LOCATION ORAID                   MT

Established Series
Rev. COC/RER/EMM
04/2014

ORAID SERIES

The Oraid series consists of moderately deep, somewhat excessively drained soils that formed in slope alluvium or colluvium over residuum from non-calcareous sedimentary rocks. These soils are on ridgetops, mountain slopes, scarp slopes, and foothills. Slopes are 2 to 60 percent. Mean annual precipitation is about 530 mm, and mean annual temperature is about 5.0 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Typic Ustorthents

TYPICAL PEDON: Oraid extremely flaggy sandy loam, forested. (Colors are for dry soil unless otherwise noted.)

0i--0 to 3 cm; forest litter of undecomposed and decomposed needles, twigs, and cones. (0 to 6 cm thick)

A1--3 to 9 cm; light brown (7.5YR 6/4) extremely flaggy sandy loam, brown (7.5YR 4/4) moist; moderate fine granular structure; soft, very friable, non-sticky and nonplastic; few coarse roots, common medium roots, and many fine and very fine roots; common medium and fine pores; 35 percent flagstones and 25 percent angular gravel; moderately acid (pH 5.9); diffuse wavy boundary. (5 to 10 cm thick)

A2--9 to 28 cm; light yellowish brown (10YR 6/4) extremely flaggy heavy loamy sand, dark yellowish brown (10YR 4/4) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; few coarse roots, common medium roots, and many fine and very fine roots, with root mattings between the fragments; many fine pores; 55 percent flagstones and 20 percent angular gravel; moderately acid (pH 5.9); diffuse wavy boundary. (0 to 46 cm thick)

AC--28 to 67 cm; very pale brown and pale brown (10YR 7/3 and 10YR 6/3) extremely flaggy loamy sand, yellowish brown and dark yellowish brown (10YR 5/4 and 10YR 4/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few coarse roots and common medium roots; many medium pores; 60 percent flagstones and 25 percent angular gravel; strongly acid (pH 5.4); gradual wavy boundary. (28 to 51 cm thick)

R--67 to 79 cm; fractured non-calcareous sandstone; few fine roots in cracks in the upper few inches.

TYPE LOCATION: Fergus County, Montana; 282 meters north and 168 meters west of the SE corner of sec. 9, T. 13 N., R. 17 E.

RANGE IN CHARACTERISTICS:

Soil temperature: 6.0 to 7.0 degrees C.
Depth to bedrock: 50 to 100 cm

A horizons:
Hue: 7.5YR or 10YR
Value: 4 or 6 moist; 6 or 7 dry
Chroma: 2 to 4, dry or moist
Texture: sandy loam or loamy sand
Clay content: 5 to 10 percent
Rock fragments: 45 to 85 percent
Reaction: slightly acid to neutral

AC horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 moist; 6 or 7 dry
Chroma: 2, 3, or 4, dry or moist
Texture: loamy sand
Clay content: 5 to 10 percent
Rock fragments: 45 to 85 percent
Reaction: moderately acid to neutral

COMPETING SERIES:
Clark Fork (MT) - are very deep
Hopdraw (SC) - are 100 to 150 cm to a lithic contact
Nemote (MT) - are very deep
Quamon (CO) - are very deep
Rochester (MT) - are very deep

GEOGRAPHIC SETTING:
Landform - ridgetops, mountain slopes, scarp slopes, and foothills.
Elevations - 1,220 to 1,678 meters
Slopes - 2 to 60 percent
Parent material - formed in slope alluvium or colluvium over residuum from non-calcareous sedimentary rocks
Climate - cool, with moist springs and warm summers
Mean annual temperature - 4.0 to 6.0 degrees C.
Mean annual precipitation - 480 to 610 mm.
Frost free season - 80 to 110 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; moderately rapid permeability; slow to medium runoff.

USE AND VEGETATION: Used for forest products and, to a lesser extent, rangeland. The conifer forest is dominated by ponderosa pine with an understory of arrowleaf, balsamroot, common snowberry, Saskatoon serviceberry, Idaho fescue, Columbia needlegrass, bluebunch wheatgrass, western yarrow, timothy, and sedge.

DISTRIBUTION AND EXTENT: Oraid soils are of moderate extent in the mountains and foothills of central Montana. MLRAs 43B and 46.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Fergus County, Montana, 1979.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 9cm (Oi and A1 horizons)
Particle-size control section from - 28 to 67cm (AC horizon)
Lithic contact - the zone starting at 67cm (R horizon)

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National Cooperative Soil Survey
U.S.A.