LOCATION GIBSONCREEK CA

Established Series
REV.: JWH/JTB/ET
10/2016

GIBSONCREEK SERIES

The Gibsoncreek series consists of very deep, well drained soils formed in colluvium and residuum derived from sandstone and conglomerate. Gibsoncreek soils are on ridges, benches, and sideslopes of mountains. Slopes range from 15 to 75 percent. The mean annual precipitation is about 2160 mm and the mean annual temperature is about 10 degrees C

TAXONOMIC CLASS: Fine-loamy, isotic, isomesic Dystric Haplustepts

TYPICAL PEDON: Gibsoncreek fine sandy loam on a southwest facing 37 percent slope under Douglas-fir, tanoak, Pacific madrone, and California huckleberry, at an elevation of 425 meters. (Colors are for dry soil unless otherwise noted.) When described on May 6, 2004, the soil was moist to 200 cm.

Oi--0 to 4 centimeters; 75 percent very dark brown (7.5YR 2.5/2) and 25 percent pinkish gray (7.5YR 6/2) slightly decomposed plant material, black (7.5YR 2.5/1) rubbed; about 75 percent fiber, 45 percent rubbed; moderately acid (pH 6.0); abrupt wavy boundary. (0 to 5 centimeters thick)

A--4 to 18 centimeters; dark brown (7.5YR 3/2) fine sandy loam, very dark brown (7.5YR 2.5/2) moist; moderate medium granular structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots throughout; 3 percent subangular gravel; strongly acid (pH 5.5); abrupt smooth boundary. (5 to 40 centimeters thick)

Bt1--18 to 52 centimeters; brown (7.5YR 5/3) fine sandy loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure parting to moderate medium granular; moderately hard, friable, nonsticky and slightly plastic; common very fine, fine, and medium roots throughout; common very fine tubular pores; common faint clay films on all faces of peds; 3 percent subangular gravel; strongly acid (pH 5.4); clear smooth boundary.

Bt2--52 to 70 centimeters; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common fine, medium, and coarse roots throughout; few very fine tubular pores; common distinct clay films on all faces of peds; 5 percent subangular strongly cemented sandstone gravel; moderately acid (pH 5.6); clear wavy boundary.

Bt3--70 to 110 centimeters; light yellowish brown (10YR 6/4) gravelly loam, strong brown (7.5YR4/6) moist; weak medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common fine, medium, and coarse roots throughout; few very fine tubular pores; common distinct clay films on all faces of peds and on surfaces along pores; 40 percent subangular strongly cemented sandstone gravel; moderately acid (pH 5.6); clear wavy boundary.

Bt4--110 to 125 centimeters; light yellowish brown (10YR 6/4) very gravelly fine sandy loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure parting to weak medium granular; moderately hard, friable, slightly sticky and slightly plastic; common distinct clay films on all faces of peds; 75 percent subangular strongly cemented sandstone gravel; moderately acid (pH 5.7); clear wavy boundary. (Combined thickness of the Bt horizons is 50 to 110 centimeters)

CBt--125 to 155 centimeters; yellow (10YR 7/6) very paragravelly loam, yellowish brown (10YR 5/4); massive; slightly hard, very friable, nonsticky and nonplastic; few faint clay films around rock fragments; 85 percent subangular moderately cemented sandstone paragravel from shattered bedrock; strongly acid (pH 5.5).

C--155 to 200 centimeters; strongly cemented sandstone bedrock with fine sandy loam-filled fractures, less than 10 cm apart; light yellowish brown (2.5Y 6/4) extremely paragravelly fine sandy loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; 85 percent moderately cemented sandstone paragravel; moderately acid (pH 5.6). (50 to 145 centimeters thick)

TYPE LOCATION: Humboldt County, California; about 3 kilometers southwest of the town of Briceland; USGS Briceland Quadrangle, CA; WGS84 Decimal degrees 40.085671 latitude and -123.9452152 longitude; UTM zone 10 419417mE, 4437694mN; NAD 83.

RANGE IN CHARACTERISTICS:

Soil Temperature: The mean annual soil temperature at 50 centimeters is 9 to 11 degrees C (48 to 51 degrees F) and the difference between mean summer and mean winter soil temperatures is less than 6 degrees C. The soil has an isomesic soil temperature regime.

