LOCATION MOLTONER MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, frigid Aeric Fluvaquents
TYPICAL PEDON: Moltoner silt loam, in rangeland (Colors are for moist soil unless otherwise noted).
Az--0 to 5 inches; dark brown (10YR 3/3) silt loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial pores; disseminated lime; few very fine masses of salt; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 6 inches thick)
Cz1--5 to 20 inches; dark grayish brown (10YR 4/2) silt loam with thin strata of fine and medium sand, grayish brown (10YR 5/2) dry; few faint strong brown (7.5YR 5/6) redox concentrations; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine roots; many very fine interstitial and tubular pores; disseminated lime; few very fine masses of salt; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary.
Cz2--20 to 27 inches; dark grayish brown (2.5Y 4/2) silt loam, grayish brown (10YR 5/2) dry; common faint strong brown (7.5YR 5/6) redox concentrations; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine interstitial and tubular pores; disseminated lime; few very fine masses and threads of salt; slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (Combined thickness of Cz horizons is 10 to 30 inches).
Czg1--27 to 35 inches; grayish brown (2.5Y 5/2) coarse sandy loam consisting of thinly stratified layers of loam, silt loam and coarse sand, light brownish gray (10YR 6/2) dry; common faint very dark gray (5Y 3/1) redox depletions; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial and tubular pores; disseminated lime; few very fine masses and threads of salt; slightly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (0 to 15 inches thick)
Czg2--35 to 49 inches; grayish brown (2.5Y 5/2) loam consisting of thinly stratified layers of silt and fine sand, light brownish gray (10YR 6/2) dry; common distinct strong brown (7.5YR 5/6) redox concentrations; common faint dark gray (5Y 4/1) redox depletions; massive; hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; disseminated lime; few very fine threads of salt; slightly effervescent; moderately alkaline (pH 8.3); clear wavy boundary. (7 to 35 inches thick).
Cg--49 to 60 inches; grayish brown (2.5Y 5/2) loam consisting of thinly stratified layers of loam, clay and silt loam, light brownish gray (10YR 6/2) dry; many distinct strong brown (7.5YR 5/6) redox concentrations; many distinct dark gray (5Y 4/1) redox depletions; massive; hard, firm, slightly sticky and slightly plastic; few very fine tubular pores; disseminated lime; slightly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Jefferson County, Montana; 1,700 feet north and 1,900 feet west of the southeast corner of sec. 23, T. 2 N., R. 1 W.
RANGE IN CHARACTERISTICS:
Annual soil Temperature - 42 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to water table - 12 to 24 inches during early spring runoff and irrigation.
The surface layer, when mixed to 7 inches, does not meet the color requirements for a mollic epipedon. A thin surface mat of partially decomposed vegetation is allowed.
This soil has an irregular decrease in organic carbon.
Az horizon - Hue: 10YR or 2.5Y
Value: 4, 5 or 6 dry; 2, 3, 4 or 5 moist
Chroma: 1, 2 or 3
Texture: silt loam or silty clay loam
Clay content: 15 to 30 percent
Rock fragments: 0 to 15 percent pebbles
Electrical conductivity: 8 to 16 mmhos/cm
Sodium absorption ratio: 13 to 30
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.9 to 9.6
Cz and Czg horizons - Hue: 10YR, 2.5Y or 5Y
Value: 4, 5, 6 or 7 dry; 3, 4 or 5 moist
Redox Concentrations: none to common 7.5YR 5/6 or 5YR 5/6
Redox depletions: none to common 10YR 3/1, 10YR 4/1, and 5Y 4/1
Texture: loam, clay loam, coarse sandy loam or silt loam consisting of thinly stratified layers of silt, clay, loamy fine sand, fine sand or coarse sand, sand and gravel.
Clay content: 18 to 35 percent
Rock fragments: 0 to 20 percent pebbles
Electrical conductivity: 8 to 16 mmhos/cm
Sodium absorption ratio: 13 to 30
Calcium carbonate equivalent: 10 to 20 percent (disseminated lime)
Reaction: pH 7.9 to 9.6
Cg horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6 or 7 dry; 3, 4, 5 or 6 moist
Chroma: 1 or 2
Redox concentrations: few to common 7.5YR 5/6 or 5YR 5/6
Redox depletions: common to many 10YR 4/1, 10YR 3/1, 5Y 3/1 or 5Y 4/1
Texture: loam, clay loam or silt loam consisting of thinly stratified layers of loamy fine sand, fine sand or sand and gravel, silt and clay
Clay content (weighted average): 18 to 35 percent
Rock fragments: 0 to 20 percent pebbles
Electrical conductivity: 8 to 16 mmhos/cm
Sodium absorption ratio: 4 to 20
Calcium carbonate equivalent: 10 to 20 percent
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
Iceslew (WY) - do not have an SAR of 4 to 20 above a depth of 40 inches; are ponded March through June; have moderate permeability.
GEOGRAPHIC SETTING:
Landform - flood plains, flood plain steps and drainageways.
Elevation - 3,800 to 5,000 feet.
Slope- 0 to 2 percent.
Parent material - saline and sodic alluvium derived from mixed rock sources.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 40 to 44 degrees F.
Frost-free period - 90 to 115 days.
DRAINAGE AND PERMEABILITY: Poorly drained, moderately slow permeability.
USE AND VEGETATION: Moltoner soils are primarily used for rangeland, grass hay and pasture. The potential native vegetation is mainly Western wheatgrass, basin wildrye, alkali sacaton, Inland saltgrass, bluegrass and greasewood.
DISTRIBUTION AND EXTENT: Moltoner soils are of small extent along major rivers and their tributaries in southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jefferson County, Montana, 1998.
REMARKS: Soil interpretation record: MT1573. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the surface to 7 inches mixed (Az and Cz1 horizons); an accumulation of salt and sodium from the surface to 60 inches (All horizons); a particle size control section from 10 to 40 inches (Cz1, Cz2, Czg1 and Czg2 horizons). Moltoner soils have a frigid temperature regime and an aquic moisture regime.