LOCATION VERDICO                 NV+CA

Established Series
Rev. EWB-JBF-TM-JVC
06/2017

VERDICO SERIES

The Verdico series consists of moderately deep, well drained soils that formed in alluvium, colluvium, and residuum derived from water-laid tuff. Verdico soils are on plateaus, hills, strath terraces, and rock pediments. Slopes are 4 to 30 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Paleargids

TYPICAL PEDON: Verdico very stony sandy loam--rangeland. (Colors are for dry soil unless otherwise noted).

A--0 to 5 cm; pale brown (10YR 6/3) very stony sandy loam, brown (10YR 4/3) moist; weak medium platy structure; soft, very friable, slightly sticky and slightly plastic; few fine tubular pores, common medium vesicular pores; 15 percent gravel, 15 percent cobbles, and 15 percent stones; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 13 cm thick)

Bt1--5 to 38 cm; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; strong medium prismatic structure, extremely hard, very firm, very sticky and very plastic; common fine and very fine and few medium roots; few fine tubular pores; common prominent clay films or pressure cutans on faces of peds; 5 percent gravel and 5 percent cobbles; neutral (pH 6.6); clear wavy boundary. (23 to 40 cm thick)

Bt2--38 to 56 cm; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; weak coarse prismatic structure; very hard, very firm, moderately sticky and moderately plastic; few fine and common medium roots; few fine tubular pores; common prominent clay films on faces of peds; 10 percent gravel; neutral (pH 7.0); gradual wavy boundary. (10 to 25 cm thick)

2C--56 to 74 cm; light yellowish brown (10YR 6/4) gravelly clay, yellowish brown (10YR 5/4) moist; massive; very hard, very firm, moderately sticky and moderately plastic; few fine and medium roots; few fine tubular pores; 25 percent gravel; slightly alkaline (pH 7.5); gradual wavy boundary. (0 to 36 cm thick)

2Cr--74 cm; highly fractured, water-laid tuff with some carbonates and silica in fractures.

TYPE LOCATION: Washoe County, Nevada; in northwest Reno east of McCarran Boulevard and north of Skyline Drive; approximately 2,100 feet north and 200 feet east of the southwest corner of section 27, T. 19 N., R. 19 E.; USGS Mount Rose NE 7.5 minute topographic quadrangle; latitude 39 degrees 28 minutes 54 seconds N and longitude 119 degrees 50 minutes 42 seconds W; WGS84 Decimal Degrees 39.4816667 latitude, -119.8450000 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: 8 to 11 degrees C.
Depth to base of argillic horizon: 43 to 76 cm.
Depth to bedrock: 50 to 100 cm to a paralithic contact. The paralithic materials below the contact are weathered and fractured water-laid tuffaceous sedimentary rocks.
Other features: An abrupt horizon boundary is normally present between the A and Bt1 horizons accompanied by an abrupt increase in clay content of at least 20 percent.
Linear extensibility (LE): 6 to 9 cm.

Particle-size control section - Clay content: 45 to 60 percent.
Rock fragments: 0 to 10 percent gravel.

A horizon
Value: 5 or 6 dry; 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly acid or neutral.

Bt horizons
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Structure: Weak through strong prismatic.
Reaction: Slightly acid through slightly alkaline
Other features: Common or many pressure cutans are in most pedons.

C horizon (when present)
Value: 6 or 7 dry, 4 or 5 moist.
Texture: Gravely clay loam or gravelly clay.
Clay content: 35 to 50 percent.
Rock fragments: 15 to 30 percent.
Reaction: Neutral or slightly alkaline.
Identifiable secondary carbonates: None to few fine filaments and masses.

COMPETING SERIES: There are the Borda, Campo, Gooding, Mahala, Phing, Sorf, and Twickenham series.

Borda, Campo, Gooding, Phing, Sorf, and Twickenham soils lack bedrock within a depth of 100 cm. Mahala soils have secondary carbonates in the argillic horizon within a depth of 36 to 76 cm.

GEOGRAPHIC SETTING: Verdico soils are on plateaus, hills, strath terraces, and rock pediments. These soils formed in alluvium, colluvium, and residuum derived from water-laid tuff and similar tuffaceous sedimentary rocks. Slopes are 4 to 30 percent. Elevations range from 1,375 to 2,170. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm, the mean annual temperature is 9 to 10 degrees C, and the frost-free period is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chalco, Indian Creek, Leviathan, and Stodick soils. Chalco soils are less than 50 cm deep. Indian Creek soils have an indurated duripan at a depth of less than 50 cm deep. Leviathan soils have less than 35 percent clay in the particle-size control section and are deep. Stodick soils have more than 35 percent rock fragments in the particle-size control section.

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

USE AND VEGETATION: Verdico soils are used for urban development, rangeland, and wildlife habitat. Native vegetation is mainly low sagebrush, Douglas rabbitbrush, horsebrush, and bottlebrush squirreltail.

DISTRIBUTION AND EXTENT: Western Nevada and northeastern California. These soils are moderately extensive. The series concept and main acreage is in MLRA 26, while other acreage occurs in MLRA 23.

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

SERIES ESTABLISHED: Washoe County (South Part), Nevada, 1980.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 5 cm (A horizon).
Argillic horizon - The zone from 5 to 56 cm (Bt1 and Bt2 horizons).
Vertic subgroup feature - A linear extensibility of 6 cm or more between the soil surface and the paralithic contact.
Paleargid great group feature - There is an abrupt textural change at 5 cm with a clay increase of 20 percent or more (absolute) within 2.5 cm at the upper boundary of the argillic horizon (between the A and Bt1 horizons).
Paralithic contact - The boundary at 74 cm to underlying weathered bedrock (2Cr layer).
Particle-size control section - The zone from 5 to 55 cm (Bt1 and part of the Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.