LOCATION BIGTOP ORTentative Series
TAXONOMIC CLASS: Fine, smectitic, frigid Xeric Argialbolls
TYPICAL PEDON: Bigtop ashy sandy clay loam - supporting an herbaceous community, rangeland, on a 2 percent slope at 4890 feet elevation. (Colors are for moist soil unless otherwise noted.)
Oe--0 to 1 inch; moderately decomposed plant material; herbaceous litter; abrupt broken boundary. (0 to 1 inch thick)
Ac--1 to 15 inches; very dark grayish brown (10YR 3/2) ashy sandy clay loam, grayish brown (10YR 5/2) dry; moderate coarse subangular blocky parting to moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; common very fine and fine tubular pores, common very fine interstitial pores; 5 percent fine cylindrical brown (7.5YR 4/4) iron-manganese masses infused into matrix adjacent to pores, reddish yellow (7.5YR 6/8) dry; 3 percent indurated volcanic rock gravel, 1 percent strongly cemented iron-manganese nodule gravel, 2 percent moderately cemented iron-manganese nodule paragravel and 1 percent moderately cemented pumice paragravel; slightly acid (pH 6.2); clear wavy boundary. (4 to 16 inches thick)
AEc--15 to 23 inches; dark grayish brown (10YR 4/2) paragravelly ashy sandy clay loam, brown (10YR 5/3) dry; weak medium subangular blocky structure; moderately hard, very friable, slightly sticky, slightly plastic; many very fine and few fine roots; few very fine and many fine tubular pores, common very fine irregular pores; 5 percent indurated volcanic rock gravel, 5 percent indurated volcanic rock cobbles, 3 percent strongly cemented iron-manganese nodule gravel, 5 percent moderately cemented iron-manganese nodule paragravel and 1 percent moderately cemented pumice paragravel; slightly acid (pH 6.4); clear smooth boundary. (6 to 24 inches thick)
Ec--23 to 26 inches; dark grayish brown (10YR 4/2) gravelly ashy sandy loam, light brownish gray (10YR 6/2) dry; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky, slightly plastic; few very fine and fine roots; common very fine tubular pores; 4 percent indurated volcanic rock gravel, 5 percent indurated volcanic rock cobbles, 25 percent strongly cemented iron-manganese nodule gravel and 20 percent moderately cemented iron-manganese nodule paragravel; neutral (pH 6.6); abrupt smooth boundary. (1 to 6 inches thick)
2Btss--26 to 30 inches; brown (10YR 4/3) gravelly silty clay, brown (7.5YR 5/2) dry; strong coarse columnar structure parting to strong medium wedge and strong coarse subangular blocky; extremely hard, extremely firm, moderately sticky, very plastic; few very fine and fine roots; few fine irregular and common very fine tubular pores; many brown (7.5YR 4/4) slickensides on wedge faces and on faces of blocky peds, brown (7.5YR 5/3) dry; 10 percent coarse irregular dark gray (2.5Y 4/1) iron depletions in matrix , light gray (10YR 7/2) dry; 15 percent medium irregular black (2.5Y 2.5/1) iron-manganese masses throughout, very dark grayish brown (2.5Y 3/2) dry; 15 percent indurated volcanic rock gravel, 2 percent indurated volcanic rock cobbles and 10 percent strongly cemented iron-manganese nodule gravel; slightly acid (pH 6.4); gradual smooth boundary. (3 to 10 inches thick)
2Bqm--30 to 36 inches; olive brown (2.5Y 4/3) cemented material, yellowish brown (10YR 5/4) dry; strong thick platy structure; extremely hard, slightly rigid, very strongly cemented by silica, nonsticky, nonplastic; few very fine roots between peds; few fine irregular and common very fine tubular pores; 30 percent coarse irregular very strongly cemented black (2.5Y 2.5/1) iron-manganese nodules throughout, very dark grayish brown (10YR 3/2) dry; 80 percent fine platy very strongly cemented brown (10YR 5/3) opal with sharp boundaries on faces of peds, pink (7.5YR 7/4) dry; 5 percent indurated volcanic rock gravel; neutral (pH 6.8).
