LOCATION GILLIGAN WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitrandic Dystroxerepts
TYPICAL PEDON: Gilligan ashy silt loam - on a 3 percent convex north-facing slope under a forest canopy. (Colors are for moist soil unless otherwise stated)
Oi--0 to 1 inch; needles, leaves and twigs.
A--1 to 5 inches; dark grayish brown (10YR 4/2) ashy silt loam, light brownish gray (10YR 6/2) dry; weak fine granular structure; slightly hard, very friable, slightly sticky, slightly plastic; very few very fine roots; common very fine irregular pores; strongly acid (pH 5.2); abrupt smooth boundary. (1 to 6 inches thick)
Bw1--5 to 12 inches; yellowish brown (10YR 5/4) ashy silt loam, pale brown (10YR 6/3) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; very few fine roots; common very fine tubular pores; strongly acid (pH 5.2); clear wavy boundary. (5 to 15 inches thick)
Bw2--12 to 23 inches; yellowish brown (10YR 5/6) ashy silt loam, light yellowish brown (10YR 6/4) dry; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; very few very fine roots; common very fine tubular pores; strongly acid (pH 5.4); abrupt wavy boundary (10 to 15 inches thick)
Bw3--23 to 33 inches; light olive brown (2.5Y 5/4) ashy silt loam, light gray (2.5Y 7/2) dry; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few coarse roots; few fine tubular pores; strongly acid (pH 5.2); clear wavy boundary. (8 to 14 inches thick)
C1--33 to 48 inches; olive (5Y 4/3) sandy loam, light gray (5Y 7/2) dry; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; very few very fine roots; few fine tubular pores; moderately acid (pH 5.6); abrupt smooth boundary. (8 to 18 inches thick)
2C2--48 to 61 inches; olive (5Y 4/3) extremely channery loamy sand, pale olive (5Y 6/3) dry; single grain; loose many fine irregular pores; 50 percent channers, 15 percent cobbles; moderately acid (pH 5.6)
TYPE LOCATION: Skagit County, Washington; 2,535 feet north and 1,400 feet east of the southwest corner of sec. 28, T. 35 N., R. 6 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 52 to 54 degrees F. These soils are usually moist but are dry in the moisture control section for 45 to 60 consecutive days. The control section averages 15 to 30 percent fine sand and coarser sand and 8 to 18 percent clay.
The A horizon has hues of 10YR or 7.5YR, value of 2 through 4 moist, 5 or 6 dry, and chroma of 2 through 4 moist and dry. Reaction is strongly acid or moderately acid.
The B horizon has hues of 2.5Y, 10YR, or 7.5YR, value of 4 through 6 moist, 6 or 7 dry, and chroma of 2 through 4 moist and dry. It is silt loam or very fine sandy loam. Reaction is strongly acid or moderately acid.
The C horizon has hues of 2.5Y or 5Y, values of 4 through 6 moist, 5 through 7 dry, and chroma of 2 or 3 moist and dry. Texture is sandy loam, loam or silt loam. Coarse fragments range from 0 to 15 percent.
The 2C horizon has hue of 5 Y or 2.5Y. Texture is very channery or extremely channery sand, loamy sand, or sandy loam. Coarse fragments range from 40 to 65 percent.
COMPETING SERIES: These are the Chaix, Elwha, Kickerville, Loper, Tethrick, Ulricher, Vader, and Yelm. Chaix, Elwha, and Loper soils have a paralithic contact at 20 to 40 inches. Kickerville soils have sand and gravel in the lower part of the control section. Tethrick soils are dry for 60 to 80 consecutive days, are slightly acid and have 5 to 20 percent rock fragments in the control section. Ulricher, Vader and Yelm soils are loam, sandy loam, or fine sandy loam in the B horizon and have more than 30 percent fine sand and coarser material in the control section. In addition, the Ulricher soils are dry for more than 60 consecutive days.
GEOGRAPHIC SETTING: Gilligan soils occur on stream terraces at elevations of 150 to 600 feet. The average annual precipitation ranges from 45 to 65 inches and the mean annual temperature is about 51 degrees F. Average January temperature is about 37 degrees F.; average July temperature is about 65 degrees F. The frost-free season is 180 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cokedale, Giles, and Larush soils. Cokedale soils lack cambic horizon and are somewhat poorly drained. Giles soils contain more than 18 percent clay. Larush soils have an umbric epipedon.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow. Permeability is moderate.
USE AND VEGETATION: Used as pasture and woodland. Native vegetation is Douglas-fir, western hemlock, western redcedar, bigleaf maple, blackberry, vine maple, western swordfern, and geranium.
DISTRIBUTION AND EXTENT: Northwestern Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Skagit County, Washington, 1953.
REMARKS: Classification changed 4/94 and 1/00 because of amendments to Soil Taxonomy. At 1 to 33 inches--estimated percent glass >5 and percent acid-oxalate extract of >0.4.
Diagnostic horizons and features are measured from the top of the first mineral layer.
Base saturation (NH4Oac) assumed to be less than 60 percent between 10 and 30 inches.