LOCATION BURGSBLOCK CA

Established Series
REV: JWH/JME/ET
07/2016

BURGSBLOCK SERIES

The Burgsblock series consists of very deep, well drained soils that formed in colluvium and residuum derived from sandstone and mudstone. Burgsblock soils are on mountains and have slopes of 15 to 75 percent. The mean annual precipitation is about 2160 mm and the mean annual temperature is about 13 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Typic Palexerults

TYPICAL PEDON: Burgsblock very gravelly silt loam on a north-facing linear convex slope of 40 percent under Douglas-fir, tanoak, and California huckleberry at 621 meters elevation. (Colors are for dry soil unless otherwise stated). When described on September 17, 2008, the soil was dry to 120 centimeters.

Oi--0 to 2 centimeters, dark grayish brown (10YR 4/2) slightly decomposed plant material, very dark brown (7.5YR 2.5/2) rubbed moist; about 100 percent fiber; 80 percent rubbed; nonsticky and nonplastic; 34 percent gravel; moderately acid (pH 6.0); abrupt smooth boundary. (0 to 5 centimeters thick)

A--2 to 20 centimeters; brown (7.5YR 5/4) very gravelly silt loam, dark brown (7.5YR 3/3) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine, medium, and very fine roots throughout; common very fine tubular pores; 43 percent gravel; strongly acid (pH 5.1); clear smooth boundary. (7 to 35 centimeters thick)

AB--20 to 55 centimeters; light brown (7.5YR 6/4) very gravelly silt loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; common very fine, fine, medium, coarse, and very coarse roots throughout; common very fine tubular pores; 31 percent gravel and 15 percent cobbles; strongly acid (pH 5.3); clear wavy boundary. (0 to 35 centimeters thick)

Bt1--55 to 120 centimeters; light brown (7.5YR 6/4) very gravelly clay loam, strong brown (7.5YR 4/6) moist; strong medium subangular blocky structure, hard, friable, moderately sticky and very plastic; common very fine, fine, and medium roots and few coarse roots throughout; common very fine tubular pores; 10 percent distinct clay films on top surfaces of rock fragments and 30 percent prominent clay films on all faces of peds; 48 percent gravel; strongly acid (pH 5.3); gradual wavy boundary. (12 to 65 centimeters thick)

Bt2--120 to 170 centimeters; light yellowish brown (10YR 6/4) extremely gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure, hard, friable, slightly sticky and moderately plastic; common very fine, medium, and coarse roots throughout; common very fine and fine tubular pores; 10 percent distinct clay films on top surfaces of rock fragments and 30 percent prominent clay films on all faces of peds; 56 percent gravel and 5 percent cobbles; strongly acid (pH 5.5); gradual wavy boundary. (20 to 95 centimeters thick)

Bt3--170 to 200 centimeters; light yellowish brown (10YR 6/4) very gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; hard, friable, slightly sticky and moderately plastic; common very fine and fine roots throughout; common very fine and fine irregular pores; 10 percent distinct clay films on rock fragments and 30 percent prominent clay films on all faces of peds; 46 percent gravel; strongly acid (pH 5.5). (25 to 120 centimeters thick)

TYPE LOCATION: Humboldt County, California; located approximately 7 miles northwest of Blocksburg, CA; USGS Blocksburg Quadrangle, California; WGS84 Decimal degrees 40.3586111 latitude and -123.7480556 longitude; UTM Zone 10 436486mE 4467833mN; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is dry in all parts for 45 or more consecutive days after the summer solstice and moist in all parts from November through May. The soils have a xeric moisture regime.

Soil temperature: The mean annual soil temperature at 50 centimeters is 10 to 14 degrees C.

Particle size control section (weighted average):
Clay content: 23 to 35 percent
Rock fragment content: 35 to 65 percent with 35 to 90 percent gravel, 0 to 35 percent cobbles, and 0 to 15 percent stones.

A horizon:
Hue: 10YR or 7.5YR
Value: 3 to 6, 2 or 3 moist
Chroma: 1 to 4, dry or moist
Texture of the fine earth: loam or silt loam
Clay content: 17 to 26
Rock fragments: 15 to 50 percent
Reaction: strongly to slightly acid

Upper Bt horizons:
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5 or 6, 4 or 5 moist
Chroma: 3 to 6, dry or moist
Texture of the fine earth: loam, sandy clay loam, or clay loam
Clay content: 22 to 34 percent
Rock fragments: 35 to 60 percent gravel, 0 to 15 percent cobbles, 0 to 5 percent stones
Reaction: slightly to strongly acid

Lower Bt horizons:
Hue: 10YR or 2.5Y
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture of the fine earth: loam, sandy clay loam, or clay loam
Clay content: 22 to 34 percent
Rock fragments: 35 to 90 percent gravel, 0 to 15 percent cobbles, 0 to 5 percent stones
Reaction: slightly to strongly acid

C horizon when present:
Hue: 10YR or 2.5Y
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture of the fine earth: loam, sandy clay loam, or clay loam
Clay content: 22 to 39 percent
Rock fragments: 35 to 90 percent
Reaction: slightly to strongly acid

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Burgsblock soils are on linear to convex positions on summits, shoulders, and backslopes on mountain slopes and ridges. Slopes are 15 to 75 percent. Elevations are 60 to 1000 meters. These soils formed in colluvium and residuum derived from sandstone and mudstone. The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is 1250 to 3050 millimeters. The mean annual temperature is 12 to 14 degrees C. Mean January temperature is about 7 degrees C, mean July temperature is about 22 degrees C, and the mean annual temperature is 12 to 14 degrees C. Frost free season is about 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coolyork, Rockyglen, and Tannin soils. Coolyork soils have a mollic epipedon. Rockyglen soils lack an argillic horizon. Tannin soils contain less than 35 percent rock fragments in the particle size control section. Coolyork soils occur on concave positions on backslopes. Rockyglen soils occur on convex to linear positions. Tannin soils occur on linear to concave positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used mainly for timber production, wildlife habitat, and for limited grazing. Natural vegetation is Douglas-fir, tanoak, Pacific madrone, big leaf maple, California laurel, black oak, and Oregon white oak.

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 Soil Survey, Southern Part, California. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon: The zone from 0 to 55 centimeters. (Oi A, and AB horizons)
2. Argillic horizon: The zone from 55 to 200 centimeters. (Bt1, Bt2, and Bt3, horizons)
3. Particle size control section: The zone from 55 to 105 centimeters averages 33 percent clay by weight, and 48 percent gravel by volume. (Bt1 horizon)
4. Palehumults feature: the clay percentage does not drop 6.6 percent percent from 33 percent.

ADDITIONAL DATA: NSSL Pedon 09N0112, Humboldt County, CA.
NASIS User Pedon ID 08CA6011065

Keys to Soil Taxonomy, 12th edition.

National Cooperative Soil Survey
U.S.A.