LOCATION HORSECAMP CA+NVEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Haploxererts
TYPICAL PEDON: Horsecamp very cobbly silty clay on a west-facing slope of 5 percent under Wyoming big sagebrush at 4,500 feet elevation. (When described on June 15, 1977, the soil was dry to 6 inches and nearly dry from 6 to 46 inches. Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; brown (7.5YR 5/2) very cobbly silty clay, dark brown (7.5YR 4/2) moist; weak very fine granular and subangular blocky structure; slightly hard, very friable, very sticky and very plastic; common very fine roots; many very fine interstitial pores; 5 percent stones; 30 percent cobbles; 20 percent pebbles; vertical cracks 2 to 5 mm wide; neutral (pH 6.8); clear wavy boundary. (1 to 6 inches thick)
Bw--2 to 6 inches; brown (10YR 5/3) silty clay, dark brown (10YR 4/3) moist; moderate medium and coarse prismatic structure parting to moderate fine and medium angular blocky; hard, very friable, very sticky and very plastic; common very fine and few fine and medium roots; common very fine tubular and interstitial pores; vertical cracks 2 to 5 mm wide; slightly effervescent; neutral (pH 7.0); clear wavy boundary. (4 to 6 inches thick)
Bss--6 to 27 inches; brown (10YR 5/3) silty clay, dark brown (10YR 4/3) moist; strong coarse and very coarse prismatic structure parting to strong coarse and very coarse angular blocky; very hard, very friable, very sticky and very plastic; few very fine, fine and medium roots on peds; common very fine tubular pores; vertical cracks 5 to 30 mm wide and 7 to 18 cm apart; few intersecting slickensides; few wedge shaped aggregates tilted 30 to 60 degrees from horizontal; 5 percent fine (2-5 mm) pebbles; slightly effervescent; neutral (pH 7.2); clear wavy boundary. (15 to 26 inches thick)
Bssk--27 to 46 inches; brown (10YR 5/3) silty clay, dark brown (10YR 4/3) moist; moderate coarse and very coarse prismatic structure parting to strong coarse and very coarse angular blocky; very hard, friable, very sticky and very plastic; few very fine and fine roots on peds, few very fine tubular pores; vertical cracks 2 to 5 mm wide; common intersecting slickensides; common wedge-shaped aggregates tilted 30 to 60 degrees from horizontal; 5 percent fine (2-5 mm) pebbles; strongly effervescent, lime segregated in few fine filaments; mildly alkaline (pH 7.4); abrupt wavy boundary. (15 to 22 inches thick)
R--46 inches; hard basalt rock with some vertical and horizontal fractures; violently effervescent, lime coatings on the faces of fractured rock. Fractures are 1/4 to 3/4 inches wide and 8 to 12 inches apart.
TYPE LOCATION: Lassen County, California; about 3.8 miles E of the Big Mud Flat on Smoke Creek Ranch Road and 1.0 mile S of this road; 1,600 feet N and 1,500 feet W of the SE corner of section 9, T.30 N., R.16 E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to a lithic contact ranges from 40 to 60 inches. The mean annual soil temperature ranges from 47 degrees to 53 degrees F. Cracks (1 to 7.5 cm wide) open and close each year and extend as deep as 40 inches or more forming large prisms. The cracks remain open during June through December for about 200 days. Few to many intersecting slickensides and tilted, wedge shaped aggregates occur at some depth between 10 and 40 inches. Cobbles and stones on the surface range from 10 to 35 percent. Depth to secondary carbonates is 20 to 35 inches. Some pedons have discontinuous indurated silica and lime cementation at the lithic contact.
The A horizon color is 10YR 5/2, 5/3; or 7.5YR 5/2. Moist color is 10YR 4/2, 4/3 or 7.5YR 4/2. It is clay or silty clay with a weighted average of 40 to 60 percent clay. The A horizon is cobbly clay, cobbly silty clay, very cobbly silty clay or very cobbly clay. Rock fragments, mostly cobbles, range from 20 to 55 percent.
The Bw horizon, is 10YR 4/3 or 5/3 modified by 0 to 10 percent gravel. They are silty clay, clay, or clay loam. Reaction is neutral through moderately alkaline. Calcium carbonate equivalent is 0 to 3 percent.
The Bk horizon is slightly to strongly effervescent, and lime is segregated in filaments, seams or threads. Calcium carbonate equivalent is 3 to 8 percent.
COMPETING SERIES: These are the Brubeck, Doten, Karcal, Manogue, Moroni, Ravendale (T), and Waspo series. Doten and Ravendale soils are moderately well drained and have water tables sometime during the year or are ponded. Brubeck soils are 20 to 40 inches deep to hard bedrock. Karcal soils are 20 to 30 inches deep to hard bedrock and have cracks that remain open for about 120 days. Manogue soils are very slowly permeable and have secondary carbonates within 20 inches of the surface. Moroni soils have cracks that remain open for 60 to 90 days and have 2.5Y hues. Ravendale soils have cracks open 60 to 120 consecutive days in the summer and fall and have carbonates below 40 inches. Waspo soils are 20 to 40 inches deep to a paralithic contact.
GEOGRAPHIC SETTING: Horsecamp soils are on plateaus. Slopes are 0 to 9 percent. The soils formed in material weathered from hard basalt or andesite. Elevations are 4300 to 5800 feet. The climate is cool semi-arid mesothermal with hot dry summers and cold moist winters. Mean annual precipitation is 9 to 12 inches. Annual snowfall is 20 to 30 inches. Mean January temperature is about 26 degrees to 30 degrees F., mean July temperature is about 66 degrees to 68 degrees F. Frost-free period is about 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Brubeck and Ravendale series and the Corral, Devada, Gerlach, Longcreek and Shinnpeak series. Corral and Devada soils have argillic horizons and are less than 20 inches deep to bedrock. Shinnpeak soils have indurated silica-cemented hardpans between depths of 12 to 20 inches. Gerlach soils are over 60 inches in depth, and have values of less than 5.5 dry and less than 3.5 moist throughout the upper 12 inches.
DRAINAGE AND PERMEABILITY: Well drained, runoff is slow to medium, slow permeability.
USE AND VEGETATION: Used mainly for rangeland and wildlife habitat. The vegetation is mainly Wyoming big sagebrush, western wheatgrass, beardless wildrye and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Lassen County, California. The soils of this series are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, California. Susanville Area, California, 1990.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from the soil surface to 2 inches (A).
Cambic horizon - the zone from 2 to 27 inches (BW1 and Bw2 horizons)
Vertical cracks at least 1 cm wide - zone from the soil surface to 46 inches (A, Bw, Bss, Bssk).
Lithic contact - boundary at 46 inches (R).
Intersecting slickensides - zone from 6 to 46 inches (Bss, Bssk).