LOCATION ALZADA MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Torrertic Haplustepts
TYPICAL PEDON: Alzada clay loam, in grassland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; light brownish gray (10YR 6/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; slightly acid (pH 6.4); clear smooth boundary. (2 to 4 inches thick)
Bw--2 to 10 inches; brown (10YR 5/3) clay, dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to moderate fine and medium subangular blocky; hard, firm, very sticky and very plastic; common very fine roots; few very fine and fine pores; common faint clay films on faces of peds and in pores; disseminated lime; sightly effervescent; mildly alkaline (pH 7.8); gradual smooth boundary. (6 to 15 inches thick)
Bk--10 to 16 inches; grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure; hard, friable, sticky and very plastic; common very fine roots; few fine masses of lime; strongly effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (4 to 7 inches thick)
2Bkyz--16 to 36 inches; gray (10YR 5/1) silty clay loam, very dark gray (10YR 3/1) moist; weak medium prismatic structure; hard, firm, sticky and plastic; many fine and medium masses and seams of gypsum crystals; few fine seams of other salts; few fine seams of lime; strongly effervescent; neutral (pH 7.2); gradual wavy boundary. (12 to 24 inches thick)
2C--36 to 60 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; massive; hard, firm, sticky and plastic; neutral (pH 7.2)
TYPE LOCATION: Carter County, Montana; 2,500 feet west and 2,200 feet north of the SE corner of sec. 24, T.9S., R.58E.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 47 degrees F.
Moisture control section - between 4 and 12 inches, dry in all parts between four-tenths and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees F. or higher.
Depth to Bk horizon - 8 to 16 inches.
Depth to Bkyz horizon - 12 to 22 inches.
A horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: sandy loam, loam, or sandy clay loam
Clay content: 15 to 50 percent
EC: 0 to 2 mmhos/cm
Reaction: pH 5.6 to 7.3
Bw horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4
Texture: silty clay loam or clay
Clay content: 35 to 50 percent
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.4 to 8.4
Bk horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3 or 4
Texture: silty clay loam or clay
Clay content: 35 to 50 percent
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.4 to 8.4
2Bkyz horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3, or 4 moist
Chroma: 1 or 2
Texture: silty clay loam or clay
Clay content: 35 to 50 percent
EC: 4 to 8 mmhos/cm
Gypsum: 1 to 5 percent
Reaction: pH 6.6 to 8.4
The 1 chroma are lithochromic.
2C horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 1 or 2
Texture: clay loam, silty clay loam, or clay
Clay content: 35 to 50 percent
EC: 4 to 8 mmhos/cm
Reaction: pH 6.6 to 8.4
The 1 chroma are lithochromic.
COMPETING SERIES:
Kobarter (MT) - does not have a lithologic discontinuity; has electrical conductivity of 4 to 16 mmhos/cm in Bz horizons.
Zayton (MT) - does not have a lithologic discontinuity; has horizon of sodium accumulation with an SAR of 16 to 30 and EC of 16-32 mmhos/cm.
GEOGRAPHIC SETTING:
Landform- alluvial fans and stream terraces
Elevation- 3,000 to 4,500 feet
Slope- 0 to 8 percent
Parent material - alluvium from mixed sources
Climate- long, cold winter; moist springs; warm summers
Mean annual precipitation - 10 to 14 inches
Mean annual air temperature - 41 to 45 degrees F.
Frost-free period - 110 to 130 days
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Alzada soils are used mainly for pasture and rangeland. The potential native vegetation is mainly western wheatgrass, prairie june-grass, blue grama, big sagebrush, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Southeastern Montana. Alzada soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Carter County, Montana, 1992. The name is for a town in Carter County, MT.
REMARKS: Soil interpretations records: MT0546 and MT0216. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 7 inches (A and Bw horizons); a cambic horizon from 2 to 16 inches (Bw, Bk horizons; a lithologic discontinuity at 16 inches (2Bkyz horizon). Alzada soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.
Classification changed from Borollic Camborthids to Aridic Ustochrepts in 1994.