LOCATION NEWAUKUM WAEstablished Series
TAXONOMIC CLASS: Medial, mixed, mesic Humic Haploxerands
TYPICAL PEDON: Newaukum gravelly silt loam - under a coniferous forest on a 26 percent convex west-facing upper back slope at an elevation of l,680 feet. (The soil was moist when described. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
0e--2 inches to 0; loose, partially decomposed organic litter, including needles, leaves, twigs, bark chips, and cones; abrupt smooth boundary. (l to 4 inches thick)
A--0 to 9 inches; very dark brown (l0YR 2/2) gravelly silt loam, dark brown (l0YR 4/3) dry; moderate silt fine subangular blocky structure parting to moderate fine granular; soft, very friable, slightly sticky, slightly plastic and weakly smeary; many very fine, fine, medium, and coarse roots; many very fine irregular pores; 20 percent rounded and subangular unweathered pebbles, l0 percent rounded shot-like aggregates (2-5 mm in diameter); moderately acid (pH 6.0); abrupt wavy boundary. (4 to l2 inches thick)
Bwl--9 to l6 inches; dark brown (l0YR 3/3) gravelly silt loam, yellowish brown (l0YR 5/4) dry; moderate medium parting to very fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; many very fine, fine, medium, and coarse roots; many fine tubular pores; 25 percent rounded and subangular unweathered pebbles and few cobbles; moderately acid (pH 6.0); clear wavy boundary.
Bw2--l6 to 25 inches; dark yellowish brown (l0YR 3/4) gravelly silt loam, light yellowish brown (l0YR 6/4) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; common fine, many medium and coarse roots; common fine tubular pores; 25 percent rounded and subangular unweathered pebbles and few cobbles; slightly acid (pH 6.2); clear irregular boundary.
Bw3--25 to 4l inches; dark yellowish brown (l0YR 4/4) gravelly loam, very pale brown (l0YR 7/4) dry; moderate coarse subangular blocky structure; hard, friable, slightly sticky, nonplastic and weakly smeary; common fine, medium, and coarse roots; few fine tubular pores; 25 percent rounded and subangular unweathered pebbles, 5 percent soft pumice fragments (2-l0 mm in diameter); neutral (pH 6.6); clear wavy boundary. (Combined thickness of the Bw horizon is 27 to 40 inches)
BC--4l to 5l inches; strong brown (7.5YR 4/6) gravelly silt loam, reddish yellow (7.5YR 6/6) dry; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few fine, common medium and coarse roots; few fine tubular pores; 20 percent rounded and subangular unweathered pebbles, l0 percent unweathered cobbles; slightly acid (pH 6.2); clear wavy boundary. (6 to l9 inches thick)
C--5l to 60 inches; dark brown (7.5YR 4/4) very cobbly silt loam, pink (7.5YR 7/4) dry; massive; hard, friable, slightly sticky, slightly plastic and weakly smeary; few roots; few pores; l0 percent rounded and subangular unweathered pebbles, 40 percent cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Lewis County, Washington; 2,640 feet south and 2,l00 feet east of the northwest corner of section 23, T. l2 N., R. 4 E., W.M.
RANGE IN CHARACTERISTICS: Average annual soil temperature at a depth of 20 inches ranges from 47 to 53 degrees F. The umbric epipedon is l0 to 20 inches thick. These soils are usually moist, but are dry in all parts between depths of 8 and 24 inches from 45 to 60 consecutive days following the summer solstice. Hue is 7.5YR or l0YR throughout. The particle-size control section has l5 to 25 percent unweathered pebbles and 0 to l0 percent unweathered cobbles.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is gravelly silt loam or gravelly loam and has l5 to 25 percent unweathered pebbles and 0 to 5 percent unweathered cobbles. Weathered pumice fragments range from 0 to l0 percent. This horizon is moderately acid to neutral.
The Bw horizon has value of 3 or 4 moist, 4 to 7 dry, and chroma of 3 to 6 moist and dry. Texture is gravelly silt loam or gravelly loam unweathered pebbles average from 15 to 25 percent and cobbles from 0 to 10 percent. Highly weathered (soft) pumice fragments range from 0 to 10 percent.
The BC horizon has value of 4 or 5 moist, 5 through 7 dry, and chroma of 4 through 6 moist and dry. It is gravelly silt loam or gravelly loam and has l5 to 20 percent unweathered pebbles and 0 to l0 percent unweathered cobbles. Weathered pumice fragments range from 0 to l0 percent. This horizon is moderately acid to neutral.
The C horizon, when present, has value of 4 or 5 moist, 6 or 7 dry, and chroma of 4 through 6 moist and dry. It is gravelly, very gravelly, or very cobbly, silt loam or loam. Unweathered rock fragments range from l5 to 50 percent. This horizon is moderately acid to neutral.
COMPETING SERIES: There are no competing series. Similar soils in other families are the Bear Prairie, Calawah, Cinebar, Hemcross, Lebar, Lytell, Mossyrock, Quillayute, Trouter, and Winema series. Bear Prairie, Mossyrock, Quillayute and Winema soils have an umbric epipedon more than 20 inches thick. Calawah, Hemcross, Lebar, and Lytell soils have a udic moisture regime. Cinebar soils have less than l5 percent unweathered rock fragments in the particle-size control section. Trouter soils are 20 to 40 inches deep to a lithic contact.
GEOGRAPHIC SETTING: Newaukum soils are on mountains and foothills at elevations of 300 to l,800 feet. Slope is 5 to 90 percent. These soils formed in colluvium or glaciofluvial deposits of volcanic ash and rock flour including lahar or mud flow material with a high content of ash and pumice, with an admixture of aerially deposited volcanic ash. The climate is characterized by cool, dry summers and mild, wet winters. Average annual precipitation is 60 to 75 inches. Average annual temperature is 46 to 50 degrees F. The frost-free season (32 degrees F.) is l50 to 200 days. The growing season (28 degrees F.) is l50 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Cinebar and Mossyrock soils, and the Baumgard, Domell, Hoffstadt, Nesika, Schneider, and Zynbar soils. Baumgard soils are fine-loamy. Domell and Zynbar soils have a frigid temperature regime. Hoffstadt soils are medial-skeletal and have a frigid temperature regime. Nesika and Schneider soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat, and watershed. A few areas are used for cropland and homesites. Overstory vegetation is Douglas-fir, western redcedar, western hemlock, bigleaf maple, and red alder. Understory vegetation is vine maple, Oregongrape, western swordfern, trailing blackberry, red huckleberry, salal, Pacific trillium, devilsclub, western brackenfern, insideout flower, violet, bedstraw, salmonberry, mosses, and lichens.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in southwestern Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lewis County, Washington, l979.
REMARKS: Classification only updated 3/94 because of recent amendments to Soil Taxonomy. This description reflects a change in classification based on amendment 16. Diagnostic horizons or features recognized in this pedon are an umbric epipedon from the mineral surface to 16 inches and a cambic horizon from 16 to 51 inches. The particle-size control section has an estimated moist bulk density of less than 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half iron of more than 1 percent.