LOCATION HAWTHORSE CA
Established Series
REV: BAL/ACF/ET
10/2016
HAWTHORSE SERIES
The Hawthorse series consists of very deep, somewhat poorly drained soils formed in colluvium and residuum derived from sandstone and mudstone. These soils are on mountains and have slopes of 9 to 50 percent. Mean annual precipitation is 1524 millimeters (59 inches) and the mean annual temperature is 12 degrees C (54 degrees F).
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Oxyaquic Palehumults
TYPICAL PEDON: Hawthorse gravely loam - under a stand of annual and perennial grasses at 945 meters (3099 feet) elevation. When described on September 7, 2004, the soil was dry throughout. (Colors are for dry soil unless otherwise stated).
A1--0 to 8 centimeters (0 to 3 inches); gravelly loam, brown (10YR 5/3) very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky parting to strong very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine tubular pores; 20 percent gravel; strongly acid (pH 5.2); clear smooth boundary.
A2--8 to 35 centimeters (3 to 14 inches); brown (10YR 5/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; strong fine subangular blocky parting to moderate very fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; many very fine through medium tubular pores; 20 percent gravel; strongly acid (pH 5.2); clear smooth boundary. (Combined thickness of A horizons is 10 to 40 centimeters)
Bt--35 to 65 centimeters (14 to 26 inches); brown (10YR 5/3) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; strong fine and medium subangular blocky structure; hard, firm, very sticky and very plastic; many very fine roots; many fine and medium tubular pores; 15 percent fine very weakly cemented strong brown (7.5YR 5/6) iron-manganese masses; common distinct clay films on all faces of peds; 20 percent gravel; strongly acid (pH 5.2); clear smooth boundary. (25 to 100 centimeters thick)
Btg1--65 to 99 centimeters (26 to 39 inches); light brownish gray (2.5Y 6/2) very gravelly silty clay, grayish brown (2.5Y 5/2) moist; strong fine and medium subangular blocky structure; hard, firm, very sticky and very plastic; many fine roots; common fine tubular pores; common distinct clay films on all faces of peds; 20 percent fine very weakly cemented strong brown (7.5YR 5/6) iron-manganese masses; 30 percent gravel, 10 percent cobbles; very strongly acid (pH 5.0); clear smooth boundary.
Btg2--99 to 129 centimeters (39 to 51 inches); light gray (5Y 7/2) very paragravelly silty clay, light brownish gray (2.5Y 6/2) moist; strong very fine subangular blocky structure; hard, firm, very sticky and very plastic; common fine roots; common fine tubular pores; common distinct clay films on all faces of peds; 20 percent fine very weakly cemented strong brown (7.5YR 5/6) iron-manganese masses; 30 percent weakly cemented paragravel, 5 percent gravel; very strongly acid (pH 5.0); gradual smooth boundary.
Btg3--129 to 163 centimeters (51 to 64 inches); light olive gray (5Y 6/2) very paragravelly silty clay, gray (5Y 5/1) moist; strong very fine subangular blocky structure; hard, firm, very sticky and very plastic; moderately few fine roots; common fine tubular pores; few distinct clay films on all faces of peds; 20 percent fine very weakly cemented strong brown (7.5YR 5/6) iron-manganese masses; 30 percent weakly cemented paragravel, 5 percent gravel; very strongly acid (pH 5.0). (Combined thickness of Btg horizons is 50 to 125 centimeters)
TYPE LOCATION: Humboldt County, California; USGS Quadrangle Maple Creek; WGS84 Decimal degrees 40.813627 latitude and -123.8278908 longitude; UTM Zone 10 430177mE, 4518398mN, NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is dry from July 1st to October 15th and moist in all parts from November 15 to June 1st. This soil has a xeric soil moisture regime.
Soil temperature: The mean annual soil temperature is 10 to 15 degrees C (50 to 59 degrees F). The difference between mean summer and mean winter temperature is 6 to 10 degrees C. The soils have a mesic soil temperature regime.
Soil reaction: very strongly acid to moderately acid throughout the soil profile.
Base saturation (by sum of cations) is less than 35 percent at 125 centimeters below the top of the argillic horizon.
Organic carbon is 12kg or more in the upper cubic meter of the mineral soil or the upper 15 cm of the argillic has 0.9 percent or more organic carbon.
Depth to redoximorphic features: 25 to 50 centimeters (10 to 20 inches).
Particle Size Control Section (weighted average):
Clay content: averages 35 to 45 percent
Rock fragments: 0 to 30 percent gravel and 0 to 5 percent cobbles.
