LOCATION TORRO                   NV

Established Series
Rev: ELS/CEJ/JBF
12/2019

TORRO SERIES

The Torro series consists of very deep, well drained soils that formed in residuum and colluvium derived from cherts and shales with an admixture of loess and volcanic ash. The Torro soils are on mountain side slopes. Slopes are 15 to 75 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Aridic Argixerolls

TYPICAL PEDON: Torro very gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 15 cm; grayish brown (10YR 5/2) very gravelly loam, very dark brown (10YR 2/2) moist; weak medium and coarse subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine roots; many very fine and few fine tubular pores; 45 percent angular gravel; neutral (pH 6.6); clear smooth boundary. (10 to 25 cm thick)

A2--15 to 33 cm; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate very fine and fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; common very fine and fine interstitial, few medium and fine tubular pores; 40 percent angular gravel; neutral (pH 6.6); abrupt wavy boundary. (8 to 20 cm thick)

Bt--33 to 64 cm; light yellowish brown (10YR 6/4) extremely gravelly clay loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine roots; many very fine and fine, common medium tubular pores; 65 percent angular gravel; few faint clay films in pores and bridging and coating sand grains; neutral (pH 6.6); clear smooth boundary. (25 to 60 cm thick)

C1--64 to 84 cm; pale brown (10YR 6/3) extremely gravelly coarse sandy loam, brown (10YR 4/3) moist; weak medium and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many fine and common medium interstitial pores; 60 percent angular gravel, 10 percent cobbles; neutral (pH 6.6); gradual smooth boundary. (5 to 28 cm thick)

C2--84 to 127 cm; pale brown (10YR 6/3) extremely gravelly coarse sandy loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine and fine, few medium interstitial pores; 65 percent angular gravel; neutral (pH 6.6).

TYPE LOCATION: Elko County, Nevada; approximately 28 miles northwest of Elko, approximately 2,900 feet east and 650 feet south of the apparent northwest corner of section 18, T. 37 N., R. 51 E.; USGS Beaver Peak 7.5 minute topographic quadrangle; latitude 41 degrees 6 minutes 11 seconds N and longitude 116 degrees 17 minutes 17 seconds W; WGS84 Decimal Degrees 41.1030556 latitude, -116.2880556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Dry from July to mid October, moist in some part mid-October through June; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 25 to 40 cm.
Combined thickness of A and Bt horizons: 60 to 100 cm.

Particle-size control section - Clay content: 20 to 30 percent.
Rock fragments: 60 to 75 percent, mainly angular chert and shale pebble-sized fragments.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3.
Structure: Weak or moderate, very fine to coarse subangular blocky or platy or very fine and fine angular.

Bt horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4.
Texture: Extremely gravelly loam, clay loam, or sandy clay loam.
Structure: Weak or moderate, fine or medium, angular or subangular blocky.
Consistence: Slightly hard or hard dry, very friable or friable moist, sticky or very sticky and slightly plastic or plastic wet. Clay films: Few or common, thin or moderately thick lining
pores, bridging and coating sand grains, or coating ped faces.

C horizons
Value: 5 or 6 moist.
Chroma: 3 or 4.
Texture: Sandy loam or loamy sand, modified by extremely gravelly.

COMPETING SERIES: These are the Belate, Burnborough, Closkey, Devils, Gowjai, Granipeak, Jivas, Millan and Sumine series.

Belate and Burnborough soils have mollic epipedons that include the upper Bt horizon and have Bt horizons with 35 to 60 percent rock fragments. Closkey soils have a lithic contact between 50 to 90 cm. Devils soils have a paralithic contact between 50 and 90 cm and have Bt horizons with 35 to 60 percent rock fragments. Gowjai and Granipeak soils have 35 to 60 percent rock fragments in the argillic horizon. Jivas soils have a combined A and Bt horizon thickness of 100 to 150 cm directly overlaying hard bedrock. Millan soils are intermittently moist in the upper part for 10 to 20 days cumulative due to convection storms between July and September Sumine soils have mollic epipedons that include the upper Bt horizon and have a lithic contact between 50 and 100 cm.

GEOGRAPHIC SETTING: Torro soils are on south-facing mountain side slopes. These soils formed in colluvium and residuum derived dominantly from chert and shale with an admixture of loess and volcanic ash. Slopes are 15 to 75 percent. Elevations are 1,980 to 2,500 meters. The climate is cool, continental with warm, dry summers and cold, moist winters. The mean annual precipitation is 300 to 400 mm; mean annual temperature is 5 to 6 degrees C, and the frost-free season is 70 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jack Creek, Packer, Slaven and Tusel soils.

Jack Creek soils have a very gravelly loamy coarse sand particle-size control section. Packer and Tusel soils have cryic soil temperature regimes. Slaven soils have very gravelly clay B2t horizons and have bedrock at depths of 50 to 90 cm.

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

USE AND VEGETATION: Livestock grazing and wildlife habitat. The present vegetation is mainly mountain big sagebrush, gray rabbitbrush, antelope bitterbrush, bluebunch wheatgrass, basin wildrye, and Sandberg bluegrass.

DISTRIBUTION AND EXTENT: North-central Nevada. These soils are moderately extensive. MLRA 25.

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

SERIES ESTABLISHED: Elko County, Nevada, Tuscarora Mountain Area.
area, 1974.

REMARKS: Torro soils were formerly classified as Chestnut soils.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 33 cm (A1 and A2 horizons).
Argillic horizon - The zone from 33 to 64 cm (Bt horizon).
Particle-size control section - The zone from 33 to 64 cm (Bt horizon).

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National Cooperative Soil Survey
U.S.A.