LOCATION IGERT                   ID

Established Series
Rev. JR/ALH/CLM
01/2019

IGERT SERIES

The Igert series consists of moderately deep, well drained soils with moderately slow permeability that formed in residuum and slope alluvium from welded rhyolitic tuff and breccia. Igert soils are on structural benches and foothills. Slopes range from 2 to 20 percent. The average annual precipitation is about 280 mm and the annual temperature is about8 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Durinodic Xeric Haplargids

TYPICAL PEDON: Igert gravelly loam -- on a west-facing convex slope of 6 percent, in native rangeland at 1,610 meters elevation. (When described on July 16, 1980, the soil was dry to 25 cm, slightly moist between 25 and 50 cm and dry below. Colors are for air-dry soils unless otherwise stated.)

A1--0 to 10 cm; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; weak fine platy structure parting to moderate fine granular; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine, few medium roots; many fine and very fine interstitial and vesicular pores; 20 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (5 to 13 cm thick)

A2--10 to 30 cm; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine, common medium, few coarse roots; common fine and very fine tubular and interstitial pores; 15 percent gravel; neutral (pH 7.3); gradual smooth boundary. (0 to 20 cm thick)

BA--30 to 46 cm; yellowish brown (10YR 5/4) gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many fine and very fine, common medium and coarse roots; many fine and very fine tubular pores; 15 percent gravel; neutral (pH 7.3); clear wavy boundary. (0 to 18 cm thick)

Bt--46 to 58 cm; light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine, very fine and medium roots; many fine and very fine, few medium tubular and interstitial pores; many faint clay films on faces of peds and in pores; 20 percent gravel, 5 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (13 to 25 cm thick)

Bkq--58 to 99 cm; very pale brown (10YR 7/3) discontinuous weakly cemented very gravelly loam, yellowish brown (10YR 5/4) moist; massive; hard, firm, nonsticky and nonplastic; few fine and very fine roots; common fine and very fine interstitial pores; 50 percent gravel, 5 percent cobbles; strong effervescence; moderately alkaline (pH 7.9); abrupt irregular boundary. (10 to 66 cm thick)

R--99 cm; fractured welded rhyolitic tuff with common, moderately thick silica and calcium carbonate coatings in fractures.

TYPE LOCATION: Owyhee County, Idaho; about 16 miles west and 11 1/2 miles north of Grasmere; 900 feet north and 550 feet east of the southwest corner of section 3, T.10 S., R.3 E.; USGS Hill Pasture 7.5 minute topographic quadrangle; 42 degrees, 34 minutes, 52 seconds North Latitude and 116 degrees, 05 minutes, 52 seconds West Longitude; WGS84 Decimal Degrees 42.5811111 latitude, -116.0977778 longitude.

RANGE IN CHARACTERISTICS:

Depth to calcium carbonates - 30 to 58 cm.
Depth to bedrock - 64 to 100 cm.
Average annual soil temperature - 8 to 11 degrees C.
Aridic moisture regime bordering on xeric.

A horizon
Value - 6 or 7 dry, 3 or 4 moist
Chroma - 2 through 4 dry or moist
Reaction (pH) - neutral or slightly alkaline
Rock fragments - 0 to 25 percent

Bt horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 through 6 dry or moist
Texture - CL, GR-L, or GR-CL
Clay content - 25 to 35 percent
Rock fragments - 10 to 25 percent
Reaction (pH) - neutral through moderately alkaline

Bkq horizon
Hue - 7.5YR or 10YR
Value - 5 to 7 dry, 5 or 6 moist
Chroma - 3 or 4 dry or moist
Texture - GRX-L, GRV-L, or GR-L
Clay content - 12 to 20 percent
Rock fragments - 30 to 90 percent
Calcium carbonate equivalent - 5 to 15 percent
Reaction (pH) - moderately or strongly alkaline
Cementation - commonly weakly or strongly cemented durinodes and occasionally thin discontinuous indurated laminae

COMPETING SERIES: These are the Alley, Allor, Bedke, Cath, Chime, Glyphs, Nevador, Wedertz, Wedlar and Zevadez series. All of these soils except Chime soils are deeper than 100 cm to bedrock. Chime soils lack secondary calcium carbonates and are over a paralithic contact at 50 to 75 cm.

GEOGRAPHIC SETTING: Igert soils are undulating to hilly on convex summits and sideslopes of structural benches and foothills at elevations of 945 to 1,650 meters. Slopes range from 2 to 20 percent. These soils formed in residuum and slope alluvium from welded rhyolitic tuff and breccia. The climate is cool and moist in winter and hot and dry in summer. Average annual precipitation ranges from 250 to 330 mm. Average annual temperature ranges from 7 to 10 degrees C. Frost-free period is 90 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bruncan, Hardtrigger, Snowmore and Willhill series. Bruncan soils are shallow over a duripan on gently sloping positions. Hardtrigger soils are more than 100 cm deep and on lower concave positions. Snowmore soils have a continuous duripan and are on similar positions. Willhill soils have more than 35 percent rock fragments in the control section and are on similar positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow to rapid runoff; moderately slow saturated hydraulic conductivity.

USE AND VEGETATION: Igert soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is Wyoming big sagebrush, bluebunch wheatgrass, Sandberg bluegrass, and bottlebrush squirreltail.

DISTRIBUTION AND EXTENT: Southwestern Idaho. Igert soils are moderately extensive. MLRA 25.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.

REMARKS: This revision (8/95) changes the classification from Durixerollic Haplargids to Durinodic Xeric Haplargids according to the 1994 edition of Keys to Soil Taxonomy. The remainder of the OSD has not been updated since 5/93.

Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - zone 0 to 46 cm (A1, A2 and AB horizons).
Argillic horizon and particle-size control section - zone 18 to 23 inches (Bt horizon).
Lithic contact - The boundary at 99 cm (R layer).
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.

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National Cooperative Soil Survey
U.S.A.