LOCATION PEQUOP                  NV

Established Series
Rev. JVC/JBF
12/2022

PEQUOP SERIES

The Pequop series consists of very deep, well drained soils that formed in colluvium and residuum derived from rhyolite, tuff, and similar volcanic rocks. Pequop soils are on hills, mountains, and fan remnants. Slopes are 8 to 50 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 Typic Argixerolls

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

A1--0 to 10 cm; dark grayish brown (10YR 4/2) gravelly loam, black (10YR 2/1) moist; moderate fine and medium subangular blocky structure; parting to weak fine granular, soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; 15 percent gravel; neutral (pH 6.8); clear smooth boundary. (8 to 20 cm thick)

A2--10 to 30 cm; brown (10YR 4/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine, few medium tubular pores; 25 percent gravel; neutral (pH 7.0); clear smooth boundary. (17 to 30 cm thick)

Bt1--30 to 48 cm; brown (7.5YR 5/4) extremely gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; many very fine and fine, few medium roots; many fine and medium tubular pores; common distinct clay films on faces of peds and lining pores; 65 percent gravel; neutral (pH 7.0); clear smooth boundary. (13 to 28 cm thick)

Bt2--48 to 71 cm; yellowish red (5YR 5/6) very gravelly sandy clay loam, reddish brown (5YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine and fine, few medium roots; many very fine and fine tubular pores; many distinct clay films on faces of peds and lining pores; 50 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (18 to 28 cm thick)

Bt3--71 to 104 cm; reddish brown (5YR 5/4) extremely gravelly sandy clay loam, reddish brown (5YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and moderately plastic; common very fine, fine and medium roots; many very fine and fine tubular pores; common distinct clay films on faces of peds and lining pores; 20 percent cobbles and 45 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (28 to 40 cm thick)

Bt4--104 to 127 cm; brown (7.5YR 5/4) very gravelly clay loam, dark brown (7.5YR 3/4) moist; weak fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine, fine and medium pores; few distinct clay films on faces of peds and lining pores; 10 percent cobbles and 40 percent gravel; neutral (pH 7.2); clear smooth boundary. (18 to 28 cm thick)

Bk--127 to 152 cm; yellowish brown (10YR 5/4) very gravelly loam, dark yellowish brown (10YR 4/4) moist; massive; hard, firm, slightly sticky and slightly plastic; many fine and medium tubular pores; secondary carbonates segregated as common coats on bottoms of rock fragments and few fine masses and filaments; 15 percent cobbles and 40 percent gravel; neutral (pH 7.2).

TYPE LOCATION: Elko County, Nevada; about 8 miles south-southeast of Midas; about 800 feet south and 2,500 feet west of the northeast corner of section 8, T. 37 N., R. 46 E., USGS Sixmile Hill 7.5 minute topographic quadrangle; 41 degrees 06 minutes 16 seconds north latitude and 116 degrees 48 minutes 25 seconds west longitude, WGS84 Decimal Degrees 41.1044444 latitude, -116.8069444 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry mid-July through October; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 25 to 50 cm, includes the Bt1 horizon in some pedons.
Depth to base of argillic horizon: 40 to 60 cm.
Reaction: Neutral or slightly alkaline.

Particle-size control section - Clay content: 20 to 35 percent;
Rock fragments: 40 to 70 percent, dominantly gravel. Lithology of fragments are volcanic rocks such as rhyolite and tuff.

A horizons
Value: 3 through 5 dry, 2 through 4 moist.
Chroma: 1 through 3, dry or moist.
Organic matter content: 2 to 5 percent.

Bt horizons
Hue: 5YR through 10YR.
Value: 3 through 5 moist, 5 or 6 dry.
Chroma: 3 through 6 dry, 3 or 4 moist.
Texture: Very gravelly sandy clay loam, extremely gravelly sandy clay loam, or very gravelly clay loam with less than 35 percent silt.
Clay content: 20 to 35 percent.
Rock fragments: 40 to 70 percent, dominantly gravel.
Structure: Very fine, fine, or medium subangular blocky.
Organic matter content: 1 to 3 percent.

Bk horizon (when present)
Value: 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly loam or extremely gravelly loam.
Rock fragments: 40 to 80 percent, dominantly gravel with cobbles dominant in a few pedons.

COMPETING SERIES: These are the Clanalpine, Devaul, Elaero, Glideski, Heechee, Heenlake, Holmes, Horrocks, Hoskin, Howcan, Longday, Moreypeak, Suak, Valmar, Vitale, and Wambolt series.

Clanalpine, Elaero, Heenlake, Moreypeak, Suak, and Vitale soils are moderately deep to paralithic contacts. Devaul soils are deep to paralithic contacts. Heechee soils have the base of the argillic horizon at 69 to 100 cm from the soil surface. Glideski and Wambolt soils are moist in the upper part of the moisture control section for 10 to 20 cumulative days from precipitation received between July and October. Holmes soils have the base of the argillic horizon at 41 to 81 cm from the soil surface and have sandy textures within 100 cm of the soil surface. Horrocks soils are deep to lithic contacts. Hoskin and Valmar soils are moderately deep to lithic contacts. Howcan soils have the base of the argillic horizon at 64 to 100 cm from the soil surface. Longday soils have more than 60 percent rock fragments throughout the argillic horizons and lack secondary carbonates.

GEOGRAPHIC SETTING: Pequop soils are on hills, mountains, and fan remnants. They typically occur of north-facing backslope positions. These soils formed in colluvium and residuum derived from rhyolite, tuff, and similar volcanic rocks. Slopes are 8 to 50 percent. Elevations range from 1,525 to 2,505 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 330 to 380 mm, mean annual temperature is 5 to 7 degrees C, and the frost-free period is 75 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bregar, Bucan, Chen, Ninemile, and Quarz soils. Bregar are very shallow and shallow to lithic contacts and have ochric epipedons. Bucan soils are fine, deep to lithic contacts, and have ochric epipedons. Chen soils are clayey-skeletal and shallow to lithic contacts. Ninemile soils are clayey and shallow to lithic contacts. Quarz soils are clayey-skeletal and moderately deep to lithic contacts. In addition, all of these soils have an aridic moisture regime.

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

USE AND VEGETATION: Pequop soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly mountain big sagebrush, Idaho fescue, Sandberg's bluegrass, basin wildrye, bluebunch wheatgrass, and lanceleaf rabbitbrush.

DISTRIBUTION AND EXTENT: Northeastern Nevada. These soils are moderately extensive. MLRA 25.

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

SERIES ESTABLISHED: Elko County (Northeast Part), Nevada, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 30 cm (A1 and A2 horizons).
Argillic horizon - The zone from 30 to 127 cm (Bt1, Bt2, Bt3, and Bt4 horizons).
Identifiable secondary carbonates - The zone from 127 to 150 cm (Bk horizon).
Particle-size control section - The zone from 30 to 80 cm (Bt1 and Bt2 horizons and part of the Bt3 horizon).

ADDITIONAL DATA: Previous authors and editors include: RWD-TSB-RLB.

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National Cooperative Soil Survey
U.S.A.