LOCATION SCOTIABLUFFS CA

Established Series
Rev: SAA/ET
05/2016

SCOTIABLUFFS SERIES

The Scotiabluffs series consists of moderately deep, well drained soils formed in residuum from sandstone with minor amounts of siltstone and gravelly conglomerate. Scotiabluffs soils are on mountains. Slopes range from 15 to 110 percent. The mean annual precipitation is about 1525 milimeters and the mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Coarse-loamy, isotic, isomesic Typic Dystrudepts

TYPICAL PEDON: Scotiabluffs fine sandy loam on a northeast facing slope of 46 percent under a logged forest canopy of coast redwood, Douglas-fir, oceanspray, California huckleberry, thimbleberry, salal, northern maidenhair, and western swordfern. (Colors are for moist soil unless otherwise stated) When described on October 1, 2004, the soil was slightly moist throughout.

Oi--0 to 6 centimeters; slightly decomposed plant material; very strongly acid (pH 4.8); clear smooth boundary. (O horizon is 0 to 16 centimeters thick)

A--6 to 29 centimeters; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; moderate very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, medium, and coarse roots throughout; common very fine irregular and common fine tubular pores; strongly acid (pH 5.4); clear smooth boundary. (A horizon is 10 to 24 centimeters thick)

Bw1--29 to 60 centimeters; very dark grayish brown (10YR 3/2) fine sandy loam, light brownish gray (10YR 6/2) dry; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine and medium roots throughout; common fine tubular and very fine irregular pores; strongly acid (pH 5.5); gradual smooth boundary.

Bw2--60 to 81 centimeters; dark brown (7.5YR 3/3) fine sandy loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine, medium, and coarse roots throughout; common very fine irregular and fine tubular pores; strongly acid (pH 5.3); abrupt wavy boundary. (Combined thickness of the Bw horizons is 25 to 90 centimeters)

Cr1--81 to 98 centimeters; 85 percent olive brown (2.5Y 4/3) and 15 percent dark yellowish brown (10YR 4/4) very weakly cemented sandstone bedrock with cracks spaced 10 to 20 centimeters apart, [ssaa1]85 percent light brownish gray (2.5Y 6/2) and 15 percent yellowish brown (10YR 5/4) dry; common very fine and medium roots in mat on top of horizon and in cracks; moderately acid (pH 5.6); abrupt wavy boundary.

Cr2--98 to 200 centimeters; 85 percent light brownish gray (2.5Y 6/2) and 15 percent yellowish brown (10YR 5/4) very weakly cemented sandstone bedrock with cracks spaced 10 to 20 centimeters apart; 85 percent gray (2.5Y 6/1) and 15 percent dark yellowish brown (10YR 4/4) dry; many very fine and common fine roots in mat on top of horizon and in cracks; slightly acid (pH 6.2). (Combined thickness of the Cr horizons is 50 to 150 centimeters)

TYPE LOCATION: Humboldt County, California; About 1.2 kilometers north of the town of Rio Dell; USGS Hydesville quadrangle; WGS84 Decimal degrees 40.5177778 latitude and -124.1041667 longitude; UTM Zone 10 406474mE, 4485821mN; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is not dry in any part for as long as 90 cumulative days in normal years. The soils have a udic moisture regime.

Soil Temperature: The mean annual soil temperature at 50 centimeters is 10 to 13 degrees C. The difference between mean summer and mean winter temperature is less than 6 degrees C. The soils have an isomesic soil temperature regime.

Depth to Paralithic Contact: 50 to 100 centimeters

Base Saturation: Less than 60 percent by Ammonium Acetate in one or more horizons between 25 centimeters and the paralithic contact.

Particle size control section (weighted average):
Clay content: 10 to 17 percent
Rock fragments (by volume): 0 to 14 percent indurated rounded gravel from conglomerate of mixed mineralogy.
Pararock fragments (by volume): 0 to 14 percent very weakly cemented sandstone paragravel
Reaction: strongly to slightly acid

A horizon:
Hue: 10YR or 2.5Y
Value: 2 through 4, 4 through 6 dry
Chroma: 1 through 3, moist or dry
Texture of fine earth: loam and fine sandy loam
Rock fragments: 0 to 5 percent gravel
Pararock fragments: 0 to 14 percent paragravel
Clay content: 8 to 19 percent

Bw horizon:
Hue: 7.5YR, 10YR, 2.5Y
Value: 4 through 6 moist, 5 through 7 dry
Chroma: 2 through 4, moist or dry
Texture of fine earth: loam, fine sandy loam, and sandy loam
Rock fragments: 0 to 14 percent gravel
Pararock fragments: 0 to 59 percent paragravel, 0 to 5 percent paracobbles
Clay content: 8 to 19 percent

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Scotiabluffs soils are on convex summit, backslope, and shoulder positions on ridges and mountain slopes. Slopes are 15 to 110 percent. Elevations are 30 to 640 meters. These soils formed in residuum from sandstone with minor amounts of siltstone and gravelly conglomerate. The climate is humid with cool, foggy summers and cool, wet winters. Mean annual precipitation is 1140 to 2160 millimeters. Mean January temperature is about 9 degrees C, mean July temperature is about 14 degrees C, and the mean annual temperature is 10 to 13 degrees C. Frost free season is about 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fiedler (CA), , Nanningcreek (CA), Oeschger (CA), and Petellen (CA), , soils. Fiedler soils have between 18 and 30 percent clay in the particle size control section. Nanningcreek soils have redoximorphic features between 50 and 100 centimeters of the mineral soil surface, and have 18 to 34 percent clay in the particle size control section. Oeschger soils are very deep. Petellen soils have greater than 35 percent rock fragments in the particle size control section. Fielder soils occur on linear to slightly concave or convex positions. Nanningcreek soils are on linear to concave positions and in drainageways. Oeschger soils are on linear to slightly concave or convex positions. Petellen soils occur on linear to convex positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, medium to high runoff, moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used for timber production, wildlife habitat, watershed, and recreation. Natural vegetation includes redwood, Douglas-fir, Sitka spruce, grand fir, tanoak, red alder, Pacific madrone, California hazel, California huckleberry, salal, thimbleberry, red huckleberry, and western swordfern.

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 Soil Survey, South Part, California, 2011. The name is from Scotia Bluffs.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from 0 to 29 centimeters (Oi and A horizon).
2. Cambic horizon - the zone from 29 to 81 centimeters (Bw1 and Bw2 horizon).
3. Paralithic contact - the zone from 81 to 200 centimeters (Cr horizons).
4. Particle-size control section - the zone from 31 to 81 centimeters averages 14 percent clay and 60 percent fine sand or coarser (Bw1 and Bw2 horizons).
5. Isotic feature: 15 bar water/clay is 0.6 and the NaF pH is between 9.4 and 8.5 in the zone from 6 to 81 centimeters (A, Bw1, and Bw2 horizons), which includes the entire mineralogical control section.

ADDITIONAL DATA: National Soil Survey Laboratory Pedon No. 05NO135; NASIS User Pedon ID 04-CA600-085

Keys to Soil Taxonomy, 12th edition

National Cooperative Soil Survey
U.S.A.