LOCATION NATI WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Typic Haplorthods
TYPICAL PEDON: Nati loam - on 17 percent northwest facing slope under a coniferous forest canopy of Douglas-fir at 1,500 feet elevation. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures)
Oi--3 1/2 to 3 inches; undecomposed needles, leaves, and twigs.
Oa--3 inches to 0; decomposed forest litter; many very fine and fine roots.
A--0 to 8 inches; dark brown (10YR 3/3) loam, yellowish brown (10YR 5/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic, weakly smeary; common very fine and fine, many medium, and common coarse roots; many fine irregular pores; 5 percent weathered pebbles; NaF pH 10.l; strongly acid (pH 5.1); abrupt smooth boundary. (3 to 10 inches thick)
Bs--8 to 16 inches; dark yellowish brown (10YR 4/4) loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine, fine, and medium roots; many fine irregular pores; 30 percent weathered pebbles and 5 percent hard rounded pebbles; NaF pH 10.6; strongly acid (pH 5.2); abrupt smooth boundary. (6 to 16 inches thick)
BC--16 to 31 inches; brownish yellow (10YR 6/6) fine sandy loam, pale yellow (2.5Y 7/4) dry; massive; soft, very friable, nonsticky, nonplastic, weakly smeary; few fine medium and coarse roots; many fine irregular pores; 35 percent weathered pebbles; NaF pH 11.0; strongly acid (pH 5.4); abrupt wavy boundary. (0 to 15 inches thick)
2Cr--31 inches; sandstone.
TYPE LOCATION: Whatcom County, Washington, about 6 miles southeast of Bellingham; 400 feet north and 2,000 feet east of the southwest corner of sec. 12, T. 37 N., R. 4 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 48 degrees to 51 degrees F. Depth to a paralithic contact with sandstone and thickness of volcanic ash influence is 20 to 40 inches. The soil moisture control section is dry in all parts for 60 to 75 consecutive days within the four months that follow the summer solstice in 6 or more years out of 10. By weighted average, the control section has 5 to 20 percent hard rounded pebbles, 20 to 40 percent weathered pebbles, and 0 to 15 percent weathered cobbles. Reaction is strongly acid or moderately acid throughout.
The A horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 2 through 6 moist, 4 through 6 dry. It has 0 to 15 percent hard rounded pebbles, 10 to 25 percent weathered pebbles, and 0 to 15 percent weathered cobbles.
The Bs horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 4 through 6 moist and dry. It has 5 to 15 percent hard rounded pebbles, 15 to 30 percent weathered pebbles, and 0 to 15 percent weathered cobbles. It is loam or sandy loam.
The BC horizon has hue of 7.5YR through 2.5Y, value of 4 through 6 moist, 6 or 7 dry, and chroma of 4 through 6 dry. It has 5 to 25 percent hard rounded pebbles, 15 to 45 percent weathered pebbles, and 0 to 20 percent weathered cobbles and stones. It is loam, sandy loam, fine sandy loam, or gravelly loam. Some pedons have a C horizon and lack a BC horizon.
COMPETING SERIES: These are the Chuckanut, Kickerville, Sehome, and Squalicum series and the similar Cathcart, Cathlamet, Comar, Giles, Nevat, Pastik, Pronto, Sadie, and Sulsavar series. All of these soils are more than 40 inches deep except Sadie and Sehome. Sadie and Sehome soils are 20 to 40 inches deep to a paralithic contact with dense compact glacial till.
GEOGRAPHIC SETTING: Nati soils are on colluvial mountain backslopes and plateaus at elevations of 100 to 1,600 feet. Slopes are 5 to 60 percent. The soils formed in colluvium and slope alluvium from sandstone and siltstone with an admixture of volcanic ash and glacial till. Nati soils are in a marine climate with warm, dry summers and cool, moist winters. Snow cover is intermittent. Average annual precipitation is 35 to 50 inches. Mean January temperature is about 36 degrees F; mean July temperature is about 62 degrees F. Mean annual temperature is about 48 degrees F. The frost-free season is 140 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Cathcart Sehome and, Squalicum soils and the Revel soils. Revel soils are frigid.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, homesites, recreation, and wildlife habitat. Vegetation is Douglas-fir, western hemlock, western redcedar, and red alder with an undergrowth of western swordfern, salal, red huckleberry, and western brackenfern.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains is northwestern Washington. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Whatcom County, 1983.
REMARKS: This draft reflects a change in classification from medial, mesic Andic Xerochrepts to coarse-loamy, mixed, mesic Typic Haplorthods. Diagnostic horizons and features recognized in this soil are an ochric epipedon from the surface to 8 inches, a spodic horizon from 8 to 16 inches, and a paralithic contact at 31 inches. The spodic horizon does not meet spodic chemical criteria, but does meet micro morphological criteria, i.e. cracked coatings and silt-sized and larger pellets.