LOCATION COOLYORK CA
Established Series
REV: JWH/ET
07/2016
COOLYORK SERIES
The Coolyork series consists of very deep, moderately well drained soils formed in residuum and colluvium derived from chloritic schist, mudstone and sandstone. Coolyork soils are on mountains and slopes range from 5 to 75 percent. The mean annual precipitation is about 1500 mm and the mean annual air temperature is about 13 degrees C.
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Oxyaquic Argixerolls
TYPICAL PEDON: Coolyork loam on a southwest facing slope of 25 percent under a mixed forest of Oregon white oak, California buckeye, and Douglas-fir with an annual grass understory. (Colors are for dry soil unless otherwise stated) When described of June 4, 2003 the soil was moist throughout.
A--0 to 10 centimeters; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; strong medium granular structure; moderately hard, very friable, slightly sticky and slightly plastic; common very fine roots throughout; 7 percent angular gravel; slightly acid (pH 6.3); abrupt smooth boundary. (5 to 50 centimeters thick)
BAt--10 to 36 centimeters grayish brown (2.5Y 5/2) clay loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and moderately plastic; common fine and very fine roots throughout; common very fine tubular pores; very many distinct clay films on faces of peds and lining pores; 3 percent angular gravel; moderately acid (pH 6.0); abrupt smooth boundary. (0 to 30 centimeters thick)
Bt1--36 to 58 centimeters; grayish brown (2.5Y 5/2) clay loam, olive gray (5Y 4/2) moist; weak very coarse prismatic structure parting to weak medium subangular blocky; extremely hard, firm, moderately sticky and very plastic; common very fine, fine, and medium roots throughout; common very fine tubular pores; 3 percent angular gravel; moderately acid (pH 5.7); clear wavy boundary.
Bt2--58 to 108 centimeters; light brownish gray (2.5Y 6/2) clay loam, dark gray (5Y 4/1) moist; weak coarse subangular blocky structure; extremely hard, firm, moderately sticky and very plastic; few very fine and medium roots throughout; few very fine tubular pores; common faint clay films and pressure faces on faces of peds; 12 percent angular gravel; few coarse distinct olive brown (2.5Y 4/3) iron-manganese masses; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the Bt horizons is 40 to 130 centimeters)
C1--108 to 140 centimeters; grayish brown (2.5Y 5/2) gravelly loam, dark gray (5Y 4/1) moist; massive; extremely hard, firm, moderately sticky and very plastic; few very fine and medium roots throughout; few very fine tubular pores; 16 percent angular gravel; few coarse distinct olive brown (2.5Y 4/3) iron-manganese masses; slightly alkaline (pH 7.5); clear wavy boundary.
C2--140 to 180 centimeters; grayish brown (2.5Y 5/2) gravelly silt loam, dark gray (5Y 4/1) moist; massive; extremely hard, firm, moderately sticky and very plastic; few medium roots throughout; 23 percent angular gravel; moderately alkaline (pH 8.0); clear wavy boundary. (Combined thickness of the C horizons is 50 to 100 centimeters thick)
TYPE LOCATION: Humboldt County, California; about 2.5 kilometers northeast of the town of Garberville; USGS 7.5 minute topographic quadrangle Garberville, California; WGS84 -124.2244444 latitude and -123.7763889 longitude; UTM Zone 10 433846mE 4441266mN; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section, in normal years, is dry in all parts for 45 or more consecutive days in the 4 months following the summer solstice and moist in all parts for 45 or more consecutive days in the 4 months following the winter solstice. The soils have a xeric soil moisture regime.
