LOCATION LEGGETTCREEK CA
Established Series
IRD: JWH/JTB/ET
10/2016
LEGGETTCREEK SERIES
The Leggettcreek series consists of moderately deep, well drained soils formed in residuum derived from sandstone. Leggettcreek soils are on mountains and ridges. Slopes range from 50 to 75 percent. Mean annual precipitation is about 1650 mm and the mean annual temperature is about 11 degrees C.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, isomesic Dystric Haplustepts
TYPICAL PEDON: Leggettcreek silt loam on a northeast facing 54 percent slope under Douglas-fir, tanoak, and redwood at an elevation of 168 meters. (Colors are for dry soil unless otherwise noted.) When described on 5/7/2008, the soil was moist throughout.
Oi--0 to 5 cm; 10 percent very dark grayish brown (10YR 3/2) and 90 percent pinkish gray (7.5YR 6/2) slightly decomposed plant material, very dark brown (10YR 2/2) and black (10YR 2/1) rubbed moist; about 100 percent fiber; 90 percent rubbed; moderately acid (pH 6.0); abrupt smooth boundary. (0 to 5 cm thick)
A--5 to 12 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, few fine, and many medium roots throughout; common very fine, fine, and medium tubular pores; 5 percent paragravel; strongly acid (pH 5.2); clear wavy boundary. (5 to 25 cm thick)
Bw1--12 to 22 cm; light yellowish brown (10YR 6/4)fine sandy loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, few fine, many medium, common coarse and very coarse roots throughout; common very fine, fine, and medium tubular pores; 5 percent paragravel; strongly acid (pH 5.5); gradual wavy boundary.
Bw2--22 to 47 cm; very pale brown (10YR 7/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium structure, slightly hard, very friable, slightly sticky and slightly plastic; few very fine, many medium, common coarse, and common very coarse roots throughout; common very fine, fine, medium, and coarse tubular pores; 5 percent paragravel; moderately acid (pH 5.6); clear wavy boundary.
Bw3--47 to 88 cm; yellow (10YR 7/6) extremely paragravelly fine sandy loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine, few fine, many medium, common coarse and very coarse roots throughout; common very fine, fine, and medium tubular pores; 60 percent paragravel; moderately acid (pH 5.8); abrupt wavy boundary. (Combined thickness of the Bw horizons is 20 to 95 cm)
Cr--88 to 200 cm; yellow (10YR 7/6) very weakly cemented sandstone with cracks 10 to 20 centimeters apart; few very fine, fine, medium, coarse, and very coarse roots in cracks.
TYPE LOCATION: Humboldt County, California; about 3 kilometers north of the town of Redway; USGS Miranda Quadrangle, CA; WGS84 Decimal degrees 40.1466675 latitude and -123.8263855 longitude; UTM zone 10 429612mE, 4444376mN; 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 soils have 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 moist in some part for more than 180 cumulative days or for 90 or more consecutive days per year. The soils have an ustic soil moisture regime.
Base Saturation: less than 43 percent by sum of cations throughout.
Depth to paralithic contact: 50 to 100 centimeters
Reaction: strongly to moderately acid
Particle-size control section (weighted average):
Clay content: 10 to 17 percent
Rock fragments: 0 to 34 percent
Pararock fragments: 5 to 75 percent
A horizon:
Value: 4 to 6, 2 to 4 moist
Chroma: 2 to 3, dry or moist
Clay content: 10 to 17 percent
Rock fragments: 0 to 14 percent indurated, rounded gravel
Pararock fragments: 0 to 14 percent very weakly cemented paragravel.
Bw horizons:
Hue: 10YR or 2.5Y
Value: 5 to 7, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture of fine earth: loam, fine sandy loam, or sandy loam
Clay content: 10 to 17 percent
Rock fragments: 0 to 34 indurated, rounded gravel
Pararock fragments: 5 to 75 percent weakly cemented paragravel, 0 to 34 percent weakly cemented paracobbles.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Leggettcreek soils are on strongly convex positions on mountain slopes and ridges that experience limited summer fog. Slopes are 50 to 75 percent. Elevations are 60 to 400 meters. These soils formed in residuum derived from Quaternary- and Tertiary- aged sandstone with thin lenses of gravelly conglomerate. The climate is subhumid with warm, dry summers with a marine layer influence and cool, wet winters. Mean annual precipitation is 1250 to 1780 millimeters. The mean annual temperature is 10 to 12 degrees C. The frost free period is 240 to 280 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Gibsoncreek (CA) and
Seelycreek (CA) soils. Seelycreek and Gibsoncreek soils do not have a paralithic contact within 200 centimeters. Gibsoncreek and Seelycreek soils have greater than 18 percent clay in the particle size control section and Seelycreek soils have less than 15 percent fine sand and coarser in the particle size control section. Gibsoncreek soils are on linear to convex positions and Seelycreek soils are on linear to slightly concave or convex positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high runoff; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for timber production, wildlife habitat, and watershed. Natural vegetation includes Douglas-fir, tanoak, Pacific madrone, redwood, and California huckleberry. 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 Leggett Creek.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon: The zone from 0 to 12 centimeters (Oi and A horizons)
2. Cambic horizon: The zone from 12 to 88 centimeters (Bw1, Bw2, and Bw3 horizons)
3. Particle size control section: The zone from 30 to 88 centimeters (Bw1, Bw2, and Bw3 horizons) averages 10 percent clay and 53.3 percent fine sand and coarser, by weight and 44 percent rock fragments, by volume.
4. Paralithic contact: The zone from 88 to 200 centimeters (Cr horizon)
ADDITIONAL DATA: NSSL, Pedon No. 08N0571
Keys to Soil Taxonomy, 12th edition
National Cooperative Soil Survey
U.S.A.