LOCATION CROCAN                  NV+CA

Established Series
Rev. SES-JBF-TM-JVC
12/2019

CROCAN SERIES

The Crocan series consists of shallow, well drained soils that formed in residuum derived from basalt, andesite, and tuff. Crocan soils are on plateaus. Slopes are 2 to 15 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Clayey, smectitic, frigid Aridic Lithic Argixerolls

TYPICAL PEDON: Crocan very stony loam--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 15 percent stones and boulders, 15 percent cobbles and 20 percent gravel.

A1--0 to 3 cm; very dark brown (10YR 2/2) very stony loam, black (10YR 2/1) moist; moderate very fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine roots; many very fine interstitial pores; 15 percent stones, 15 percent cobbles, and 20 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 or 5 cm thick)

A2--3 to 8 cm; very dark grayish brown (10YR 3/2) very cobbly loam, very dark brown (10YR 2/2) moist; moderate very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial pores; 10 percent stones, 15 percent cobbles, and 20 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 to 8 cm thick)

Bt--8 to 13 cm; very dark grayish brown (10YR 3/2) clay loam, very dark brown (10YR 2/2) moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine, many and fine, common medium roots; common fine tubular pores; common distinct clay films on faces of peds and lining pores; 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (5 to 18 cm thick)

Btss1--13 to 25 cm; brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; strong fine and medium angular blocky structure; very hard, very friable, very sticky and very plastic; common very fine, few fine, medium and coarse roots; common very fine tubular pores; common distinct and prominent clay films on faces of peds and lining pores; vertical cracks 2 to 5 millimeters wide and 10 to 15 cm apart; common slickensides; 10 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (5 to 18 cm thick)

Btss2--25 to 36 cm; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) moist; strong medium prismatic structure parting to strong medium and coarse angular blocky; very hard, firm, very sticky and very plastic; common very fine and fine roots; common very fine tubular pores; many dark brown (10YR 3/3) distinct and prominent clay films on faces of peds and lining pores; vertical cracks 2 to 5 millimeters wide and 10 to 15 cm apart; common slickensides; 10 percent gravel; neutral (pH 7.0); abrupt irregular boundary. (0 to 15 cm thick)

R--36 cm; hard massive vesicular basalt; few fractures.

TYPE LOCATION: Washoe County, Nevada; about 5 miles southeast of Barrel Springs and south of the Barrel Springs road along power line; approximately 1,700 feet west and 2,000 feet north of the southeast corner of section 31, T. 46 N., R. 19 E.; USGS Crooks Meadow 7.5 minute topographic quadrangle; latitude 41 degrees 51 minutes 47 seconds N and longitude 119 degrees 53 minutes 33 seconds W; WGS84 Decimal Degrees 41.8630556 latitude, -119.8925000 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring; usually dry from July through October. Dry more than half the time that the soil temperature is above 5 degrees C; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 18 to 36 cm; includes all or parts of the argillic horizon.
Depth to bedrock: 25 to 36 cm to a lithic contact.

Particle-size control section - Clay content: Averages 35 to 45 percent.
Rock fragments: averages 10 to 35 percent, mainly cobbles. Lithology of fragments is mainly basalt.

A horizons
Value: 2 or 3 dry, 2 or 3 moist.
Chroma: 1 or 2, dry or moist.
Clay content: 12 to 18 percent.
Organic matter content: 5 to 10 percent in the A1 horizon, 3 to 5 percent in the A2 horizon.

Bt horizon
Hue: 7.5YR or 10YR.
Value: 3 or 4 dry, 2 or 3 moist.
Clay content: 33 to 40 percent.
Rock fragments: 5 to 15 percent, mainly gravel.
Organic matter content: 1 to 3 percent.

Btss horizons
Hue: 7.5YR or 10YR.
Value: 3 through 5 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Clay content: 55 to 65 percent.
Rock fragments: 5 to 10 percent, mainly gravel.
Organic matter content: 1 or 2 percent.
Slickensides: Occurs as few or common, small polished surfaces at bases of prisms or blocks.
Other features: Few or common vertical cracks 5 to 10 mm wide.

COMPETING SERIES: This is the Madeline series.

Madeline soils have A horizons with 4 percent or less organic matter and they do not have slickensides.

GEOGRAPHIC SETTING: Crocan soils are on plateaus. They typically occur on summit positions adjacent to rims. These soils formed in residuum derived from basalt, andesite, and tuff. Slopes are 2 to 15 percent. Elevations range from 1,650 to 2,075 meters. The climate is semiarid with cold, moist winters and warm, dry summers. The mean annual precipitation is 300 to 400 mm, the mean annual temperature is 6 to 7 degrees C, and the frost-free period is 60 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Madeline and Ninemile soils and the Tinpan soil. Tinpan soils are very-fine and moderately deep to lithic contacts.

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

USE AND VEGETATION: Crocan soils are used for livestock grazing, wood production, and wildlife habitat. The present vegetation is a forest canopy of western juniper with an understory of low sagebrush, Cusick's bluegrass, Nevada bluegrass, Idaho fescue, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Northwestern Nevada and northeastern California. These soils are moderately extensive. MLRA 23.

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

SERIES ESTABLISHED: Washoe County (North Part), Nevada, 1995.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 cm (The A1, A2, Bt, and Btss1 horizons).
Argillic horizon - The zone from 8 to 36 cm (The Bt, Btss1 and Btss2 horizons).
Slickensides - The zone from 13 to 36 cm (The Btss1 and Btss2 horizons).
Lithic contact - The boundary at 36 cm to underlying hard bedrock (The R contact).
Particle-size control section - The zone from the soil surface to 36 cm (A1, A2, Bt, Btss, and Btss2 horizons).

Classification was updated to 11th edition on 07/2011 changed from Lithic Argixerolls to Aridic Lithic Argixerolls.

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National Cooperative Soil Survey
U.S.A.