LOCATION TOKUL WA
Established Series
Rev. MK/AD/RJE
05/2017
TOKUL SERIES
Landscape--hills
Landform--till plains, hillslopes
Slope--0 to 90 percent
Parent material--loess and volcanic ash over dense glacial till cemented with iron and manganese
Mean annual precipitation--about 1500 mm
Mean annual air temperature--about 9 degrees C
Depth class--moderately deep
Drainage class--moderately well drained
Soil moisture regime--xeric
Soil temperature regime--mesic
Soil moisture subclass--aquic
TAXONOMIC CLASS: Medial, amorphic, mesic Aquic Vitrixerands
TYPICAL PEDON: Tokul gravelly medial loam, forested (All textures are apparent field textures.)
Oi--0 to 3 cm; forest litter consisting of leaves and twigs.
Oa--3 to 5 cm; black (10YR 2/1) decomposed litter.
A--5 to 15 cm; gravelly medial loam, yellowish brown (10YR 5/4) dry, dark brown (7.5YR 3/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and nonplastic, weakly smeary; common very fine, fine, and medium and few coarse roots; common very fine discontinuous pores; 5 percent medium rounded concretions; 15 percent gravel; moderately acid (pH 5.8); abrupt wavy boundary
Bs1--15 to 23 cm; gravelly medial loam, light brown (7.5YR 6/4) dry, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic, weakly smeary; common very fine, fine, and medium and few coarse roots; common very fine discontinuous pores; 5 percent fine and medium rounded concretions; 15 percent gravel; slightly acid (pH 6.2); clear smooth boundary
Bs2--23 to 43 cm; gravelly medial loam, light yellowish brown (10YR 6/4) dry, strong brown (7.5YR 5/6) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic, weakly smeary; common very fine, fine, and medium and few coarse roots; common very fine discontinuous pores; 5 percent fine and medium rounded concretions; 15 percent gravel; slightly acid (pH 6.2); clear smooth boundary
Bs3--43 to 61 cm; gravelly medial loam, very pale brown (10YR 7/4) dry, dark yellowish brown (10YR 4/4) moist; common medium distinct yellowish brown (10YR 5/8) redoximorphic concentrations; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; few very fine, fine, medium, and coarse roots; common very fine discontinuous pores; 3 percent fine rounded concretions; 20 percent gravel and 10 percent cobbles; slightly acid (pH 6.2); abrupt smooth boundary
BC--61 to 84 cm; gravelly medial fine sandy loam, pale yellow (2.5Y 8/4) dry, light olive brown (2.5Y 5/4) moist; common fine distinct yellowish brown (10YR 5/8) redoximorphic concentrations; massive; slightly hard, friable, slightly sticky and nonplastic; weakly smeary; few very fine, fine, medium, and coarse roots; common very fine discontinuous pores; 1 percent fine irregularly shaped concretions; 25 percent gravel and 5 percent cobbles; moderately acid (pH 6.0); abrupt smooth boundary
2Bsm--84 to 157 cm; very gravelly sandy loam, light gray (2.5Y 7/2) dry, dark grayish brown (2.5Y 4/2) moist; common medium distinct yellowish brown (10YR 5/8) redoximorphic concentrations; massive; hard, extremely firm, weakly cemented, extremely hard in places; 35 percent gravel; very thin (0.55 mm) discontinuous indurated layer on surface of horizon; moderately acid (pH 6.0)
TYPE LOCATION: Snohomish County, Washington; about 670 m east and 320 m north of the southwest corner section 6, T. 28 N., R. 7 E.; latitude 47.9380, longitude -121.9610, datum WGS 84 (coordinates estimated from PLSS details)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--8 to 10 degrees C
Moisture control section--dry 45 to 60 consecutive days following summer solstice in most years
Depth to densic horizon--50 to 100 cm
Depth to cemented horizon--50 to 100 cm
Depth to redoximorphic concentrations--43 to 100 cm
Particle-size control section (weighted average)
*Clay content--2 to 15 percent
*Rock fragment content--15 to 35 percent total, including 10 to 30 percent gravel and 0 to 15 percent cobbles
Estimated properties of layers influenced with volcanic ash
*Volcanic glass content in 0.02 to 2.0 mm fraction--5 to 20 percent
*Ammonium oxalate extractable Al + 1/2 Fe--2 to 4 percent
*Phosphate retention--85 to 90 percent
*1/3-bar bulk density--0.6 to 0.9 g/cm3
*1500 kPa water (air-dried samples)--12 to 15 percent
A horizon
Hue--10YR, 7.5YR
Value--2 to 4 moist, 4 to 6 dry
Chroma--1 to 3 moist or dry
Fine-earth texture--medial loam, medial fine sandy loam, medial sandy loam
Clay content--5 to 20 percent
Total rock fragment content--10 to 30 percent
Gravel content--10 to 30 percent
Cobble content--0 to 5 percent
Reaction--5.1 to 6.5
Thickness--3 to 10 cm
Some pedons have an E horizon.
