LOCATION CEWAT                   NV+CA

Established Series
Rev. EWB-WED-JVC-JBF
12/2022

CEWAT SERIES

The Cewat series consists of moderately deep, well drained soils that formed in alluvium and colluvium derived from volcanic rocks. Cewat soils are on beach terraces and rock pediments. Slopes are 4 to 15 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 11 degrees C.

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

TYPICAL PEDON: Cewat extremely cobbly fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 13 cm; light brownish gray (10YR 6/2) extremely cobbly fine sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; 2 percent stones, 45 percent cobbles, and 40 percent gravel; neutral (pH 7.0); clear smooth boundary. (8 to 15 cm thick)

A2--13 to 18 cm; light brownish gray (10YR 6/2) very gravelly fine sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 2 percent stones, 10 percent cobbles, and 25 percent gravel; neutral (pH 7.0); clear smooth boundary. (3 to 10 cm thick)

Bw1--18 to 46 cm; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine through coarse roots; common very fine and fine tubular pores; 25 percent gravel; neutral (pH 7.0); clear wavy boundary. (13 to 30 cm thick)

Bw2--46 to 69 cm; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular pores; 5 percent cobbles and 45 percent gravel; neutral (pH 7.0); clear wavy boundary. (0 to 30 cm thick)

Bk--69 to 89 cm; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common fine interstitial pores; 15 percent cobbles and 60 percent gravel; strongly effervescent; secondary carbonates segregated as common pendants on bottoms of rock fragments; slightly alkaline (pH 7.5); abrupt irregular boundary. (0 to 50 cm thick)

R--89 cm; hard basalt; with discontinuous coats of secondary carbonate.

TYPE LOCATION: Washoe County, Nevada; in the east end of Honey Lake Valley about 0.75 mile east of the California-Nevada state line; about 490 feet north and 600 feet west of the southeast corner of section 29, T. 28 N., R. 18 E.; USGS Parker Canyon 7.5 minute topographic quadrangle; latitude 40 degrees 15 minutes 40.9 seconds N and longitude 119 degrees 58 minutes 55.6 seconds W; WGS84 Decimal Degrees 40.2613611 latitude, -119.982111 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry in summer and fall; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 12 to 15 degrees C.
Depth to bedrock: 50 to 100 cm to a lithic contact.

Particle-size control section - Clay content: 15 to 25 percent;
Rock fragments: Averages 35 to 75 percent, mainly gravel. Lithology of fragments is volcanic rocks such as basalt.

A horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral or slightly alkaline.
Identifiable secondary carbonates: None or few pendants on bottoms of rock fragments.

Bw horizons
Chroma: 3 or 4, dry or moist.
Clay content: 15 to 25 percent.
Rock fragments: 35 to 75 percent; subhorizons range from 25 to 90 percent.
Reaction: Neutral through moderately alkaline.
Effervescence: Noneffervescent in the Bw1 horizon, may be slightly effervescent in the Bw2 horizon.

Bk horizon (when present)
Value: 6 or 7 dry.
Chroma: 3 or 4, dry or moist.
Clay content: 15 to 20 percent.
Rock fragments: 35 to 85 percent.
Reaction: Slightly alkaline through strongly alkaline.
Effervescence: Strongly effervescent or violently effervescent.
Identifiable secondary carbonates: Occur as pendants on bottoms of rock fragments, as filaments, or as masses.
Calcium carbonate equivalent: 0 to 2 percent.
Other features: Some pedons with bedrock at depths of less than 30 inches lack secondary carbonates, but the lithic contact will be at least partially coated in these pedons.

COMPETING SERIES: These are the Darkcanyon, Drinkwater, Lonegrave, Finley, Kiona, Minat, Nibbs, Veet, Veta, and Wifton series.

Darkcanyon soils have 25 to 35 percent clay in the particle-size control section, are dominated by channers and flagstones of schist and graywacke, and have mean annual soil temperature of 9 to 12 degrees C. Lonegrave soils have mean annual soil temperature of 8 to 10 degrees C. Drinkwater, Finley, Kiona, Minat, Nibbs, Veet, Veta, and Wifton soils are very deep.

GEOGRAPHIC SETTING: Cewat soils are on beach terraces and rock pediments. They are adjacent to margins of plateaus that were inundated by Pleistocene lakes. These soils formed in colluvium and residuum derived from volcanic rocks. Slopes are 4 to 15 percent. Elevations range from 1,265 to 1,340 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 250 mm, the mean annual temperature is 10 to 12 degrees C, and the frost-free period is 90 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buffaran and Jaybee soils. Buffaran soils are clayey, shallow to duripans, and have argillic horizons. Jaybee soils are very shallow and shallow to lithic contacts and have argillic horizons.

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

USE AND VEGETATION: Cewat soils are used for rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, spiny hopsage, and bottlebrush squirreltail.

DISTRIBUTION AND EXTENT: Northwestern Nevada and northeastern California. These soils are not extensive with about 6,900 acres of the series mapped to date. MLRAs 23 and 27.

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

SERIES ESTABLISHED: Washoe County (Central Part), Nevada, 1990.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A1 and A2 horizons).
Cambic horizon - The zone from 18 to 69 cm (Bw1 and Bw2 horizons).
Identifiable secondary carbonates - The zone from 69 to 89 cm (Bk horizon).
Lithic contact - The boundary at 89 cm to underlying hard, unweathered bedrock (R layer).
Particle-size control section - The zone from 25 to 89 cm (Bw2 and Bk horizons and part of the Bw1 horizon).

The revision of March 2007 updated the typical pedon by adding another A horizon to accommodate the surface cover of more than 80 percent rock fragments as the new soil surface.

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National Cooperative Soil Survey
U.S.A.