LOCATION SQUASHAN CA
Established Series
Rev: JPS/ET
05/2016
SQUASHAN SERIES
The Squashan series consists of very deep, well drained soils formed in colluvium and residuum from weakly consolidated tectonically uplifted fluvial and beach deposits derived from mixed sources. Squashan soils are on mountains and hills and have slopes of 9 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: Loamy-skeletal, isotic, isomesic Typic Haplohumults
TYPICAL PEDON: Squashan gravelly loam - on a southwest-facing convex slope of 12 percent under redwood, Douglas fir, tanoak, Pacific rhododendron, red huckleberry, salmonberry, salal, swordfern and redwood sorrel at 110 meters (360 feet) elevation. (Colors are for moist soil unless otherwise stated. When described April 28, 2004, the soil was moist throughout.)
Oi--0 to 5 centimeters (0 to 2 inches); very dark brown (10YR 2/2) fresh and slightly decomposed conifer needles, tanoak leaves, and twigs, brown (10YR 5/3); common fine and few medium roots; very strongly acid (pH 4.5). (0 to 5 centimeters thick)
A1--5 to 22 centimeters (2 to 9 inches); very dark grayish brown (10YR 3/2), brown (10YR 4/3) loam dry; moderate medium granular and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and few medium roots; common very fine and fine tubular and interstitial pores; 10 percent well rounded gravel; moderately acid (pH 5.8); clear smooth boundary.
A2--22 to 43 centimeters (9 to 17 inches); dark brown (10YR 3/3) gravelly loam, brown (10YR 5/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and medium, few coarse and very coarse roots; common very fine and fine tubular and interstitial and few medium tubular pores; 20 percent well rounded gravel and 5 percent well rounded cobbles; moderately acid (pH 5.8); clear smooth boundary. (Combined thickness of A horizons is 15 to 40 centimeters)
Bt1--43 to 83 centimeters (17 to 33 inches); brown (7.5YR 4/4) very gravelly clay loam, strong brown (7.5YR 5/6) dry; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine, and very coarse and few medium, and coarse roots; common very fine and fine tubular and interstitial pores; few distinct clay films on faces of peds and rock faces; 45 percent well rounded gravel and 10 percent well rounded cobbles; strongly acid (pH 5.4); clear wavy boundary.
Bt2--83 to 120 centimeters (33 to 47 inches); brown (7.5YR 4/4) very gravelly clay loam, strong brown (7.5YR 5/6) dry; moderate fine subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common very fine and fine, and few medium, coarse and very coarse roots; common very fine and fine tubular and interstitial pores; few distinct clay films on faces of peds and rock faces; 40 percent well rounded gravel and 10 percent well rounded cobbles; strongly acid (pH 5.4); clear wavy boundary.
Bt3--120 to 165 centimeters (47 to 65 inches); strong brown (7.5YR 5/8)extremely gravelly sandy loam, brownish yellow (10YR 6/6) dry; moderate fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; very few fine roots; common very fine and fine tubular and interstitial pores; common distinct clay films on faces of peds and few distinct clay films on rock faces; 55 percent well rounded gravel and 5 percent well rounded cobbles; strongly acid (pH 5.4); clear wavy boundary. (Combined thickness of Bt horizons is 25 to 160 centimeters)
BCt--165 to 200 centimeters (65 to 79 inches); yellowish brown (10YR 5/6) extremely gravelly sandy loam, yellow (10YR 7/6) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine and fine interstitial pores; few distinct clay films on faces of peds and rock faces; 60 percent well rounded gravel and 5 percent well rounded cobbles; 10 percent paragravel; moderately acid (pH 5.6). (0 to 55 centimeters thick)
TYPE LOCATION: Prairie Creek Redwoods State Park, Humboldt County, California; 1.3 miles up Cal Barrel Road; southwest quarter of southeast quarter, Section 36, T. 12N. R. 1E. WGS84 Decimal degrees 41.3760556 latitude and -124.0058333 longitude; HBLM USGS Fern Canyon Quadrangle, UTM Zone 10 415889mE 4580993mN; 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 2 to 4 degrees C.
Organic Matter: There is 12 to 25 kg per square meter of organic carbon to a depth of one meter.
Base saturation: is 9 to 30 percent between the depths of 83 to 200 centimeters.
Surface Fragments: 0 to 30 percent well rounded gravels and 0 to 30 percent well rounded cobbles.
Particle-Size Control Section (weighted average):
Rock fragments: 35 to 70 percent gravel and 0 to 10 percent cobbles.
Clay content: 18 to 30 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: 3 through 5 dry, 3 or 4 moist.
Chroma: 2 or 3 dry, 2 or 3 moist.
Texture of fine earth: loam.
Rock fragments: 10 to 35 percent gravel, 0 to 5 percent cobbles.
Clay content: 15 to 25 percent.
Reaction: moderately or strongly acid
Bt horizon
Hue: 7.5YR or 10YR
Value: 4 through 6 dry, 4 through 7 moist.
Chroma: 4 through 8 dry, 4 through 8 moist.
Texture of fine earth: sandy loam, sandy clay loam, loam, or clay loam.
Rock fragments: 35 to 70 percent gravel and 0 to 10 percent cobbles.
Clay content: 18 to 30 percent.
Reaction: moderately or strongly acid
Some pedons have C horizons.
C horizon
Hue: 10YR or 2.5Y
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 3 through 6 dry, 3 through 6 moist.
Texture of fine earth: sand, loamy sand, or sandy loam.
Rock fragments: 35 to 70 percent gravel, 0 to 10 cobbles, and 0 to 5 percent stones.
Pararock fragments: 0 to 20 percent paragravels
Clay content: 0 to 10 percent.
Reaction: moderately or strongly acid
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Squashan soils occur on ridges and mountain slopes and sideslopes of hills. Slopes are 9 to 50 percent. Elevations are 6 to 593 meters (20 to 1950 feet). The soils formed in colluvium and residuum from older, weakly consolidated tectonically uplifted fluvial and beach 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 1520 to 2290 millimeters (60 to 90 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 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Mettah and the
Ossagon soils. Mettah soils are fine and are redder than 7.5YR throughout. Ossagon soils are fine-loamy. The Mettah soils are found on silty marine and non-marine sediments. The Ossagon soils are found on loamy marine and non-marine sediments.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high 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, Sitka spruce, tanoak, red huckleberry, Pacific rhododendron, and 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 Squashan Creek north of the town of Orick.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon - the zone from 5 to 43 centimeters (A1 and A2 horizons).
2. Argillic horizon - the zone from 43 to 200 centimeters (Bt1, Bt2 and Bt3 horizons).
3. Ultisol feature - base saturation of 30 percent at the critical depth,
180 centimeters below the mineral soil surface
4. Haplohumult features - Clay does not remain at least 80 percent of its maximum to a depth of 200 centimeters
5. Particle-size control section - the zone from 43 to 93 centimeters, averages 29 percent clay, and 67 percent rock fragments.
6. Isotic feature: 15 bar water/clay is 0.66 and the NaF pH is 10 by weighted average throughout the particle size control section.
Typical Pedon was changed in September of 2004 to a site which better represents the central concept of the series.
ADDITIONAL DATA: NSSL, Lincoln Lab sample number 05N0017.
NASIS User Pedon ID: 04CA605REDW026
Soil classified using the 12th Edition of the Keys to Soil Taxonomy.
National Cooperative Soil Survey
U.S.A.