Soil Temperature: The mean annual soil temperature at 50 centimeters is 10 to 14 degrees C. The difference between mean summer and mean winter temperature is 6 degrees C or greater. The soil has a mesic soil temperature regime
Surface Fragments: 0 to 25 percent gravel and 0 to 5 percent cobbles
Mollic epipedon: 25 to 50 centimeters thick
Depth to redoximorphic features: 50 to 100 centimeters
Particle size control section (weighted average):
Pararock fragments: 0 to 10 percent paragravel
Rock fragments: 0 to 10 percent gravel, 0 to 5 percent cobbles
Clay content: 35 to 45 percent
A horizons
Hue: 10YR or 2.5Y
Value: 4 or 5, 2 or 3 moist
Chroma: 1 to 4, 1 to 3 moist
Rock fragments: 0 to 14 percent gravel
Clay content: 18 to 27 percent
Reaction: moderately to slightly acid
Bt horizons
Hue: 10YR or 5Y
Value: 4 to 6, 2 to 4 moist
Chroma: 1 to 4, 1 to 3 moist
Texture of fine earth: clay loam, silty clay loam, silty clay, and clay
Rock fragments: 0 to 30 percent gravel
Pararock fragments: 0 to 20 percent
Clay content: 32 to 45 percent
Reaction: moderately to slightly acid
Redoximorphic Features: fine and medium iron-manganese masses
Quantity: few to many
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 3 to 8
Redoximorphic features: fine and medium iron depletions
Quantity: none to common
Hue: 2.5Y or 5Y
Value: 4 or 5
Chroma: 1 or 2
C horizons
Hue: N, 2.5Y or 5Y
Value: 4 to 6, 2 to 4 moist
Chroma: 0 to 3, moist or dry
Texture of fine earth: loam, clay loam, silt loam, clay
Rock fragments: 0 to 50 percent gravel, 0 to 5 percent cobbles
Pararock fragments: 0 to 59 percent mudstone paragravel
Clay content: 20 to 45 percent
Reaction: neutral to moderately alkaline
Redoximorphic Features: fine and medium iron-manganese masses
Quantity: none to common
Hue: 10YR or 2.5Y
Value: 4 through 6
Chroma: 3 through 8
Redoximorphic features: fine and medium iron depletions
Quantity: none to common
Hue: 2.5Y or 5Y
Value: 4 or 5
Chroma: 1 or 2
COMPETING SERIES: This is the
Coburg series. Coburg soils formed in clayey mixed alluvium and are on stream terraces. Coburg soils have mollic horizons greater than 50 centimeters thick.
GEOGRAPHIC SETTING: Coolyork soils are on mountain slopes. Slopes are 5 to 75 percent. Elevations are 60 to 1200 meters. These soils are derived from chloritic schist, mudstone, and sandstone. Coolyork soils are on linear and concave positions on mountain slopes and in drainage areas, and often have hummocky relief. The climate is subhumid with warm, dry summers and cool, wet winters. Mean annual precipitation is 1250 to 2280 millimeters. Mean January temperature is about 7 degrees C, mean July temperature is about 21 degrees C, and the mean annual temperature is 10 to 14 degrees C. Frost free season is about 220 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Tannin,
Yorknorth, and
Burgsblock soils. Tannin and Burgsblock soils contain less than 35 percent clay in the particle size control section and are on linear to concave or convex mountain slopes. Burgsblock soils contain more than 35 percent coarse fragments in the control section and are on linear to convex mountain slopes. Yorknorth soils have a mean annual soil temperature of 15 degrees C or greater and occur under grassland vegetation on linear and concave positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained, high to very high runoff, moderately low saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for commercial timber production, wildlife habitat, and watershed. Natural vegetation includes Oregon white oak, California, buckeye, tanoak, madrone, and Douglas-fir, with an understory of annual and perennial grasses.
DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Humboldt County, CA, 2010. Source of the name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Mollic epipedon - the zone from 0 to 36 centimeters (A and BAt horizons).
2. Argillic horizon - the zone from 36 to 108 centimeters (Bt1 and Bt2 horizons).
3. Particle-size control section - the zone from 36 to 86 centimeters averages 37 percent clay (Bt1, Bt2 horizons)
ADDITIONAL DATA: NSSL Pedon No. 03N0875, Humboldt County, CA. 6/03
NASIS User Pedon ID: 03CA601151
Keys to Soil Taxonomy, 12th edition
National Cooperative Soil Survey
U.S.A.