Bs horizon (sometimes described as Bw horizon)
Hue--10YR, 7.5YR
Value--3 to 6 moist, 4 to 7 dry
Chroma--4 to 6 moist or dry
Fine-earth texture--medial loam, medial fine sandy loam, medial sandy loam, medial coarse sandy loam
Clay content--2 to 15 percent
Total rock fragment content--10 to 35 percent
Gravel content--10 to 30 percent
Cobble content--0 to 15 percent
Concretion content--0 to 10 percent
Reaction--5.1 to 6.5
Combined thickness--29 to 104 cm
BC horizon
Hue--2.5Y, 5Y
Value--4 to 6 moist, 5 to 8 dry
Chroma--2 to 4 moist or dry
Fine-earth texture--medial fine sandy loam, medial loam, medial sandy loam, medial coarse sandy loam
Clay content--1 to 15 percent
Total rock fragment content--20 to 60 percent
Gravel content--20 to 50 percent
Cobble content--0 to 15 percent
Reaction--5.1 to 6.5
Thickness--13 to 36 cm
2Bsm horizon
Value--4 or 5 moist, 6 or 7 dry
Chroma--2 or 3 moist or dry
Fine-earth fraction--sandy loam, fine sandy loam, coarse loamy sand
Clay content--1 to 15 percent
Total rock fragment content--30 to 60 percent
Gravel content--30 to 50 percent
Cobble content--0 to 15 percent
Reaction--5.1 to 6.5
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--50 to 450 m
Mean annual precipitation--1100 to 1800 mm
Mean January air temperature--1 degree C
Mean July air temperature--15 degrees C
Mean annual air temperature--8 to 11 degrees C
Frost-free period--140 to 200 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Barneston--no ortstein layer; more than 150 cm thick; sandy-skeletal
Pastik--no ortstein layer; more than 150 cm thick; coarse-silty
Ragnar--no ortstein layer; more than 150 cm thick
Winston--no ortstein layer; more than 150 cm thick
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained
Saturated hydraulic conductivity (Ksat)--moderately low or moderately high above ortstein layer, very low in densic layer
Depth to perched water table--46 to 100 cm at times in November through May
USE AND VEGETATION:
Use--mostly timber production and pasture
Native vegetation--Douglas-fir, western hemlock, western redcedar, bigleaf maple, red alder, western swordfern, salal, vine maple, red huckleberry, trailing blackberry, Pacific trillium, western brackenfern, salmonberry, deer fern, ladyfern, Oregongrape
DISTRIBUTION AND EXTENT: West slopes of Cascade Mountains in northwestern Washington; large extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: King County, Washington; 1943
REMARKS:
Diagnostic horizons and other features in this pedon
*Ochric epipedon
*Cambic horizon--zone from 15 to 61 cm
*Redoximorphic concentrations--zone from 43 to 157 cm
*Andic soil properties--zone from 5 to 84 cm
*Particle-size control section--zone from 5 to 84 cm
*Depth to dense glacial till cemented with iron and manganese--84 to 157 cm
This series is the designated state soil for Washington State.
7/2013--The Tokul official series description (OSD) was updated as part of a soil data join recorrelation project. The classification was not changed, but the OSD was reformatted and English units were converted to metric units. Laboratory data indicates that the andic soil properties may not always extend to the cemented till and a strongly contrasting particle-size class may be warranted. Further field investigation and laboratory sampling is recommended. The cementing agents in the 2Bsm horizon also require additional investigation. In some historic surveys that included the Tokul series, this material was recognized as ortstein.
12/2015--This OSD was updated according to SSR01 Technical Note--Content and Format of Official Series Descriptions (revised 12/2015). Most of the changes were in formatting; no major technical changes were made.
ADDITIONAL DATA: S98WA-061-001
National Cooperative Soil Survey
U.S.A.