Soil Moisture: The soil moisture control section is dry in some or all parts for 90 or more cumulative days in normal years and it is moist in some part for more than 180 cumulative days or for 90 or more consecutive days per year. The soil has an ustic soil moisture regime.

Surface Fragments: 0 to 14 percent rounded indurated gravel from conglomerate and 0 to 14 percent subangular strongly cemented sandstone gravel

Base Saturation: less than 60 percent by ammonium acetate in some horizons between 25 and 75 centimeters from the mineral soil surface

Particle size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 0 to 35 percent subangular strongly cemented sandstone or rounded indurated from conglomerate
Pararock fragments: 0 to 15 percent subangular weakly to moderately cemented sandstone
Reaction: strongly or moderately acid

A horizon:
Hue: 7.5YR or 10YR
Value: 3 to 6, 2 to 4 moist
Chroma: 2 to 4, dry or moist
Texture: loam or fine sandy loam
Clay content: 15 to 24 percent
Rock fragments: 0 to 5 percent
Pararock fragments: 0 to 5 percent
Reaction: strongly or moderately acid

Bt horizons:
Hue: 7.5YR or 10YR
Value: 5 to 8, 4 or 5 moist
Chroma: 3 to 6, dry or moist
Texture of fine earth: loam, sandy clay loam, silty clay loam, or clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 34 percent
Pararock fragments: 3 to 59 percent
Reaction: strongly or moderately acid

C horizons:
Hue: 10YR or 2.5Y
Value: 5 to 8, 4 or 5 moist
Chroma: 3 to 6 (dry or moist)
Texture of fine earth: loam, sandy loam, or sandy clay loam
Clay content: 15 to 30 percent
Rock fragments: 0 to 50 percent
Pararock fragments: 35 to 89 percent
Reaction: strongly or moderately acid

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Gibsoncreek soils are on linear to convex positions on summits, shoulders, and backslopes on ridges, mountain slopes and benches. Slopes are 15 to 75 percent. Elevations range from 300 to 500 meters. These soils formed in residuum and colluvium derived from sandstone and conglomerate. The climate is subhumid with warm, dry summers with a marine layer influence and cool, wet winters. Mean annual precipitation is 1525 to 3050 millimeters and the mean annual temperature is 10 to 15 degrees C. The frost-free period is about 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Telegraph (CA), Sproulish (CA) and Redwohly (CA) soils. Telegraph soils have a base saturation of less than 35 percent by sum of cations and are on linear to slightly concave or convex positions. Sproulish soils have a base saturation by ammonium acetate of less than 60 percent on linear to slightly concave or convex positions. Redwohly soils have bedrock with cracks closer than 10 centimeters apart between 50 and 100 centimeters and are on convex positions.

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

USE AND VEGETATION: This soil is used mainly for timber production, wildlife habitat, and watershed. Natural vegetation is tanoak, Douglas-fir, Pacific madrone, and California huckleberry. Coast redwood can occur in concave areas and lower reaches of drainages and, where present, is less than 50 percent canopy cover.

DISTRIBUTION AND EXTENT: Coastal Redwood Belt; MLRA 4B. The series is not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt County, South Part, California, 2010. The name is from Gibson Creek.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon-the zone from 0 to 18 centimeters (Oi and A horizons).
2. Cambic horizon-the zone from 18 to 155 centimeters (Bt1, Bt2, Bt3, Bt4 and CBt horizons).
3. Particle-size control section: the zone from 29 to 104 centimeters averages 25 percent clay, by weight, and 18% gravel by volume (Bt1, Bt2 and Bt3 horizons). Particle size Family was determined from recalculated textures due to isotic mineralogy.
4. Isotic feature: 15 bar water/clay is 0.69 or more and the NaF pH is greater than 9.1 in all horizons. Clay content for particle size family determination was calculated due to poor dispersion.
5. Dystric subgroup: base saturation between 25 and 75 centimeters below the mineral soil surface is 20 to 41, by sum of cations.

ADDITIONAL DATA: NSSL Pedon No. 05N0138.
NASIS User Pedon ID 04CA601284

Keys to Soil Taxonomy, 12th edition.

National Cooperative Soil Survey
U.S.A.