LOCATION BRISCOT WA+CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, mesic Fluvaquentic Endoaquepts
TYPICAL PEDON: Briscot silt loam-cultivated (Colors are for moist soil unless otherwise noted)
Ap--0 to 9 inches; dark grayish brown (10YR 4/2) silt loam, grayish brown (10YR 5/2) dry; moderate medium granular structure; slightly hard, friable, moderately sticky and moderately plastic; many roots; few fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (8 to 10 inches thick)
Bg--9 to 17 inches; grayish brown (2.5Y 5/2) silt loam, light brownish gray (2.5Y 6/2) dry; many large prominent dark brown (7.5YR 4/4 and 3/4) redox concentrations, brownish yellow (10YR 6/6) dry; weak very coarse prismatic structure; slightly hard, friable, moderately sticky and moderately plastic; common roots; many fine tubular pores; neutral (pH 6.6); abrupt wavy boundary. (7 to 9 inches thick)
Cg1--17 to 44 inches; grayish brown (2.5Y 5/2) finely stratified silt loam, fine sand, and fine sandy loam, light brownish gray (2.5Y 6/2) dry; many large prominent brown (7.5YR 4/4) redox concentrations, yellowish brown (10YR 5/6) and light yellowish brown (10YR 6/4) dry; massive; slightly hard, very friable, slightly sticky, nonplastic; few roots; many fine tubular pores; neutral (pH 6.8); diffuse smooth boundary. (25 to 28 inches thick)
Cg2--44 to 60 inches; dark gray (5Y 4/1) finely stratified silt loam, fine sand and fine sandy loam, grayish brown (2.5Y 5/2) dry; many large prominent brown (7.5YR 4/4) and dark red (2.5YR 3/6) redox concentrations, brown (7.5YR 5/4) and yellowish brown (10YR 5/6) dry; massive; very friable, slightly sticky, nonplastic; few roots; common fine tubular and many very fine interstitial pores; neutral (pH 6.8).
TYPE LOCATION: King County, Washington, 1,000 feet north and 1,410 feet east of southwest corner sec. 25, T. 22N., R. 4 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 48 to 54 degrees F. The particle-size section contains 5 to 15 percent clay, and 0 to 2 percent coarse fragments. These soils are usually moist, and contain irregular distribution of organic matter with depth. It is slightly acid or neutral throughout. More than 40 percent of the soil between a depth of 10 and 30 inches has a hue of 2.5Y, a value moist of 5 or less, and chroma of 2.
The Ap horizon has hue of l0YR or 2.5Y, value of 3 or 4 moist, 5 through 7 dry, and chroma of 2 or 3 moist and dry. It has weak or moderate granular or blocky structure.
The Bg horizon has hue of 2.5Y or 5Y, and value of 4 through 7 moist and dry, and chroma of 1 or 2 moist and dry. Redox features have hue of 2.5YR through 2.5Y, value of 3 through 5 moist, 4 or 5 dry and chroma of 4 through 6 moist and dry.
The Cg horizon has hue of 2.5Y or 5Y, and value of 4 through 7 moist and dry, and chroma of 1 or 2 moist and dry. Redox features have hue of 2.5YR through 2.5Y, value of 3 through 5 moist, 4 or 5 dry, and chroma of 4 through 6 moist and dry. This horizon is stratified with layers of silt loam, fine sand, sand, and fine sandy loam.
COMPETING SERIES: These are the Hockinson and Rippowan series. Rippowan soils have less than 8 percent clay in the particle-size control section. Hockinson soils have surface colors of 2 or 3 moist value, and 0 to 2 moist chroma (Mollic subgroup).
GEOGRAPHIC SETTING: These soils are on floodplains in river valleys at elevations of 20 to 250 feet. The soils formed in recent alluvium. Briscot soils occur in a humid climate with an average January temperature of 38 degrees F.; average July temperature is 64 degrees F.; and mean annual temperature is 50 degrees F. The frost-free season is 160 to 210 days. The average annual precipitation ranges from 30 to 55 inches, most of which falls as rain during the winter months. Each of the summer months generally has at least 1 inch of rainfall. Snow is infrequent.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Oridia, Puget, Puyallup, Renton, Skagit, and Woodinville soils. Oridia soils are coarse silty. Puget, Skagit and Woodinville soils have more than 18 percent clay in the particle-size control section. Puyallup and Renton soils are coarse-loamy over sandy or sandy-skeletal.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow runoff; moderate permeability. These soils are subject to occasional, brief flooding from November through April. An apparent water table is at 0 to 1 foot from November through April unless drained.
USE AND VEGETATION: Most soils are drained and used for cropland. Row crops and seeded grass pasture are common crops. Native vegetation was western redcedar, western hemlock, red alder, and Douglas-fir with an understory of western swordfern, salal, vine maple, western brackenfern, trailing blackberry, rose, northern bedstraw, and northern twinflower.
DISTRIBUTION AND EXTENT: Northwestern Washington. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: King County, Washington, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the surface to 9 inches, and a cambic horizon from 9 to 17 inches.