LOCATION COWGIL                  NV+ID

Established Series
Rev. WDM/PWB/RLB/JBF
01/2019

COWGIL SERIES

The Cowgil series consists of very deep, well drained soils that formed in alluvium derived volcanic and quartzite and in some areas colluvium derived from shale, rhyolite or welded tuffs. The Cowgil soils are on fan remnants and hills. Slopes are 0 to 50 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Xeric Haplargids

TYPICAL PEDON: Cowgil very gravelly sandy loam--rangeland. (Colors are for dry soil unless otherwise noted) The soil surface is partially covered with approximately 30 percent gravel, 10 percent cobbles, and 5 percent stones.

A--0 to 8 cm; grayish brown (10YR 5/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; many fine and very fine interstitial and tubular pores; 30 percent gravel, 10 percent cobbles and 5 percent stones; slightly alkaline (pH 7.8); abrupt smooth boundary. (5 to 10 cm thick)

Bt1--8 to 20 cm; pale brown (10YR 6/3) very cobbly sandy clay loam, brown (10YR 4/3) moist; moderate fine granular structure; soft, very friable, moderately sticky and moderately plastic; many fine and very fine roots; many fine and very fine interstitial pores; few faint clay films on faces of ped; 25 percent gravel, 10 percent cobbles and 5 percent stones; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 33 cm thick)

Bt2--20 to 25 cm; pale brown (10YR 6/3) gravelly sandy clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many fine and very fine roots; many fine interstitial and tubular pores; few distinct clay films on faces of peds and lining pores; 20 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (5 to 33 cm thick)

Bt3--25 to 76 cm; pale brown (10YR 6/3) very gravelly sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable; moderately sticky and moderately plastic; many fine and very fine roots; many fine interstitial and tubular pores; few distinct clay films on faces of peds and lining pores; 35 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (0 to 50 cm thick)

2Ck--76 to 155 cm; very pale brown (10YR 7/3) very cobbly loamy sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; common fine roots; many fine and medium interstitial pores; 30 percent gravel, 15 percent cobbles and 5 percent stones; slightly effervescent; moderately alkaline (pH 8.4).

TYPE LOCATION: Elko County, Nevada; approximately 1,750 feet west and 750 feet south of the northeast corner of section 22, T. 40 N., R. 55 E.: USGS Mahala Creek East 7.5 minute topographic quadrangle; latitude 41 degrees 21 minutes 04 seconds N and longitude 115 degrees 45 minutes 38 seconds W; WGS84 Decimal Degrees 41.3511111 latitude, -115.7605556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, but moist in winter and spring, dry summer and fall; aridic bordering on xeric soil moisture regime.
Mean annual soil temperature: 8 to 12 degrees C.
Depth to base of the argillic: 50 to 76 cm.

Particle-size control section - Clay content 20 to 35 percent.
Rock fragments: 35 to 60 percent, mostly gravel, but includes cobbles and stones.

A horizon
Value: 5 through 7 dry; 3 through 5 moist.
Chroma: 2 through 4 dry, 2 or 3 moist.
Reaction: Slightly alkaline or moderately alkaline.

Bt horizons
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Gravelly or very gravelly sandy clay loam in the upper subhorizon and very gravelly or extremely gravelly sandy clay loam in the lower subhorizons. Some pedons have subhorizons of very gravelly loam or very gravelly clay loam.
Structure: Very fine through medium subangular blocky, prismatic, granular or is massive in lower subhorizon.
Clay films: Few to common.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Noneffervescent or slightly effervescent in the lower subhorizon.

2Ck horizons
Value: 5 through 8 dry, 4 through 7 moist.
Chroma: 2 through 4 dry, 3 through 5 moist.
Texture: Coarse sand, loamy sand, or sand.
Clay content: 2 to 10 percent.
Rock fragments: 45 to 70 percent, gravel and cobbles.
Reaction: Slightly alkaline through strongly alkaline.
Effervescence: Slightly effervescent through strongly effervescent.
Calcium carbonate equivalent: 0 to 3 percent.
Other features: Some pedons have secondary silica or secondary calcium carbonate coats on rock fragments. Some pedons have few weakly cemented secondary calcium carbonate masses on rock fragments.

COMPETING SERIES: These are the Bairs, Basket, Breko, Chiefrange, Drino, Hefed, Huilepass, Hunewill, Jungo, Kayo, Lithgow, Plush, Schader, Stucky, and Washoe series.

Bairs soils have 10 to 18 percent clay in the particle-size control section and have a mean annual soil temperature of 11 to 15 degrees C. Basket, Breko and Chiefrange soils receive 10 to 20 days of summer precipitation. The Drino, Lithgow, and Schader soils are less than 100 cm deep to bedrock. The Hefed, Huilepass, and Hunewill soils have a combined thickness of the A and Bt horizons that is less than 50 cm. Jungo soils have combined thickness of A and B horizons of more than 100 cm, have Btk horizons at depths of 13 to 25 cm, contain carbonates coating on rocks at 13to 25 cm and have mean annual soil temperatures greater than 12 degrees C. Kayo soils have 13 to 18 percent clay in the particle-size control section. Plush and Stucky soils have neutral argillic horizons and lack Bk horizon beneath the argillic. Washoe soils are slightly acid or neutral and do not have a Ck horizon of secondary calcium carbonate accumulation.

GEOGRAPHIC SETTING: Cowgil series are on fan remnants and hills. These soils formed in mixed alluvium derived from volcanic and quartzite sources and in some areas colluvium derived from shale, rhyolite or welded tuffs. Slopes are 0 to 50 percent. Elevations are 1,680 to 2,080 meters in Nevada and are 750 to 1,050 meters in Idaho. The climate is cool, semiarid with cool, moist winters and hot, dry summers. The mean annual precipitation is 200 to 250 mm; mean annual temperature is 8 to 10 degrees C. and 9 to 11 degrees C. in Idaho, and the frost-free season is normally 100 to 130 days and ranges up to 140 days in Idaho.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Yody and Bylo soils. Yody soils have a duripan within a depth of 100 cm. The Bylo series has a cambic horizon.

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

USE AND VEGETATION: Cowgil soils are used for livestock grazing and wildlife habitat. The present vegetation is Wyoming big sagebrush, Douglas rabbitbrush, Indian ricegrass, bottlebrush squirreltail, and cheatgrass.

DISTRIBUTION AND EXTENT: Northeastern Nevada and southwestern Idaho. These soils are not extensive. MLRA 25 and 28B.

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

SERIES ESTABLISHED: Elko County, Nevada, Central Part, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 8 cm (A horizon)
Argillic horizon - The zone from 8 to 76 cm (Bt1, Bt2 and Bt3 horizons).
Particle-size control section - The zone from 8 to 58 cm (Bt1, Bt2 and the upper part of the Bt3 horizon).

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National Cooperative Soil Survey
U.S.A.