13 to 40
Reaction: pH 8.5 to 9.6
Bk horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: silt loam, loam or clay loam
Clay content: 8 to 30 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0
Saline phase
EC: 8 to 25 mmhos/cm
SAR: 13 to 40
Reaction: pH 8.5 to 9.6
BC horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: sandy loam, loam, clay loam or silty clay loam
Clay content: 10 to 35 percent
Rock fragments: 0 to 25 percent gravel
Calcium carbonate equivalent: 3 to 10 percent
Reaction: pH 7.9 to 9.0
Saline phase
EC: 2 to 16 mmhos/cm
SAR: 4 to 20
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
Boxwell (MT) - is moderately deep to a paralithic contact
Conn (MT) - have a calcic horizon
Fortbenton (MT) - have a lithologic discontinuity
Kremlin (MT) - have cambic horizons
Littlemo (ND) - have a lithologic discontinuity
Waterhill (UT) - have hues of 5YR or 7.5YR throughout
GEOGRAPHIC SETTING:
Landform - alluvial fans, stream terraces or hills
Elevation - 4,000 to 6,500 feet
Slope - 0 to 15 percent
Parent material - alluvium derived from sandstone, argillite or fine grained igneous rocks
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 10 to 14 inches
Mean annual air temperature - 38 to 44 degrees F.
Frost-free period - 80 to 115 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Anamac soils are mainly used for rangeland, nonirrigated cropland, irrigated cropland, and hayland. The potential native vegetation is mainly bluebunch wheatgrass, needleandthread, western wheatgrass, blue gramma, prairie junegrass, vetch, fringed sagewort, big sagebrush, rubber rabbitbrush, and broom snakeweed.
DISTRIBUTION AND EXTENT: Anamac soils are of small extent in southwestern Montana. MLRA 44B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Jefferson County, Montana, 1998.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 12 inches (Ap, Bw horizons)
Zone of secondary calcium carbonate accumulation - from 12 to 31 inches (Bk1, Bk2 horizons)
Particle-size control section - from 10 to 40 inches (Bw, Bk1, Bk2, BC horizons)
Anamac soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
Additional Data:
Soil interpretation record: MT1554 and MT1555
National Cooperative Soil Survey
U.S.A.