LOCATION RIDGE MTEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid, shallow Typic Haplustepts
TYPICAL PEDON: Ridge sandy loam, forested (colors are for dry soil unless otherwise noted).
Oi--1/2 inch to 0; slightly decomposed forest litter. (1/2 to 2 inches thick)
A--0 to 2 inches; brown (10YR 5/3) sandy loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; loose, very friable, nonsticky and nonplastic; many fine roots; many fine and very fine pores; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (2 to 4 inches thick)
Bw1--2 to 6 inches; pale brown (10YR 6/3) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; many fine roots; many very fine and few fine pores; disseminated lime; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary.
Bw2--6 to 12 inches; pale brown (10YR 6/3) sandy loam, grayish brown (2.5Y 5/2) moist; moderate medium subangular blocky structure; soft, friable, nonsticky and nonplastic; many fine roots; common very fine and few fine pores; disseminated lime; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (Combined thickness of B horizons is 8 to 12 inches.)
Bk--12 to 16 inches; light gray (2.5Y 7/2) sandy loam, grayish brown (2.5Y 5/2) moist; massive; soft, friable, nonsticky and nonplastic; common fine roots; few very fine masses and fine threads of lime; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (2 to 4 inches thick)
Cr--16 to 60 inches; light gray (2.5Y 7/2) weakly consolidated sandy sedimentary beds that texture to loamy sand, grayish brown (2.5Y 5/2) moist; common fine roots in cracks; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Carter County, Montana; 2,500 feet north and 1,500 feet west of the SE corner of sec. 18, T. 8 S., R. 55 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - 8 to 20 inches and is moist in some part more than half the time during the growing season.
Control section - 5 to 20 percent clay.
Depth to Bk horizon - 10 to 16 inches.
Depth to Cr horizon - 12 to 20 inches.
Some pedons have a C horizon above the Cr horizon.
A horizon - Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3, or 4
Texture: sandy loam or loam
Clay content: 5 to 20 percent
Reaction: pH 7.4 to 7.8
The surface horizon, when mixed to a depth of 7 inches, does not meet the requirements for a mollic epipedon.
Bw horizons - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: sandy loam or loam
Clay content: 5 to 20 percent
Reaction: pH 7.4 to 8.4
Bk horizon - Hue: 10YR to 5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: sandy loam or loam
Clay content: 5 to 20 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Cr horizon - semiconsolidated interbedded sandy and loamy sedimentary beds that texture to sandy loam or loamy sand.
Reaction: pH 7.4 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - sedimentary plains and hills.
Elevation - 3,000 to 4,600 feet.
Slope- 4 to 65 percent.
Parent material - residuum derived from semiconsolidated interbedded sandy and loamy sedimentary beds.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 12 to 19 inches.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 105 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Ridge soils are used as grazeable woodland. Potential native vegetation is ponderosa pine with an understory of green needlegrass and western wheatgrass.
DISTRIBUTION AND EXTENT: Ridge soils are of limited extent on sedimentary uplands of eastern Montana. Ridge is a place name.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Carter County, Montana, 1992. Proposed: Carter County, Montana, 1980.
REMARKS: Soil interpretations record: MT0591.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon when mixed to a depth of 7 inches (A and Bw1 horizons); cambic horizon - from 4 to 12 inches (Bw1 and Bw2 horizons); paralithic contact - at 16 inches. Ridge soils have a frigid temperature regime and an ustic moisture regime.