LOCATION SURPUR                  CA

Established Series
Rev: JPS/ET
10/2016

SURPUR SERIES

The Surpur series consists of very deep, well drained soils formed in colluvium and residuum from weakly consolidated tectonically uplifted fluvial, beach, and dune deposits derived from mixed sources. Surpur soils are on mountains and have slopes of 2 to 50 percent. The mean annual precipitation is about 2030 millimeters (80 inches) and the mean annual temperature is about 11 degrees C (52 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, isomesic Andic Haplohumults

TYPICAL PEDON: Surpur gravelly loam - on an east-facing slightly convex slope of 10 percent under redwood, Douglas fir, tanoak, California huckleberry, Pacific rhododendron, and salal at 540 meters (1770 feet) elevation. (Colors are for moist soil unless otherwise stated. When described April 22, 2003, the soil was moist throughout.)

Oi--0 to 10 centimeters (0 to 4 inches); dark brown (10YR 3/3) fresh and slightly decomposed conifer needles, tanoak leaves, and twigs, yellowish brown (10YR 5/4) dry; many very fine and fine and few medium roots; many very fine and fine interstitial pores; very strongly acid (pH 5.0); abrupt smooth boundary. (0 to 10 centimeters thick)

A--10 to 31 centimeters (4 to 12 inches); dark brown (10YR 3/3) gravelly loam, yellowish brown (10YR 5/4) dry; weak medium granular and very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine and fine tubular pores; 20 percent well rounded gravel; slightly acid (pH 6.2); abrupt wavy boundary. (5 to 30 centimeters thick)

Bt1--31 to 47 centimeters (12 to 19 inches); strong brown (7.5YR 4/6) gravelly clay loam, strong brown (7.5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine, and few medium roots; common very fine and fine irregular and common very fine and fine tubular pores; few faint clay films on faces of peds; 20 percent well rounded gravel; slightly acid (pH 6.2); clear smooth boundary.

Bt2--47 to 72 centimeters (19 to 28 inches); strong brown (7.5YR 4/6) clay loam, strong brown (7.5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine and medium; and few coarse roots; common very fine and fine, and few medium tubular pores; few faint clay films on faces of peds; 10 percent well rounded gravel; moderately acid (pH 5.6); gradual wavy boundary.

Bt3--72 to 103 centimeters (28 to 41 inches); strong brown (7.5YR 5/6) clay loam, reddish yellow (7.5YR 6/8) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine and medium, and few coarse roots; common very fine and fine, and few medium tubular pores; few faint clay films on surfaces of peds and on rock fragments; 10 percent well rounded gravel; moderately acid (pH 5.6); clear smooth boundary.

Bt4--103 to 130 centimeters (41 to 51 inches); strong brown (7.5YR 5/6) fine sandy loam, reddish yellow (7.5YR 6/8) dry; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine and fine and few medium tubular pores; common distinct clay films between sand grains and few faint on faces of peds; 10 percent well rounded gravel; moderately acid (pH 5.6); gradual wavy boundary. (Combined thickness of Bt horizons is 30 to 125 centimeters)

BCt--130 to 159 centimeters (51 to 63 inches); strong brown (7.5YR 5/6) fine sandy loam, reddish yellow (7.5YR 6/8) dry; weak medium and coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine, and common medium roots; common very fine and fine tubular pores; few distinct clay films bridging sand grains; 2 percent well rounded gravel; few fine bands of lamellae, 5 to 15 mm thick reddish brown (2.5YR 4/4) moist; strongly acid (pH 5.4); clear wavy boundary. (0 to 70 centimeters thick)

C--159 to 200 centimeters (63 to 79 inches); yellowish brown (10YR 5/8) loamy sand, brownish yellow (10YR 6/8) dry; single grained ; loose, nonsticky and nonplastic; few very fine and fine, and common medium and coarse roots; common very fine and fine interstitial pores; 2 percent well rounded gravel; few fine bands of lamellae 1 to 4 mm thick yellowish red (5YR 5/8) moist; strongly acid (pH 5.4). (0 to 100 centimeters thick)

TYPE LOCATION: Redwood National Park, Humboldt County, California; Holter Ridge, located 10 kilometers north on Lost Man Creek Trail from Ball Hills Road trailhead; southeast quarter, northwest quarter, Section 28, T. 11N. R. 2E., WGS84 Decimal 41.1440833 latitude and -124.1072500 longitude; HBLM; USGS Holter Ridge Quadrangle. UTM Zone 10 420205mE 4573981mN; NAD83

RANGE IN CHARACTERISTICS:

Soil Moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes nearly dry in the upper part from about September 15 to October 15 in most years. The soils have an Udic moisture regime.

