LOCATION ORNEA                   ID

Established Series
Rev. CWT/ALH/CLM
03/2021

ORNEA SERIES

The Ornea series consists of very deep, well drained soils on fan terraces. They formed in mixed alluvium from lacustrine deposits and volcaniclastic materials. Permeability is moderately slow. Slopes range from 1 to 40 percent. The average annual precipitation is about 7 inches and the average annual temperature is about 51 degrees F.

TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, mesic Typic Haplargids

TYPICAL PEDON: Ornea gravelly loam -- rangeland; on a 2 percent northwest-facing slope. (When described on April 4, 1978, the profile was slightly moist in the upper 12 inches and dry below. Colors are for air dry soil unless otherwise noted.)

A--0 to 5 inches; very pale brown (10YR 7/3) gravelly loam, brown (10YR 5/3) moist; strong very fine platy structure; soft, very friable, slightly sticky; common very fine roots; common very fine tubular pores; 20 percent gravel; strongly alkaline (pH 8.9); abrupt smooth boundary. (3 to 7 inches thick)

Bt--5 to 9 inches; very pale brown (10YR 8/3) gravelly loam, pale brown (10YR 6/3) moist; moderate coarse prismatic structure; hard, firm, slightly sticky and plastic; common very fine roots; common very fine tubular pores; many moderately thick clay films on faces of peds; 15 percent gravel; slightly effervescent; strongly alkaline (pH 8.8); clear smooth boundary. (3 to 8 inches thick)

Btk--9 to 12 inches; very pale brown (10YR 7/3) gravelly clay loam, light yellowish brown (10YR 6/4) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common moderately thick clay films on faces of peds; 20 percent gravel; strongly effervescent; strongly alkaline (pH 8.7); clear wavy boundary. (0 to 6 inches thick)

2Bk--12 to 26 inches; very pale brown (10YR 7/3) very gravelly coarse sand, light yellowish brown (10YR 6/4) moist; single grain; loose; common very fine roots; 40 percent gravel; strongly effervescent; strongly alkaline (pH 8.7); gradual wavy boundary. (8 to 20 inches thick)

2C--26 to 65 inches; variegated extremely gravelly coarse sand; single grain, loose; few very fine roots; 75 percent gravel; slightly effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Elmore County, Idaho; about 5 miles east of Oreana; about 2,500 feet north and 500 feet west of the southeast corner of section 36, T.4 S., R.1 E.

RANGE IN CHARACTERISTICS:

Average annual soil temperature - 50 to 55 degrees F.
Depth to contrasting textures - 10 to 20 inches

A horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 or 3 dry or moist

Bt and Btk horizons
Value - 6 to 8 dry, 5 or 6 moist
Chroma - 2 to 4 dry or moist
Texture - GR-SCL, GR-L, or GR-CL
Reaction (pH) - mildly to strongly alkaline

2Bk and 2C horizons
Texture - GRV-LS, GRV-S, GRV-COS, GRX-LS, GRX-S, GRX-COS, CBV-S, or CBX-COS
Rock fragment content - 35 to 80 percent
Reaction (pH) - moderately or strongly alkaline

COMPETING SERIES: These are the Ethete, Garland, Hough, and Sharland series. Ethete and Garland soils are greater than 20 inches deep to contrasting textures. Hough soils have less than 35 percent rock fragments within 40 inches. Sharland soils are moist in the moisture control section for 30 to 60 days in May and June, and are dry the rest of the year.

GEOGRAPHIC SETTING: Ornea soils are on fan terraces, pediments, and valleysides at elevations of 2,300 to 4,000 feet. These soils formed in mixed alluvium from lacustrine deposits and volcaniclastic materials. Slopes are 1 to 40 percent. The average annual precipitation is 6 to 9 inches, most of which falls during winter months. The average annual temperature is 48 to 53 degrees F. The frost-free season is 120 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abgese, McKeeth, and Shoofly series. Abgese soils lack contrasting textures. McKeeth soils have a weakly cemented Bkq horizon. Shoofly soils have a duripan. These soils occur in landscape positions similar to the Oreana series.

DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability in the upper part and very rapid in the underlying material.

USE AND VEGETATION: Ornea soils are used primarily for rangeland and wildlife habitat; a few small areas are irrigated. The potential natural plant community consists mainly of shadscale, bud sagebrush, and Indian ricegrass. Crops grown include small grains, sugar beets, and alfalfa hay.

DISTRIBUTION AND EXTENT: Southwest Idaho. The soils are moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Elmore County Area, Idaho, 1986.

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

Argillic horizon - the zone from 5 to 12 inches (Bt and Btk horizons)

Particle-size control section - the zone from 5 to 40 inches (Bt, Btk, 2Bk, and part of 2C horizons)

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National Cooperative Soil Survey
U.S.A.