LOCATION ZYLSTRA WA

Established Series
Rev. CAB/TMR/SBC
06/2011

ZYLSTRA SERIES

The Zylstra series consists of moderately deep to densic contact, somewhat poorly drained soils formed in compacted glacial drift underlain by dense glaciomarine deposits. Zylstra soils are on hillslopes and outwash plains at elevations from 40 to 90 meters. Slopes are 0 to 15 percent. The mean annual precipitation is about 813 mm. The mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Aquic Humixerepts

TYPICAL PEDON: Zylstra loam, forested, on a nearly level glacial outwash plain at 60 meters elevation. When described on August 7, 2005 the soil was dry from the surface to the lower part of the Bg1 horizon and slightly moist in the Bg2 and Cd. (Colors are for dry soil unless otherwise noted.)

A1--0 to 10 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate coarse granular structure and moderate medium granular structure; slightly hard, very friable, slightly sticky, slightly plastic; many very fine and fine and common medium and coarse roots; many medium irregular and interstitial pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary.

A2--10 to 30 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine and fine and few medium roots; common very fine and fine irregular and interstitial pores; 10 percent gravel; moderately acid (pH 5.6); abrupt wavy boundary. (Combined thickness of the A horizons is 25 to 38 cm)

E--30 to 46 cm; light brownish gray (10YR 6/2) sandy loam, grayish brown (10YR 5/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine, fine, and medium roots; common very fine and fine pores; many distinct yellowish brown (10YR 5/4), dark yellowish brown (10YR 4/6) moist, iron-manganese masses in matrix surrounding depletions; many distinct light gray (2.5Y 7/1) sandy loam, gray (2.5Y 5/1) moist, iron depletions with clear boundaries throughout; 10 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (13 to 28 cm thick)

Bg1--46 to 81 cm; light brownish gray (2.5Y 6/2) gravelly sandy loam, grayish brown (2.5Y 5/2) moist; moderate medium angular blocky structure; moderately hard, friable, slightly sticky, slightly plastic; few very fine and fine roots; many very fine and fine irregular pores; many faint light brownish gray (2.5Y 6/2), light grayish brown (2.5Y 5/2) moist, iron depletions in matrix; many brown (7.5YR 5/4), distinct brown (7.5YR 4/4) moist, iron-manganese masses in matrix; 15 percent gravel; slightly acid (pH 6.4); gradual wavy boundary.

Bg2--81 to 94 cm; light brownish gray (2.5Y 6/2) gravelly loam, grayish brown (2.5Y 5/2) moist; strong coarse angular blocky structure; very hard, very firm, slightly sticky, slightly plastic; few very fine roots in cracks; many very fine irregular and interstitial pores; common prominent very dark gray (10YR 3/1), black (10YR 2/1) moist, organoargillans on all faces of peds; many coarse distinct reddish yellow (5YR 6/6), yellowish red (5YR 4/6) moist, iron-manganese masses with clear boundaries in matrix; many prominent light gray (2.5Y 7/1), gray (2.5Y 6/1) moist, iron depletions in matrix; 20 percent gravel; neutral (pH 7.2); gradual wavy boundary. (Combined thickness of the Bg horizons is 23 to 64 cm)

Cd--94 to 152 cm; light brownish gray (2.5Y 6/2) gravelly sandy loam, dark grayish brown (2.5Y 4/2) moist; massive; hard, firm, nonsticky, nonplastic; few very fine irregular pores; neutral (pH 7.3); 15 percent gravel.

TYPE LOCATION: Island County, Washington; 275 meters east and 314 meters north of SW corner of section 60, T32N, R1E; Willamette Meridian; USGS Coupeville, Washington quadrangle; lat. 48 degrees, 14 minutes, 32 seconds N. and long. 122 degrees, 44 minutes, 32 seconds W.

RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.