Soil Temperature: The mean annual soil temperature is 10 to 13 degrees C (50 to 55 degrees F). The difference between mean summer and mean winter temperature is 3 to 5 degrees C.

Base saturation (by sum of bases) is less than 35 percent at 156 cm.

Organic Matter: There is 12 to 25 kg per square meter of organic carbon to a depth of one meter.

Clay content decreases by more than 20 percent within 150 cm of the mineral soil surface.

CEC to clay ratio is 16 to 24 meq/100g in the major part of the argillic horizon.

Reaction is moderately or strongly acid throughout. Base saturation is 5 to 35 percent between depths of 25 to 200 centimeters.

Particle-Size Control Section (weighted average):
Rock fragments: 0 to 15 percent gravel.
Clay content: 27 to 32 percent clay.

O horizon

Hue: 10YR.
Value: 2 through 6 dry and moist.
Chroma: 1 through 4 dry and moist.

Texture: slightly decomposed organic material.
Wood fragments: 0 to 35 percent.
Reaction: moderately to very strongly acid.

A horizon

Hue: 7.5YR, or 10YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 3 through 6 dry and moist.

Texture of fine earth: loam.
Rock fragments: 0 to 25 percent gravel.
Clay content: 12 to 25 percent.

Bt horizon

Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3 through 6 moist.
Chroma: 4 through 8 dry, 4 through 8 moist.

Texture of fine earth: fine sandy loam, loam, clay loam, or silty clay loam.
Rock fragments: 0 to 30 percent gravel.
Clay content: 15 to 35 percent.

C horizon

Hue: 7.5YR or 10YR
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 4 through 8 dry, 4 through 8 moist.

Texture of fine earth: loamy sand, fine sandy loam.
Rock fragments: 0 to 20 percent gravel and 0 to 25 percent paragravel.
Clay content: 0 to 18 percent.

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: Surpur soils occur on ridges and upper, mountain slopes. Slopes are 2 to 50 percent. Elevations are 233 to 690 meters (760 to 2260 feet). The soils formed in colluvium and residuum from weakly consolidated tectonically uplifted fluvial, beach, and dune deposits derived from mixed sources. The climate is humid with cool foggy summers and cool moist winters. Coastal influence limits the annual and diurnal range in temperature. Mean annual precipitation ranges from 1780 to 2550 millimeters (70 to 100 inches). 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 (50 to 55 degrees F). Frost-free season is 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mettah and the Ossagon soils. Mettah soils have greater than 35 percent clay in the particle-size control section. Ossagon soils have an umbric epipedon. The Mettah soils are found on silty marine and non-marine sediments. The Ossagon soils are found at lower elevations and closer to the coast.

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

USE AND VEGETATION: This soil has been used for commercial timber and is used for recreation, wildlife and watershed. Natural vegetation consists of redwood, Douglas fir, western hemlock, tanoak, California huckleberry, Pacific rhododendron, salal, and western swordfern.

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

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

SERIES ESTABLISHED: Humboldt Del Norte area, California 2007. Source of name is from Surpur Creek east of the town of Orick.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Ochric epipedon - the zone from 0 to 31 centimeters (Oi and A horizon).
2. Argillic horizon - the zone from 31 to 159 centimeters (Bt1, Bt2, Bt3 and Bt4 horizons).
3. Ultisol feature - base saturation of 4 percent at the critical depth, 125 centimeters below the upper boundary of the argillic horizon
4. Haplohumult features - Clay does not remain at least 80 percent of its maximum to a depth of 200 centimeters
5. Andic subgroup properties - The zone from 10 to 31 centimeters (greater than 18cm thick) has a bulk density of 0.93 g/cm3 and Al plus Fe of 1.13 percent. (A horizon)
6. Lamellae - within the zone from 130 to 200 centimeters. (BCt and C horizons)
7. Particle-size control section - the zone from 31 to 81 centimeters, averages 28 percent clay, 24 percent fine sand and coarser, by weight, and 13 percent rock fragments by volume.(Bt1 horizon)

ADDITIONAL DATA:

NSSL, Lincoln Lab sample number: 05N0018

Nasis User Pedon ID: 03CA605REDW037

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

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National Cooperative Soil Survey
U.S.A.