LOCATION WOODINVILLE WAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, nonacid, mesic Aeric Fluvaquents
TYPICAL PEDON: Woodinville silt loam, pasture. (Colors are
for moist soil unless otherwise noted.)
Ap1--0 to 3 inches; very dark grayish brown (2.5Y 3/2)
silt loam, grayish brown (2.5Y 5/2) dry; common fine
prominent dark reddish brown (5YR 3/4) and reddish brown
(5YR 5/4) mottles; moderate medium crumb structure; hard,
friable, slightly sticky, slightly plastic; many fine roots;
few medium pores; moderately acid (pH 5.8); clear smooth
boundary.
Ap2--3 to 8 inches; very dark grayish brown (2.5Y 3/2)
silt loam, light brownish gray (2.5Y 6/2) dry; many fine
prominent dark reddish brown (5YR 3/3 and 3/4) mottles;
moderate fine and very fine angular blocky structure; hard,
friable, slightly sticky, slightly plastic; common fine
roots; common medium pores; moderately acid (pH 5.6); abrupt
wavy boundary. (combine thickness of the Ap horizon is 6 to
10 inches))
Cg1--8 to 38 inches; dark grayish brown (2.5Y 4/2) silt
loam, light brownish gray (2.5Y 6/2) dry; common fine
prominent brown (7.5YR 4/4) mottles; 25 percent lenses of
very dark brown (10YR 2/2) and dark yellowish brown (10YR
3/4) sapric material, brown (7.5YR 4/2) dry; massive; hard,
friable, slightly sticky, slightly plastic; few fine roots;
few medium pores; moderately acid (pH 5.6); clear smooth
boundary. (28 to 40 inches thick)
Cg2--38 to 60 inches; dark gray (5Y 4/1) silt loam, gray
(5Y 6/1) dry; few fine prominent mottles of brownish yellow
(10YR 6/6) dry; massive; hard, very friable, slightly
sticky, slightly plastic; few fine roots; strongly acid (pH
5.4).
TYPE LOCATION: King County, Washington; about 3 miles
northwest of Carnation, 1,700 feet south and 2,240 feet east
of the northwest corner, section 6, T.25N., R.7E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature
is estimated to range from 47 to 52 degrees F. The
particle-size control section averages 0 to 5 percent coarse fragments, less than 15 percent fine and coarser sand, and
18 to 32 percent clay. The particle-size control section
contains thin (less than 1/4 inch to 2 inches) lenses of
organic material totaling 1 to 15 inches in combined
thickness.
The Ap horizon has hue of 10YR, 2.5Y, or 5Y, value of 2 to 5
moist, 5 to 7 moist, and chroma of 1 or 2 moist or dry, and
has many prominent mottles of 7.5YR and 5YR hue and chroma
of 3 through 6. It is strongly acid or moderately acid.
Some pedons have a Bg horizon.
The Cg horizon, immediately below the Ap horizon, has hue of
2.5Y or 5Y, value of 3 to 5 moist, 5 to 8 dry and has
prominent mottles of dark reddish brown (5YR 3/4), yellowish
red (5YR 4/6, 4/8), strong brown (7.5YR 5/6), dark brown
(7.5YR 4/4), and yellowish red (10YR 5/6). Below 12 inches
the Cg horizon has hue of 2.5Y, 4Y, or N value of 3 to 6
moist, 5 to 8 dry, and chroma of 0 to 2 moist or dry. It is
not mottled in some pedons. It ranges from silty clay loam
to silt loam and has thin lenses of fine sandy loam and
loamy fine sand in some pedons. This horizon has moderate
medium angular blocky structure or is massive. It is
moderately acid to very strongly acid.
COMPETING SERIES: These are the
Ackmore,
Newark,
Puget, and
Rahm soils. All of these soils lack sapric lenses within
the particle-size control section. In addition, Ackmore
soils have a buried mollic epipedon in the particle-size
control section. Newark and Rahm soils have a mean annual
soil temperature of about 57 degrees F. Rahm soils also
have a buried 2B horizon in the particle-size control
section.
GEOGRAPHIC SETTING: The Woodinville soils are on flood
plains and low terraces in river valleys with slightly
undulating microrelief at elevations ranging from near sea
level to about 85 feet. They formed in stratified recent
alluvium. The average January temperature is 38 degrees F;
the average July temperature is 64 degrees F; and the
average annual temperature is about 50 degrees F. The
average annual precipitation ranges from 35 to 55 inches,
most of which falls as rain during the winter. Each month
of summer has at least 1 inch of rainfall. Snow is
infrequent. The frost free season is 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Puget soils, and the
Puyallup and
Snohomish soils. Puyallup
soils have a mollic epipedon, a xeric moisture regime, and
are coarse-loamy over sandy or sandy-skeletal. Snohomish
soils have a buried histic epipedon.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff;
moderately slow permeability.
USE AND VEGETATION: Most of the Woodinville soils have been
cleared and drained and used for cropland. Seeded grass
pasture or corn for silage and grass legume hay are common
crops. The native vegetation is red alder, western
redcedar, and black cottonwood, with an understory of
willow, Douglas spirea, rush, sedge, western brackenfern,
devilsclub, western swordfern, salal, and vine maple.
DISTRIBUTION AND EXTENT: The series is of small extent;
King County, Washington.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: King County, Washington, 1943.
REMARKS: Diagnostic horizons and features recognized in
this pedon are an ochric epipedon from the surface to 8
inches, a particle-size control section from 10 to 40 inches
that has an irregular decrease in organic carbon and more
than 0.2 percent organic carbon at a depth of 60 inches.