LOCATION SKIDBRACKLE CA OR

Established Series
JBF/EWB/TM/CEG
01/2022

SKIDBRACKLE SERIES

The Skidbrackle series consists of shallow, well drained soils that formed in volcanic ash and colluvium over residuum derived from andesite, tuff-breccia and tuff. Skidbrackle soils are on mountains, deflation basins, dip slopes, scarps, gorges, and canyons. Slopes are 2 to 30 percent. The mean annual precipitation is about 35 inches and the mean annual temperature is about 38 degrees F.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Lithic Argixerolls

TYPICAL PEDON: Skidbrackle very gravelly ashy sandy loam--rangeland. (Colors are for dry soil unless otherwise noted). The soil surface is partly covered by 45 percent gravel and 10 percent cobbles.

A1--0 to 1 inches; brown (10YR 5/3) crushed very gravelly ashy sandy loam, dark brown (10YR 3/3) crushed moist; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; common very fine roots; common very fine interstitial pores; 5 percent cobbles and 45 percent pebbles; slightly acid, (pH 6.3); clear smooth boundary. (1 to 5 inches thick)

A2--1 to 4 inches; grayish brown (10YR 5/2) crushed very gravelly ashy loam, very dark brown (10YR 2/2) crushed moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; common fine roots and many very fine roots; common very fine interstitial and tubular pores; 10 percent cobbles and 45 percent pebbles; slightly acid, (pH 6.4); clear wavy boundary. (0 to 5 inches thick)

Bt1--4 to 10 inches; brown (10YR 4/3) crushed extremely gravelly ashy loam, very dark grayish brown (10YR 3/2) crushed moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky, moderately plastic; many very fine and fine roots; common very fine interstitial and tubular pores; 15 percent faint clay bridges between sand grains; 15 percent cobbles and 55 percent pebbles; slightly acid, (pH 6.5); clear wavy boundary. (4 to 8 inches thick)

Bt2--10 to 15 inches; brown (10YR 5/3) crushed extremely gravelly ashy loam, very dark grayish brown (10YR 3/2) crushed moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky, slightly plastic; common very fine to medium roots; common very fine interstitial and tubular pores; 15 percent faint clay films on surfaces along pores and 15 percent faint clay films on faces of peds; 15 percent cobbles and 55 percent pebbles; neutral, (pH 6.6); abrupt wavy boundary. (4 to 8 inches thick)

R--15 inches; hard andesite.

TYPE LOCATION: Modoc County, California; on the Modoc National Forest in the Warner Mountains; 2,300 feet north and 800 feet west of the southeast corner of section 33, T 48N., R 16E.; Mount Bidwell USGS 7.5 minute topographic quadrangle; 41 degrees 59 minutes 11 seconds north latitude and 120 degrees 7 minutes 59 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 - 41 to 46 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 - 14 to 20 inches.
Depth to bedrock - 14 to 20 inches to hard bedrock. The lithic materials below the contact are pyroclastic tuff-breccia or andesite.
Profile reaction - Slightly acid or neutral.

Particle-size control section - Clay content: Averages 18 to 27 percent, (field estimates).
Rock fragments: 60 to 80 percent, mainly gravel and cobbles. Fragment lithology is mostly andesitic tuff, tuff-breccia and andesite.

A horizons - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Fine-earth texture: ashy sandy loam, ashy loam
Clay content: 8 to 18 percent.
Rock fragments: 10 to 75 percent.
Organic matter content: 1 to 10 percent.

Bt horizon - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Fine-earth texture: Ashy loam or ashy sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 45 to 80 percent.
Structure: Moderate or strong, fine to coarse subangular blocky.
Organic matter content: 0.5. to 2 percent.

COMPETING SERIES: These are the Fingerridge, Notellumcreek, Starflyer, and Welltomas soils. Fingerridge and Welltomas soils have bedrock within 14 inches. Notellumcreek soils have 30 to 40 percent volcanic glass content in the 0.2 to 2.0 mm fraction and average 0.05 to 0.09 percent Oxalate extractable Al + 1/2 Fe. Starflyer soils have an aridic moisture regime and have more than 27 percent clay in the control section.

GEOGRAPHIC SETTING: Skidbrackle soils are on mountains. They formed in volcanic ash and colluvium over residuum derived from andesite, tuff-breccia and tuff. Slopes are 2 to 30 percent. Elevations range from 4,920 to 8,200 feet. The climate is subhumid with cold, moist winters and warm, dry summers. The mean annual precipitation is 18 to 50 inches, most of which comes as snow. The mean annual temperature is 38 to 45 degrees F. The frost-free period is 30 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Gurlidawg, Paynepeak, and Pyropatti series. These soils all have paralithic material that occurs below 20 inches.

DRAINAGE AND PERMEABILITY: Well drained; medium or high surface runoff; moderately rapid permeability.

USE AND VEGETATION: Skidbrackle soils are used for watershed, wildlife habitat, and livestock grazing. The vegetation consists of bluegrass, Idaho fescue, low sagebrush, and mountain big sagebrush.

DISTRIBUTION AND EXTENT: Northeastern California and southern Oregon. These soils are not extensive. MLRA 21.

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

SERIES ESTABLISHED: Lake County, Oregon, Southern Part, 2006. The soil was originally proposed in Surprise Valley-Home Camp Area, California and Nevada, 2005.

REMARKS: The name was coined.
Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - The zone from the mineral soil surface to 15 inches (A1, A2, Bt1 and the Bt2 horizons).
Vitrandic intergrade feature -- High volcanic glass content in the .02 to 2mm fraction from the mineral soil surface to 31 inches (A1, A2 and the Bt horizons).
Argillic horizon - The zone from 4 to 15 inches (Bt horizon).
Lithic contact - The boundary at 15 inches to underlying soft weathered bedrock (Cr layer).
Particle-size control section - The zone from 4 to 15 inches (Bt horizons).

12/2021 - updated competing series section and expanded ranges of characteristics, following mapping of additional acreage of this soil in the Fremont portion of the Fremont-Winema National forest in Oregon.

National Cooperative Soil Survey
U.S.A.