A horizons
Hue: 10YR or 2.5Y
Value: 3 through 5 dry; 2 or 3 moist
Chroma: 3 or 4 dry; 2 or 3 moist
Texture of the fine earth fraction: loam
Clay content: 12 to 25 percent
Rock fragments: 0 to 30 percent gravel
Bt horizons
Hue: 10YR or 2.5Y
Value: 4 through 7 dry; 3 through 5 moist
Chroma: 2 through 4 dry or moist
Texture of the fine earth fraction: silty clay loam, clay loam, silty clay
Clay content: 30 to 45 percent
Rock fragments: 0 to 30 percent gravel
Redoximorphic features: fine and medium, weakly cemented, iron-manganese masses in the matrix.
Quantity: none to many
Hue: 7.5YR, 10YR, 2.5Y
Value: 3 through 5 moist
Chroma: 3 through 6 moist
Btg horizons
Hue: 10YR, 2.5Y or 5Y
Value: 4 through 7, dry or moist
Chroma: 1 or 2 dry or moist
Texture of the fine earth fraction: silty clay loam, clay loam, silty clay
Clay content: 35 to 45 percent
Rock fragments: 0 to 30 percent gravel and 0 to 10 percent cobble
Parafragments: 30 to 60 percent
Redoximorphic features: fine, medium, and coarse, weakly cemented, iron-manganese masses in the matrix.
Quantity: few to many
Hue: 7.5YR, 10YR, 2.5Y
Value: 3 through 5 moist
Chroma: 3 through 6 moist
Some pedons have C horizons
C horizons
Hue: 10YR, 2.5Y or 5Y
Value: 4 through 7, dry or moist
Chroma: 1 or 2 dry or moist
Texture of the fine earth fraction: silty clay
Clay content: 40 to 45 percent
Parafragments: 35 to 90 percent
Redoximorphic features: fine, medium, and coarse, weakly cemented, iron-manganese masses in the matrix.
Quantity: few to many
Hue: 7.5YR, 10YR, 2.5Y
Value: 3 through 5 moist
Chroma: 3 through 6 moist
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: These soils occur on mountain slopes with slopes of 9 to 50 percent. They are in concave slope positions at elevations of 322 to 1206 meters (1056 to 3957 feet). These soils formed in colluvium and residuum derived from sandstone and mudstone. The climate is subhumid with warm dry summers and cool, wet winters. The mean annual precipitation is 1250 to 2032 millimeters (49 to 80 inches). Mean January temperature is about 7 degrees C; mean July temperature is about 15 degrees C; and the mean annual temperature is 10 to 15 degrees C (50 to 59 degrees F). The frost free period is about 240 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Flyat and
Rockus series. Flyat soils are fine-loamy with less than 35 percent clay in the particle size control section. Rockus soils are loamy-skeletal with greater than 35 percent rock fragments in the particle size control section. The Flyat soils are found on linear and convex slope positions generally above the Hawthorse soils. The Rockus soils are found in strongly convex slope positions generally above the Hawthorse soils.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained; medium to very high runoff; low saturated hydraulic conductivity. A water table is between 25 and 75 centimeters (10 and 30 inches) in January, February, and March.
USE AND VEGETATION: This soil is mostly used for livestock grazing, wildlife habitat, and watershed protection. Natural vegetation is Bristly dogtail grass, blue wildrye, soft brome, and orchardgrass. Douglas-fir invades readily in the absence of fire.
DISTRIBUTION AND EXTENT: Siskyou-Trinity Area, MLRA 5. The name is coined. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Humboldt County, California, 2012. Proposed 2005. The name is coined.
REMARKS: Diagnostic horizons and features include:
1. Umbric horizon - the zone from 0 to 65 centimeters (A1, A2, & Bt horizon)
2. Argillic horizon - the zone from 35 to 163 centimeters (Bt, Btg1, Btg2, & Btg3, horizons)
3. Aquic conditions - the zone from 35 to 163 centimeters (Bt, Btg1, Btg2, & Btg3 horizons)
4. Particle size control section - the zone from 35 to 85 centimeters, averaging (by weight) 36 percent clay and 28 percent rock fragments.
ADDITIONAL DATA:
NSSL Pedon Number: 05N0647
NASIS User Pedon ID: 04CA023605074
Soil classified using Keys to Soil Taxonomy, 12th edition.
National Cooperative Soil Survey
U.S.A.