LOCATION HINGHAM MTEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Aridic Haplustolls
TYPICAL PEDON: Hingham loam, in cropland (colors are for dry soil unless otherwise noted).
Ap--0 to 7 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak very fine subangular structure; soft, very friable, sticky and slightly plastic; many very fine roots; common very fine pores; neutral (pH 7.0); abrupt smooth boundary. (5 to 10 inches thick)
Bw--7 to 14 inches; light olive brown (2.5Y 5/4) loam, olive brown (2.5Y 4/4) moist; moderate fine and medium subangular blocky structure; soft, very friable, sticky and slightly plastic; many very fine roots; many very fine pores; neutral (pH 7.0); clear smooth boundary. (5 to 9 inches thick)
Bk1--14 to 22 inches; light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; few fine seams of lime; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (7 to 22 inches thick)
Bk2--22 to 35 inches; light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine pores; few fine seams of lime; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (11 to 24 inches thick)
Bk3--35 to 60 inches; light brownish gray (2.5Y 6/2) very fine sandy loam, grayish brown (2.5Y 5/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few very fine pores; few fine seams of lime; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Hill County, Montana; 500 feet north and 1,000 feet west of the SE corner of sec. 21, T. 32 N., R. 11 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Soil moisture control section - between 4 and 12 inches; dry in some part six-tenths or more of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees F or higher.
Mollic epipedon thickness - 7 to 10 inches.
Particle-size control section - 5 to 18 percent clay.
Depth to Bk horizon - 10 to 16 inches.
Ap horizon - Hue: 10YR or 2.5Y
Value: 2 or 3 moist
Chroma: 2 or 3
Clay content: 5 to 18 percent
Reaction: pH 6.1 to 7.8
Pedons that have an Ap horizon less than 7 inches thick have mollic epipedon when mixed to 7 inches.
Bw horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3 or 4 moist
Chroma: 2, 3, or 4
Texture: silt loam, loam, or very fine sandy loam
Clay content: 5 to 18 percent
Reaction: pH 6.1 to 7.8
Bk horizons - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: silt loam or very fine sandy loam
Clay content: 5 to 18 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - till plains and lake plains.
Elevation - 2,600 to 3,200 feet.
Slope- 0 to 8 percent.
Parent material - alluvium, glaciolacustrine, or eolian deposits.
Climate - long, cold winters; moist springs; hot, dry summers.
Mean annual precipitation - 10 to 14 inches, most of which falls during spring and early summer.
Mean annual air temperature - 42 to 45 degrees F.
Frost-free period - 105 to 120 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Hingham soils are used as nonirrigated cropland and rangeland. The potential plant community is bluebunch wheatgrass, green needlegrass, needleandthread, and western wheatgrass.
DISTRIBUTION AND EXTENT: Hingham soils are of small extent in north-central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hill County, Montana, 1994; proposed in Hill County, Montana, 1991. Hingham is the name of a town in Hill County, Montana.
REMARKS: Soil interpretation record: MT1271. The diagnostic horizons recognized in this pedon are: a mollic epipedon (mixed) from the surface to 7 inches (Ap horizon) and a cambic horizon from 7 to 14 inches (Bw horizon); and a horizon of secondary carbonate accumulation (Bk1, Bk2 horizons). Hingham soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.
ADDITIONAL INFORMATION: Laboratory data S89MT-041-003, sample number 89T7333-7334; S88MT-041-000, sample number 88P5187S-88P5189S.