LOCATION FINGERRIDGE CAEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Lithic Argixerolls
TYPICAL PEDON: Fingerridge extremely gravelly ashy loam--rangeland. (Colors are for dry soil unless otherwise noted). The soil surface is partly covered by 70 percent gravel, 10 percent cobbles and 2 percent stones.
A--0 to 6 inches; dark grayish brown (10YR 4/2) extremely gravelly ashy loam, very dark brown (10YR 2/2), moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common fine roots and few medium roots and many very fine roots; many very fine interstitial and common very fine tubular pores; 5 percent cobbles and 55 percent pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 8 inches thick)
Bt--6 to 13 inches; brown (10YR 5/3), extremely gravelly ashy loam, dark brown (10YR 3/3), moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine to medium roots; common very fine interstitial and tubular pores; 2 percent distinct clay films on all faces of peds and 2 percent distinct clay films on surfaces along pores; 5 percent cobbles and 55 percent pebbles; slightly acid (pH 6.5); abrupt irregular boundary. (4 to 9 inches thick)
R--13 inches; hard andesitic tuff bedrock.
TYPE LOCATION: Modoc County, California; on the Modoc National Forest in the Warner Mountains 800 feet north and 1300 feet east of the southwest corner of section 3, T 44N, R 15E; Payne Peak USGS 7.5 minute topographic quadrangle; 41 degrees 37 minutes 9.1 seconds north latitude and 120 degrees 15 minutes 7.9 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - These soils are usually moist in winter, spring, and early summer, dry later in summer and fall; xeric soil moisture regime.
Mean annual soil temperature - 43 to 47 degrees F.
Oxalate extractable Al + 1/2 Fe: 0.2 to 0.4 percent.
Volcanic glass content - 50 to 80 percent in the coarse silt through fine sand fractions.
Mollic epipedon thickness - 7 to 14 inches.
Depth to bedrock - 7 to 14 inches to hard bedrock. The lithic materials below the contact are andesitic tuff or tuff-breccia.
Profile reaction - Slightly acid or neutral.
Particle-size control section - Clay content: Averages 12 to 18 percent, (field estimates).
Rock fragments: 60 to 80 percent, mainly gravel. Fragment lithology is tuff or tuff-breccia.
A horizons - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 2 percent.
Bt horizon - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy loam or ashy sandy loam.
Clay content: 15 to 20 percent.
Rock fragments: 60 to 80 percent.
Structure: Moderate or strong, fine to coarse subangular blocky.
Organic matter content: 1 to 2 percent.
COMPETING SERIES: These are the Anaud, Domehill, Farepeak, Granquin, Hardnut, Schoolmarm, Skidbrackle, Starflyer, and Welltomas soils. The Anaud, Granquin, Domehill, Farepeak, Hardnut, Schoolmarm, and Starflyer soils have an aridic moisture regime. Domehill, Farepeak, Schoolmarm, and Starflyer soils have more than 18 percent clay in the control section. Hardnut and Skidbrackle soils have bedrock within 14 to 40 inches. Welltomas soils have more than 18 percent clay in the control section.
GEOGRAPHIC SETTING: Fingerridge soils are on mountains. They formed in volcanic ash and colluvium over residuum derived from glassy tuff or tuff-breccia. Slopes are 2 to 15 percent. Elevations range from 5,610 to 8,300 feet. The climate is subhumid with cold, moist winters and warm, dry summers. The mean annual precipitation is 30 to 50 inches, most of which comes as snow. The mean annual temperature is 38 to 44 degrees F. The frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Paynepeak and Pyropatti series. Paynepeak and Pyropatti soils have mollic epipedons more than 30 inches thick and have bedrock deeper than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium or high surface runoff; moderately rapid permeability.
USE AND VEGETATION: Fingerridge soils are used for watershed, wildlife habitat, and livestock grazing. The vegetation consists of low sagebrush, Idaho fescue, and bluegrass.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are not extensive. MLRA 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California and Nevada, 2005.
REMARKS: The name is coined from a local peak.
Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - The zone from the mineral soil surface to 13 inches (A and Bt horizons).
Vitrandic intergrade feature -- High volcanic glass content in the .02 to 2mm fraction from the mineral soil surface to 13 inches (A and Bt horizons).
Argillic horizon - The zone from 6 to 13 inches (Bt horizon).
Lithic contact - The boundary at 13 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 0 to 13 inches (A and Bt horizons).