LOCATION UDAHO              ID

UDAHO SERIES

TAXONOMIC CLASS: Ashy-skeletal, glassy, mesic Vitrixerandic Haplocalcids

TYPICAL PEDON: Udaho very gravelly loam - on a southeast facing slope of 28 percent under sagebrush and bunchgrass at 5,700 feet elevation. (Colors are for dry soil unless otherwise noted.) When described on 6-78 the soil profile was slightly moist to 18 inches and dry below.

A--0 to 7 inches; pale brown (10YR 6/3) very gravelly loam, dark brown (10YR 4/3) moist; weak fine granular structure; slightly hard, firm; many, very fine, fine, medium, and common coarse roots; very fine and fine tubular pores; 35 percent gravel; slightly effervescent; mildly alkaline (pH 7.6); gradual wavy boundary. (4 to 10 inches thick)

Bk1--7 to 14 inches; very pale brown (10YR 7/3) very gravelly loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, firm; many roots; 50 percent gravel, mostly duripan fragments; strongly effervescent (16 percent calcium carbonate); moderately alkaline (pH 8.4); clear wavy boundary. (7 to 20 inches thick)

Bk2--14 to 31 inches; very pale brown (10YR 7/3) very gravelly loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, firm; few coarse roots; 45 percent gravel size duripan and tuff fragments; strongly effervescent (19 percent calcium carbonate); moderately alkaline (pH 8.4); clear wavy boundary. (9 to 18 inches thick)

Cr--31 to 60 inches; very pale brown (10YR 8/3) partially weathered volcanic ash, pale yellow (2.5Y 7/4) moist; massive; extremely hard, extremely firm; few coarse roots; slightly effervescent.

TYPE LOCATION: Twin Falls County, Idaho, about 15 miles south of Rogerson, in the southeast 1/4, northeast 1/4, northeast 1/4 section 32, T. 16 S., R. 16 E.

RANGE IN CHARACTERISTICS:

Depth to secondary lime - 6 to 15 inches
Thickness of solum - 11 to 30 inches
Depth to partially consolidated ash (paralithic) - 20 to 40 inches Clay content in control section - 10 to 20 percent
Average annual soil temperature - 48 to 50 degrees F.

A horizon
Value - 5 or 6 dry, 3 through 5 moist
Chroma - 2 or 3
Gravel - 35 to 45 percent
Structure, shape - granular or platy
pH - mildly alkaline or moderately alkaline

Bk horizon
Value - 5 through 8 dry, 3 through 6 moist
Chroma - 2 through 4
Texture - GRV-SL, GRV-L
Gravel - 35 to 50 percent
Cobbles - 0 to 10 percent
Structure, shape - subangular blocky, massive
Calcium carbonate percent - 15 to 30
pH - moderately alkaline or strongly alkaline

Cr horizon
Hue - 2.5Y or 10YR
Value - 7 or 8 dry, 5 through 7 moist
Chroma - 1 through 4
Effervescence - slight to strong

COMPETING SERIES: These are the Darkbull, Hiko Peak, Nekiver, Sitar, and Waycup series. Darkbull, Hiko Peak, and Sitar soils are deep. Nekiver soils are moderately deep to lithic material. Waycup soils have an extremely stony loam Bw horizon, and are deep to basalt bedrock.

GEOGRAPHIC SETTING: Udaho soils occur on hillslopes and breaks. The slope ranges from 10 to 65 percent. The soils formed in colluvium from welded tuff and residuum from welded ash. Elevations range from 5,000 to 6,000 feet. The average annual precipitation ranges from 10 to 13 inches. The average annual temperature is 45 to 48 degrees. The frost free season is 100 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ackett, Arbidge, Chuska, Lankbush, and Weash soils. Ackett and Chuska soils occur on terraces, and are shallow to a hardpan. Arbidge soils occur on terraces, and are moderately deep to a hardpan. Lankbush soils occur on stream terraces, are very deep, and well drained. Weash soils occur below Udaho soils on the landscape with slopes of 2 to 12 percent, have a fine loamy control section, and are shallow to ash.

DRAINAGE AND PERMEABILITY: Well drained, medium or rapid runoff; moderately rapid permeability.

USE AND VEGETATION: Udaho soils are used for rangeland. Native vegetation is bluebunch wheatgrass, bottlebrush squirreltail, Thurber needlegrass, Indian ricegrass, arrowleaf balsamroot, Wyoming big sagebrush, antelope bitterbrush, and rabbitbrush.

DISTRIBUTION AND EXTENT: Udaho soils are of small extent in south central Idaho.

MLRA OFFICE RESPONSIBLE: Reno, Nevada

SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 7 inches (A horizon)

Calcic horizon - the zone from 7 to 31 inches (Bk1 and Bk2
horizons)

Paralithic contact - the zone from 31 to 60 inches (Cr horizon)