LOCATION YELM WAEstablished Series
TAXONOMIC CLASS: Ashy, amorphic, acid, mesic Typic Vitraquands
TYPICAL PEDON: Yelm fine sandy loam - in a cultivated field at an elevation of 200 feet. The soil was moist when described. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; dark brown (7.5YR 3/2) fine sandy loam; grayish brown (10YR 5/2) dry; moderate very fine subangular blocky structure, soft, very friable, nonsticky, nonplastic; many fine roots; many very fine irregular pores; 20 percent shot-like aggregates; NaF pH 11.5; moderately acid (pH 5.8); abrupt smooth boundary. (7 to 9 inches thick)
Bs1--8 to 17 inches; dark yellowish brown (10YR 4/4) fine sandy loam; pale brown (10YR 6/3) dry; few faint greenish gray (5GY 6/1) mottles; weak very fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common fine roots; many very fine irregular pores; NaF pH 11.5: moderately acid (pH 6.0); clear wavy boundary. (7 to 9 inches thick)
Bs2--17 to 36 inches; dark grayish brown (2.5Y 4/2) fine sandy loam light brownish gray (2.5Y 6/2) dry; few fine faint, very dark grayish brown (2.5Y 3/2) organic masses 1 to 2 inches in diameter, and few fine faint greenish gray (5GY 6/1) mottles, weak very fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; few fine roots; many very fine irregular pores; NaF pH 12.0; moderately acid (pH 6.0); gradual wavy boundary. (17 to 21 inches thick)
Bs3--36 to 46 inches; olive brown (2.5Y 4/4), fine sandy loam; grayish brown (2.5Y 5/2) dry; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine roots; many very fine irregular pores; NaF pH 10.5; moderately acid (pH 6.0); abrupt smooth boundary. (8 to 12 inches thick)
2C--46 to 60 inches; light olive brown (2.5Y 5/4) loamy sand, light gray (2.5Y 7/2) dry; loose, NaF pH 10.5; slightly acid (pH 6.2).
TYPE LOCATION: Thurston County, Washington; two miles southeast of Olympia on east side of Boulevard Road; 950 feet east, 1,950 feet south of the northwest corner of sec. 31, T. 18 N., R. 1 W., W.M.
RANGE IN CHARACTERISTICS: Mean annual soil temperature at 20 inches ranges from 48 to 54 degrees F. Thickness of volcanic ash influence and depth to the 2C horizon ranges from 20 to 50 inches. These soils are usually moist, but are dry for 60 to 75 days in all parts of the moisture control section following the summer solstice. Mottles with a chroma of 2 or less are within 30 inches of the surface. These soils are moderately acid or slightly acid throughout.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist or dry.
The Bs horizon has hue of 7.5YR through 5Y, value of 3 through 5 moist 5 through 8 dry, and chroma of 2 through 4 moist and dry. It has faint mottles. Some mottles have a chroma of 2 or less. It is fine sandy loam, loam, or very fine sandy loam, and contains lenses of silt loam and loamy sand in some pedons.
The C horizon has hue of 2.5Y or 5Y, value of 4 through 7 moist, 5 through 7 dry, and chroma of 2 through 4 moist and dry. It is mottled in some pedons. It is stratified loamy sand, silt loam, fine sand, and sandy loam in some pedons.
COMPETING SERIES: These are the Clipper soils and the Hale, Laxton, Pastik and Roche series in other families. Clipper soils are very gravelly in the lower part of the particle-size control section. Hale and Yelm soils are coarse-loamy over sandy or sandy-skeletal. Pastik soils are less than 15 percent sand coarser than very fine sand in the particle-size control section. Roche soils have a very hard and very firm, slowly permeable substratum within the particle-size control section.
GEOGRAPHIC SETTING: Yelm soils are on glacial outwash terraces at elevations of 25 to 300 feet. Slopes are 0 to 30 percent. These soils formed in loess and volcanic ash and glacial outwash. Yelm soils are in a marine climate with cool, dry summers and mild, wet winters. Average annual precipitation is 30 to 60 inches. Mean January temperature is 37 degrees F; mean July temperature is 63 degrees F. Mean annual air temperature is about 51 degrees F. The frost-free season is 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cagey, Giles, Indianola, Lynnwood, Norma, and Skipopa soils. Cagey, Indianola, and Lynnwood soils are sandy. Giles soils lack grayish mottles in the particle-size control section. Norma soils are coarse-loamy and have an aquic moisture regime. Skipopa soils are medial over clayey.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to medium runoff; moderately rapid permeability. An apparent high water table is as high as 1.5 to 3 at times feet from November to March, and drops below the root zone during most of the growing season.
USE AND VEGETATION: Used mostly for cropland. Hay, grain, and specialty crops are common crops. Native vegetation consisted of Douglas-fir, red alder, western redcedar and bigleaf maple with an understory of salal, Oregon-grape, trailing blackberry, red huckleberry, western brackenfern, western swordfern, salmonberry and vine maple.
DISTRIBUTION AND EXTENT: Puget lowlands in northwestern Washington. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Thurston County, Washington, 1982.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy. This draft reflects a change in classification from coarse-loamy, mixed, mesic Aquic Haplorthods to ashy, mesic Typic Vitraquands. Estimated at depth of 0 to 46 inches a content of 5 to 20 percent volcanic glass and 1.0 to 2.0 percent Al + 1/2 Fe by acid-oxalate. Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the surface to 8 inches and a cambic horizon from 8 to 46 inches with grayish mottles from 17 to 36 inches.