Mean annual soil temperature - 10 to 11 degrees C
Depth to redoximorphic features - 23 to 46 cm
Umbric epipedon thickness - 25 to 38 cm
Depth to densic contact - 50 to 100 cm
Reaction - strongly acid to neutral
Particle size control section:
Clay content - 5 to 18 percent
Rock fragments - 0 to 25 percent gravel and 0 to 10 percent cobbles

A1 horizon
Hue - 10YR or 7.5YR
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Clay content - 5 to 10 percent

A2 Horizon
Hue - 10YR or 7.5YR
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Texture - L, FSL, SL
Clay content - 5 to 10 percent
Rock fragments - 0 to 15 percent

E horizon
Hue - 10YR or 2.5Y
Value - 4 to 5 moist, 6 or 7 dry
Chroma - 1 or 2 moist and dry
Texture - SL, FSL or L
Clay content - 2 to 10 percent
Rock fragments - 0 to 20 percent gravel

Bg1 horizon
Hue - 10YR or 2.5Y
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 2 to 4 moist and dry
Texture - SL, FSL or L
Clay content - 3 to 18 percent
Rock fragments - 5 to 20 percent gravel and 0 to 10 percent cobbles

Bg2 horizon
Hue 10YR or 2.5Y
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 2 to 4 moist and dry
Texture - SL, FSL or L
Clay content - 6 to 18 percent
Rock fragments - 5 to 25 percent gravel and 0 to 10 percent cobbles

Cd horizon
Hue 2.5Y or 5Y
Value - 4 to 5 moist, 5 to 7 dry
Chroma - 1 to 3 moist and dry
Texture - SL or L
Clay content - 4 to 18 percent
Rock fragments - 5 to 20 percent gravel and 0 to 10 percent cobbles

COMPETING SERIES: These are the Morancreek and Roche series. Morancreek soils do not have a densic contact, and are 38 to 75 cm to redoximorphic features. Roche soils have an ochric epipedon, and are 46 to 91 cm to redoximorphic features.

GEOGRAPHIC SETTING: Zylstra soils are on hills and outwash plains. Slopes range from 0 to 15 percent. These soils are formed in compacted glacial drift underlain by dense glaciomarine deposits. Elevations range from 40 to 90 meters. These soils occur in a mild marine climate with warm dry summers and mild wet winters. The mean annual precipitation is about 635 to 1016 mm, most of which falls as rain in the late fall, winter and early spring. The mean annual temperature is about 9 degrees C. The frost-free period is about 200-240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Coveland and Mitchellbay series. Coveland soils are in drainageways and valleys on glacial outwash plains. Coveland soils are fine-loamy and do not have a densic contact above 100 cm. Mitchellbay soils are on similar landscape positions as Zylstra soils. Mitchellbay soils are fine-loamy and have an argillic horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Saturated hydraulic conductivity is high to very high in the A, E, and Bg horizons, and very low in the Cd horizon. Zylstra soils have a perched water table as high as 23 cm from December through February and from 46 to 81 cm during October and March. At lower slope ranges, Zylstra soils are subject to occasional ponding for very brief durations from December to March.

USE AND VEGETATION: Zylstra soils are used for home sites, timber production, crop production, and livestock grazing. Potential natural vegetation is western redcedar, Douglas-fir, grand fir, lodgepole pine, red alder, common snowberry, trailing blackberry, salmonberry, stinging nettle, salal, swordfern, and bracken fern.

DISTRIBUTION AND EXTENT: Northwestern Washington; MLRA 2. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Island County, Washington, 2009.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - the zone from 0 to 30 cm (A1 and A2 horizons)
Albic horizon - the zone from 30 to 46 cm (E horizon)
Densic contact - 94 cm. (upper boundary of Cd horizon)
Particle size control section - 25 to 94 cm (to the Cd horizon)
Depth to redoximorphic features - 30 cm

Most of the area mapped as Zylstra was previously mapped as Swantown in the 1950 Island County soil survey. Swantown soils are loamy-skeletal and have a Bsm, or cemented horizon.

National Cooperative Soil Survey
U.S.A.