LOCATION TUSK                    NV

Established Series
Rev. MZ-TSB-TM-JBF
05/2016

TUSK SERIES

The Tusk series consists of very deep, well drained soils formed in colluvium derived from rhyolite and other volcanic rocks. They are on mountains, hills, and plateaus. Slopes are 8 to 50 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Argixerolls

TYPICAL PEDON: Tusk gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 10 percent gravel, 5 percent cobbles and 2 percent stones.

A1--0 to 5 cm; brown (10YR 5/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak very thin platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; common very fine tubular pores; 10 percent gravel and 5 percent cobbles; neutral (pH 7.2); clear smooth boundary. (5 to 10 cm thick)

A2--5 to 13 cm; brown (10YR 5/3) loam, very dark brown (10YR 2/2) moist; moderate very thin platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; common very fine tubular pores; 10 percent gravel, neutral (pH 7.2); clear smooth boundary. (5 to 23 cm thick)

A3--13 to 36 cm; brown (10YR 4/3) loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, few fine and medium roots; common very fine tubular pores; 10 percent gravel, neutral (pH 7.2); clear smooth boundary. (0 to 25 cm thick)

Bt1--36 to 58 cm; brown (10YR 4/3) clay loam; very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and few fine and medium roots; common very fine tubular pores; several krotovinas less than 15 millimeters in size; few faint clay films on faces of ped and lining pores; 10 percent gravel, neutral (pH 7.2); clear irregular boundary. (15 to 38 cm thick)

Bt2--58 to 97 cm; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine tubular pores; common faint clay films on faces of ped and lining pores; 15 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (8 to 15 cm thick)

Bt3--97 to 152 cm; very pale brown (10YR 7/4) extremely gravelly loam, dark yellowish brown (10YR 3/4) moist; massive; slightly hard; friable, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine and fine tubular pores; few clay films on rock fragment surfaces; 40 percent gravel and 25 percent cobbles; slightly alkaline (pH 7.4).

TYPE LOCATION: Elko County, Nevada; approximately 7 miles west of Midas, about 1,400 feet east and 750 feet north of the southwest corner of section 9, T. 39 N., R.45 E.; USGS Snowstorm Mountain 7.5 minute topographic quadrangle; latitude 41 degrees 16 minutes 00 seconds N and longitude 116 degrees 54 minutes 26 seconds W; WGS84 Decimal Degrees 41.2666667 latitude, -116.9072222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry from mid-July to October; xeric soil moisture regime.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 50 to 89 cm. Includes the upper part of the argillic horizon.
Depth to base of the argillic horizon: 100 to over 150 cm.
Reaction: Neutral or slightly alkaline.

Particle-size control section - Clay content: 27 to 35 percent.
Rock fragments: 15 to 35 percent, mainly gravel.

A horizon
Value: 2 or 3 moist.
Chroma: 2 or 3.

Bt horizons
Value: 4 through 7 dry, 3 or 4 moist.
Chroma: 2 through 4.
Texture: The upper part is clay loam and gravelly clay loam, with a mixed average of gravelly clay loam. Lower subhorizons are very gravelly clay loom to extremely cobbly loam.

COMPETING SERIES: These are the Bull, Carey Lake, Hades, Hurryback, Krueger, Lagnaf, Mahogan, Marotz, Moffspring, Nagle, Needapepper, Sag and Strom series.

Bull soils have bedrock at 100 to 152 cm. Carey Lake soils have argillic horizons less than 76 cm thick and contain less than 15 percent gravel size fragments. Mahogan soils are moderately deep to bedrock. Hades soils have an average annual soil temperature of 4 to 6 degrees C. and A1 horizons that are 50 to 97 cm thick. Hurryback soils are slightly acid to neutral and the argillic horizon contains less than 35 percent rock fragments in all parts. Krueger soils have less than 15 percent rock fragments in B2t horizons and are dry 45 to 60 days following the summer solstice. Lagnaf soils have mollic epipedons that are 89 to 127 cm thick and are dry for less than 90 days. Marotz and Sag soils are more than 50 cm deep to the argillic horizon. Moffspring soils have argillic horizon that are less than 41 cm thick, and is underlain by sand and gravel at moderate depth that contain 35 to 65 percent coarse fragments. Nagle soils are calcareous at depths of 43 to 56 cm. Strom series contain mottles at 30 to 45 cm and is saturated with water during the winter, spring and early summer, and have a water table at 61 cm.

GEOGRAPHIC SETTING: Tusk soils are on mountains, hills and plateaus. They formed in colluvium from rhyolite, other volcanic rocks and minor amounts of sedimentary rocks. Slopes are 8 to 50 percent. Elevations are 1,680 to 2,535 meters. The climate is cool, semiarid with cold, moist winters and warm, dry summers. The mean annual precipitation is 300 to 410 mm, mean annual temperature is 6 to 8 degrees C, and the frost-free season is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cleavage and Hackwood soils. The Cleavage soil is shallow to bedrock. The Hackwood soil lack argillic horizons.

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

USE AND VEGETATION: Rangeland and wildlife habitat. The vegetation is principally mountain big sagebrush, rabbitbrush, snowberry and Idaho fescue.

DISTRIBUTION AND EXTENT: Northeast Nevada. MLRA 25, 24. The series is of small extent.

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

SERIES ESTABLISHED: Elko County (Northwest part), Nevada, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (pachic) - The zone from the soil surface to 58 cm (A1, A2, A3 and Bt1 horizons).
Argillic horizon - The zone from 36 to 150 cm (Bt1, Bt2 and Bt3 horizons).
Particle-size control section - The zone from 36 to 86 cm (Bt1 and part of Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.