LOCATION GERLACH CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Haploxererts
TYPICAL PEDON: Gerlach silty clay--on a 5 percent west-facing slope under basin big sagebrush at 4,400 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on May 26, 1977, the soil was dry to 36 inches and was slightly moist below 36 inches.)
A--0 to 3 inches; dark grayish brown (10YR 4/2) silty clay, very dark grayish brown (10YR 3/2) moist; strong very fine granular structure; soft, very friable, very sticky and very plastic; few very fine and fine roots; common very fine interstitial pores; vertical cracks about 2.5 cm wide; neutral (pH 6.7); clear smooth boundary. (1 to 3 inches thick)
Bss1--3 to 14 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; strong coarse prismatic structure; very hard, very friable, very sticky and very plastic; common very fine, fine, medium and coarse roots; common very fine and fine tubular pores; vertical cracks about 1 cm wide; few small intersecting slickensides; neutral (pH 6.6); abrupt wavy boundary. (9 to 13 inches thick)
Bss2--14 to 36 inches; brown (7.5YR 5/2) silty clay, dark brown (7.5YR 3/2) moist; strong coarse prismatic structure; very hard, friable, very sticky and very plastic; few very fine and fine and common medium roots; common very fine and few fine tubular pores; vertical cracks about 1 cm wide; few small intersecting slickensides; neutral (pH 7.0); gradual wavy boundary. (18 to 24 inches thick)
Bss3--36 to 44 inches; brown (7.5YR 4/4) silty clay, dark yellowish brown (10YR 3/4) moist; moderate coarse angular blocky structure; hard, friable, very sticky and very plastic; few very fine and fine roots; common very fine and fine tubular pores; vertical cracks about 1 cm wide; few small intersecting slickensides; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 10 inches thick)
BC--44 to 52 inches; light yellowish brown (10YR 6/4) silty clay, dark yellowish brown (10YR 4/4) moist; weak coarse angular blocky structure; slightly hard, friable, very sticky and very plastic; few very fine roots; many very fine and common fine tubular pores; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 10 inches thick)
BCk--52 to 60 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak coarse angular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few very fine roots; many very fine and few fine interstitial and common very fine tubular pores; strongly effervescent; secondary carbonates segregated in many fine masses; moderately alkaline (pH 8.0).
TYPE LOCATION: Lassen County, California; on Mud Flat north of Honey Lake Valley; found by going about 3 miles northeast of Highway 395 along the Smoke Creek Ranch Road, then about 0.7 miles northwest along a dirt road; about 650 feet west and 800 feet south of the northeast corner of section 11, T. 30 N., R. 15 E.; USGS Shaffer Mountain 7.5 minute topographic quadrangle; 40 degrees 28 minutes 52 seconds north latitude and 120 degrees 15 minutes 01 second west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section in winter and spring, dry in summer and fall; adjacent soils have an aridic moisture regime that borders on xeric.
Mean annual soil temperature - 50 to 53 degrees F.
Mollic epipedon thickness - 30 to 40 inches.
Cracks- 1 to 7.5 cm wide, reversible trans-horizon cracks open and close once each year and extend from the soil surface to a depth of about 44 inches, forming large prisms. The cracks remain open from June through mid-December for about 200 days.
Other vertic features - Few to common intersecting slickensides occur at depths of 5 to 44 inches; Some pedons have common wedge-shaped peds at depths of 5 to 36 inches.
Depth to horizons with identifiable secondary carbonates - 40 to 60 inches.
Other features - Some pedons have up to 20 percent cobbles and a few stones on the soil surface.
A horizon - Dry color: 10YR 4/2 or 5/2; 7.5YR 4/2 or 5/2.
Moist color: 10YR 3/2 or 7.5YR 3/2.
Texture: Silty clay, clay, cobbly silty clay, or cobbly clay.
Clay content: 40 to 60 percent.
Rock fragments: 0 to 30 percent, mainly cobbles.
Organic matter content: 1 or 2 percent.
Bss1 and Bss2 horizons - Dry color: 10YR 4/2, 5/2, 5/3, 5/4; 7.5YR 4/2, 5/2, 5/3.
Moist color: 10YR 3/2 or 3/3; 7.5YR 3/2 or 3/3.
Texture: Silty clay or clay.
Clay content: 40 to 60 percent.
Organic matter content: 1 or 2 percent.
Reaction: Neutral through moderately alkaline.
Bss3 and BC horizons - Dry color: 10YR 5/3, 6/4, 6/3; 7.5YR 4/4, 5/4, 6/4.
Moist color: 10YR 3/3, 3/4, 4/3, 4/4 or 7.5YR 3/4 or 4/4.
Texture: Silty clay or clay.
Clay content: 40 to 60 percent.
Organic matter content: 0.5 to 1 percent.
Reaction: Neutral through moderately alkaline.
BCk horizon - Dry color: 10YR 6/4, 6/3, 5/3 or 7.5YR 6/4.
Moist color: 10YR 4/3, 4/4, 3/3 or 7.5YR 4/4.
Texture: Clay loam, silty clay, or clay and is crudely stratified.
Clay content: 35 to 60 percent.
Reaction: Neutral through moderately alkaline.
Calcium carbonate equivalent: 0 to 3 percent.
Gypsum content: 0 to 1 percent.
COMPETING SERIES: These are the Brubeck, Doten, Getrail, Horsecamp, Manogue, Moroni, and Waspo series.
Brubeck soils are moderately deep to lithic contacts. Doten soils have identifiable secondary carbonates within 40 inches of the soil surface and have endosaturation within 60 inches of the soil surface. Getrail soils are deep to paralithic contacts. Horsecamp soils are deep to lithic contacts. Manogue soils have free carbonates and are effervescent within 20 inches of the soil surface. Moroni soils have identifiable secondary carbonates within 20 inches of the soil surface. Waspo soils are moderately deep to paralithic contacts.
GEOGRAPHIC SETTING: Gerlach soils are on alluvial fans and stream terraces. These soils formed in alluvium derived from volcanic rocks such as tuff and basalt. Slopes are 2 to 9 percent. Elevation ranges from 4,400 to 5,000 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 9 to 12 inches including 20 to 40 inches of annual snowfall. The mean January temperature is 26 to 30 degrees F. and the mean July temperature is 66 to 68 degrees F. The mean annual temperature is 45 to 49 degrees F. The frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Brubeck and Horsecamp soils and the Corral, Devada, Ravendale, and Shinnpeak soils. Corral soils are loamy, have ochric epipedons and argillic horizons, and are shallow to paralithic contacts. Devada soils are clayey, have mollic epipedons and argillic horizons, and are shallow to lithic contacts. Ravendale soils have ochric epipedons and have cracks that remain open during July through October for about 60 to 120 days. Shinnpeak soils are loamy-skeletal, have ochric epipedons and argillic horizons, and are shallow to indurated duripans.
DRAINAGE AND PERMEABILITY: Well drained; high or very high surface runoff; slow permeability.
USE AND VEGETATION: Gerlach soils are used for rangeland and wildlife habitat. The vegetation is mostly basin big sagebrush, western wheatgrass, beardless wildrye, and Thurber's needlegrass.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are moderately extensive. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Lassen County (Susanville Area Soil Survey), California, 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 36 inches (A, Bss1, and Bss2 horizons).
Slickensides - The zone from 3 to 44 inches (Bss1, Bss2, and Bss3 horizons).
Identifiable secondary carbonates - The zone from 52 to 60 inches (BCk horizon).
Particle-size control section - The zone from 10 to 40 inches (Bss2 horizon and parts of the Bss1 and Bss3 horizons).