LOCATION TOQUIMA                 NV

Tentative Series
Rev. JBF-RLB-TM-JVC
11/2016

TOQUIMA SERIES

The Toquima series consists of moderately deep, well drained soils that formed in residuum and colluvium derived from volcanic rocks. Toquima soils are on mountains. Slopes are 50 to 75 percent. The mean annual precipitation is about 560 mm and the mean annual temperature is about 4 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Xeric Argicryolls

TYPICAL PEDON: Toquima very cobbly loam--forestland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 20 percent cobbles and 5 percent stones.

Oi--0 to 5 cm; slightly decomposed plant material composed of pine needles and duff; abrupt wavy boundary. (3 to 8 cm thick)

A1--5 to 10 cm; brown (10YR 5/3) very cobbly loam, dark brown (10YR 3/3) moist; thick platy structure parting to moderate fine subangular blocky; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial and common very fine and fine tubular pores; 15 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 7.0); abrupt smooth boundary. (5 to 13 cm thick)

A2--10 to 28 cm; brown (10YR 4/3) extremely cobbly loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine through course roots; common fine tubular and interstitial pores; 40 percent gravel, 20 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); clear smooth boundary. (10 to 23 cm thick)

Bt--28 to 48 cm; yellowish brown (10YR 5/4) extremely cobbly loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine through coarse roots; common fine tubular pores; common faint clay films on faces of peds and lining pores; 40 percent gravel, 30 percent cobbles, and 5 percent stones; neutral (pH 7.0); clear smooth boundary. (20 to 30 cm thick)

C--48 to 81 cm; light yellowish brown (10YR 6/4) extremely cobbly loamy coarse sand, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine, few medium and coarse roots; many fine through coarse interstitial pores; 45 percent gravel, 30 percent cobbles, and 5 percent stones; neutral (pH 7.0); abrupt wavy boundary. (25 to 50 cm thick)

R--81 cm; fractured hard tuff; roots in fractures.

TYPE LOCATION: Nye County, Nevada; on the Toiyabe National Forest and the Arc Dome Wilderness of the Toiyabe Range west of Little Jett Creek; about 2,500 feet east and 1,600 north of the southwest corner of section 36, T. 11 N., R. 41 E.; USGS Arc Dome 7.5 minute topographic quadrangle; latitude 38 degrees 46 minutes 37 seconds N and longitude 117 degrees 19 minutes 22.3 seconds W; WGS84 Decimal Degrees 38.7769444 latitude, -117.3227778 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section from late fall through late spring, dry in summer and early fall; xeric soil moisture regime.
Mean annual soil temperature: 4 to 7 degrees C.
Mean summer soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 25 to 36 cm.
Depth to base of argillic horizon: 25 to 50 cm.
Depth to bedrock: 76 to 100 cm to a lithic contact.

Particle-size control section - Clay content: 120 to 27 percent.
Rock fragments: Average 60 to 80 percent, with 0 to 10 percent stones, 20 to 35 percent cobbles, and 35 to 50 percent gravel. About 30 percent of gravel is fine (2 to 5 mm diameter). Lithology of fragments is volcanic rocks such as tuff and rhyolite.

A1 horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly acid or neutral.
Organic matter content: 3 to 5 percent.

A2 horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 5 percent.
Texture: Extremely cobbly loam, extremely cobbly sandy clay loam or extremely cobbly sandy loam.

Bt horizon
Value: 5 or 6 dry.
Chroma: 3 or 4, dry or moist.
Texture: Extremely cobbly loam or extremely cobbly sandy clay loam.

C horizon
Value: 5 or 6 dry.
Rock fragments: 70 to 90 percent.

COMPETING SERIES: These are the Boneyard, Chamberlain, Cowlow, Crandall, Ezbin, Forsey, Fourme, Itwo, Jackflat, Packer, Scuffe, Stopatoe, Tagum, Winada, and Zeebar series.

Boneyard and Itwo soils lack Oi horizons and have a depth to the base of the argillic horizon of 50 to 100 cm. Chamberlain, Ezbin, Forsey, Fourme, Jackflat, Packer and Zeebar soils are deeper than 100 cm. Cowlow soils have a calcic horizon at 28 to 76 cm. Crandall soils are deep to lithic contacts. Scuffe soils have 45 to 60 percent rock fragments in the particile-size control section. Stopatoe, Tagum, and Winada soils are moderately deep to paralithic contacts.

GEOGRAPHIC SETTING: Toquima soils are on mountains. They typically occur on backslope positions. They formed in colluvium and residuum derived from volcanic rocks. Slopes are 50 to 75 percent. Elevations range from 2,810 to 3,205 meters. The mean annual precipitation is 500 to 600 mm, mean annual temperature is 3 to 6 degrees C, and the frost-free period is 20 to 50 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Foxvire soil and the competing Packer and Stopatoe soils. Foxvire soils are very deep and have thick mollic epipedons.

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

USE AND VEGETATION: Toquima soils are used for forestland and wildlife habitat. The vegetation is a sparse forest canopy of limber pine with an understory of mainly mountain big sagebrush, snowberry, Currant ssp., Letterman's needlegrass, and spike fescue.

DISTRIBUTION AND EXTENT: Central Nevada. These soils are not extensive. MLRA 28B.

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

SERIES PROPOSED: Nye County (Toiyabe National Forest), Nevada, 1997.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Organic soil material - The zone from the soil surface to 5 cm (Oi horizon).
Mollic epipedon - The zone from the soil surface to 28 cm (Oi, A1, and A2 horizons).
Argillic horizon - The zone from 28 to 48 cm (Bt horizon).
Lithic contact - The boundary at 81 cm to underlying hard unweathered bedrock (R layer).
Particle-size control section - The zone from 28 to 48 cm (Bt horizon).

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National Cooperative Soil Survey
U.S.A.