TYPE LOCATION: Klamath County, Oregon; about 2 miles north and 27 miles east of Chiloquin; about 300 feet east and 1950 feet north of the southwest corner of section 24, T. 34 S., R. 11 E.; Spodue Mountain, Oregon USGS quadrangle; 42 degrees, 36 minutes, 26.00 seconds north latitude and 121 degrees, 21 minutes, 59.00 seconds west longitude; UTM 633996 meters E, 4718282 meters N, zone 10 NAD27.
RANGE IN CHARACTERISTICS:
Soil Temperature: cryic regime
Mean annual soil temperature - 35 to 39 degrees F
Mean summer soil temperature - 39 to 43 degrees F
Mean winter soil temperature - 32 to 35 degrees F
Soil Moisture: aquic and xeric regimes; moisture control section - 4 to 12 inches, saturated in all parts for 45 to 90 days in April, May or June; dry in all parts for 60 to 90 consecutive days in August, September and October
Particle-size control section: argillic horizon
Clay content, average: 35 to 50 percent
Rock fragment content, average: 15 to 35 percent
Diagnostic horizons and features:
aquandic subgroup properties: upper boundary at the mineral soil surface, 16 to 30 inches thick
ammonium oxalate extractable Al plus 1/2 Fe: 0.2 to 0.4 percent
0.02 to 2.0 mm fraction: 30 to 50 percent of fine earth fraction
volcanic glass content: 30 to 70 percent
mollic epipedon: 10 to 29 inches thick
albic horizon: 1 to 6 inches thick
abrupt textural change: 16 to 30 inches below mineral soil surface
argillic horizon: 3 to 10 inches thick
duripan, depth below mineral soil surface: 20 to 40 inches
Ac horizon
Value: 2 or 3 moist, 3 to 5 dry
Chroma: 1 to 3 moist, 1 or 2 dry
Clay content: 20 to 30 percent
Rock fragment content: 0 to 5 percent
Gravel: 0 to 5 percent
Cobble: 0 to 1 percent
Stone: 0 to 1 percent
Pumice paragravel content: 0 to 10 percent
Reaction: moderately acid or slightly acid (pH 5.6 to 6.5)
AEc horizon
Depth to: 4 to 16 inches
Hue: 7.5YR, 10YR, or 2.5Y moist or dry
Value: 2 to 4 moist, 4 or 5 dry
Chroma: 2 or 3 moist or dry
Texture: paragravelly ashy loam, cobbly ashy loam, paragravelly ashy sandy loam, gravelly ashy sandy loam, paragravelly ashy sandy clay loam
Clay content: 12 to 25 percent
Rock fragment content: 10 to 20 percent
Gravel content: 0 to 10 percent
Cobble content: 0 to 10 percent
Stone content: 0 to 1 percent
Pumice paragravel content: 5 to 10 percent
Reaction: slightly acid or neutral (pH 6.1 to 7.3)
Ec horizon
Depth to: 10 to 29 inches
Hue: 7.5YR, 10YR, 2.5Y moist or dry
Value: 4 or 5 moist, 6 or 7 dry
Chroma: 1 or 2 dry
Texture: gravelly ashy loam, gravelly ashy sandy loam
Clay content: 10 to 20 percent
Rock fragment content: 15 to 35 percent
Gravel content: 15 to 30 percent
Cobble content: 0 to 10 percent
Stone content: 0 to 1 percent
Paragravel content: 15 to 35 percent
Reaction: slightly acid or neutral (pH 6.1 to 7.3)
2Btss horizon
Depth to: 16 to 30 inches
Hue: 7.5YR, 10YR, 2.5Y moist or dry
Value: 3 or 4 moist, 4 or 5 dry
Chroma: 2 or 3 moist, 2 to 4 dry
Texture: gravelly silty clay, gravelly clay, gravelly clay loam
Clay content: 35 to 50 percent
Rock fragment content: 15 to 35 percent
Gravel content: 10 to 25 percent
Cobble content: 0 to 10 percent
Stone content: 0 to 1 percent
Paragravel content: 0 to 15 percent
Reaction: slightly acid or neutral (pH 6.1 to 7.3)
2Bqm horizon
Depth to: 20 to 40 inches
Texture: cemented material, cemented gravelly material, cemented cobbly material
Rock fragment content: 0 to 30 percent
Gravel content: 0 to 20 percent
Cobble content: 0 to 10 percent
Stone content: 0 to 1 percent
COMPETING SERIES:
Boles (ID) - are greater than 60 inches deep, have a seasonal perched watertable with its uppermost limit at 14 to 27 inches, do not have aquandic subgroup properties and have a mean summer soil temperature of 43 to 47 degrees F.
GEOGRAPHIC SETTING:
Landscape - lava plateau and valleys
Landform - drainageways on dipslopes, hillslopes, and lava flows
Elevation - 4220 to 5720 feet
Slope - 0 to 2 percent
Parent material - alluvium over alluvium or residuum
Climate - cold moist winters and cool dry summers
Mean annual air temperature - 40 to 45 degrees F
Mean annual precipitation - 16 to 28 inches
Frost-free period - 30 to 50 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bottlespring,
Maset,
Shukash and Shortnap soils.
Bottlespring soils are well drained, have a xeric moisture regime and have an argillic horizon directly under the mollic epipedon.
Maset soils are well drained, have andic soil properties in the upper part of the particle-size control section, have 18 to 35 percent clay in lower part of the particle-size control section and are 20 to 40 inches deep to bedrock.
Shukash soils are somewhat excessively drained, have andic soil properties in the upper part of the particle-size control section, have 10 to 20 percent clay in lower part of the particle-size control section and are greater than 60 inches deep.
Shortnap soils are somewhat poorly drained, have andic soil properties in the upper part of the particle-size control section and have 10 to 18 percent clay in lower part of the particle-size control section.
DRAINAGE AND PERMEABILITY:
Drainage - poorly drained
Permeability - very slow
Watertable - a seasonal water table perched on the duripan is at its uppermost limit in April, May or June
USE AND VEGETATION: Bigtop soils are used for livestock grazing, wildlife habitat, watershed and recreation. The potential natural plant community is the dry meadow series. Common species include onespike danthonia, prairie Junegrass and Cusick's bluegrass.
DISTRIBUTION AND EXTENT: Klamath County, Oregon; MLRA 6. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Winema National Forest, Klamath County, Oregon, 2008
REMARKS: Depth to diagnostic horizons and features start from the mineral soil surface.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 1 to 15 inches (Ac and AEc horizons)
Aquic conditions with episaturation - 1 to 30 inches (Ac, AEc, Ec and 2Btss horizons)
Aquandic subgroup properties - 1 to 26 inches (Ac, AEc, and Ec horizons)
Albic horizon - 23 to 26 inches (Ec horizon)
Abrupt textural change - 26 inches (top of 2Btss horizon)
Argillic horizon - 26 to 30 inches (2Btss horizon)
Slickensides - 26 to 30 inches (2Btss horizon)
Duripan - 30 to 36 inches (2Bqm horizon)
Particle-size control section - 26 to 30 inches (2Btss horizon)
ADDITIONAL DATA:
NASIS SITE ID - 02-JFD-05; NASIS PEDON ID - 02OR683005
NSSL analysis on 1 to 4, 4 to 15 and 15 to 20 inch depth zones (Ac and AEc horizons), sample number - S02OR-035-006, sampled as: Bigtoe