LOCATION NEVAT WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitrandic Haploxerepts
TYPICAL PEDON: Nevat ashy sand - forested. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 2 inches; slightly decomposed needles and twigs; abrupt smooth boundary. (1 to 2 inches thick)
A--2 to 6 inches; very dark gray (10YR 3/1) ashy sand, gray (10YR 5/1) dry; single grain; loose; many very fine, fine and medium roots; many very fine interstitial pores; neutral (pH 6.8); clear wavy boundary. (1 to 5 inches thick)
AC--6 to 10 inches; grayish brown (10YR 5/2) ashy sand, very pale brown (10YR 7/3) dry; single grain; loose; many very fine, fine and medium roots; many very fine interstitial pores; neutral (pH 6.8); abrupt smooth boundary. (2 to 9 inches thick)
2Ab--10 to 13 inches; dark brown (10YR 3/3) gravelly sandy loam, brown (10YR 5/3) dry, common medium faint brown (10YR 5/3) redox concentrations, not visible dry; weak medium and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine to coarse roots; common very fine tubular and many very fine interstitial pores; 20 percent gravel; slightly acid (pH 6.4); clear wavy boundary. ( 2 to 7 inches thick)
2Bwb--13 to 43 inches; dark yellowish brown (10YR 4/4) gravelly sandy loam, yellowish brown (10YR 5/4) dry; weak medium and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine to coarse roots; common very fine tubular and many very fine interstitial pores; 20 percent gravel; neutral (pH 6.6); abrupt smooth boundary. (20 to 45 inches thick)
2R--43 inches; andesite.
TYPE LOCATION: Lewis County, Washington; one mile north of Packwood; l,900 feet east and l,700 feet north of southeast corner of sec. l5, T. l2 N., R. 9 E.
RANGE IN CHARACTERISTICS: The volcanic ash layer is 7 to l3 inches thick. Mean annual soil temperature ranges from 47 to 5l F. Nevat soils are usually moist but are dry in all parts for 45 to 60 consecutive days between depths of 8 to 24 inches. Depth to bedrock ranges from 40 to 60 inches. These soils are slightly acid or neutral throughout. The control section at depths between l0 and 40 inches averages l5 to 30 percent rock fragments. Hue is l0YR or 7.5YR.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of l or 2 moist and dry.
The 2Ab horizon has chroma of 2 or 3 moist or dry and is gravelly sandy loam or gravelly fine sandy loam.
The 2Bwb has value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 or 4 moist and dry. It is gravelly sandy loam or gravelly fine sandy loam.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Nevat soils are on mountain footslopes and have gradients of 2 to 90 percent. They formed from mixed colluvium with a mantle of volcanic ash. Elevations are 800 to l,800 feet. The soils are in a marine type climate with mean annual precipitation of 50 to 70 inches occurring mostly as rain during the winter. Mean January temperature is about 36 degrees F.; mean July temperature is about 63 degrees F.; and the mean annual temperature is about 48 degrees F. The frost-free season is l25 to l75 days. The growing season (28 degrees F.) is l70 to l90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cispus, Cotteral, and Netrac soils. Cispus and Cotteral soils have more than 60 percent vitric volcanic ash, cinders, or other pyroclastic material to a depth of 60 cm or more. Netrac soils have more than 35 percent rock fragments by volume in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; rapid permeability in the A and AC horizons and moderate below.
USE AND VEGETATION: Forestland.
DISTRIBUTION AND EXTENT: Eastern Lewis County, Washington; MLRA 2. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lewis County, Washington, l976.
REMARKS: Diagnostic horizons and other features:
Andic soil properties from 2 to 10 inches
Ochric epipedon
Cambic horizon from 11 to 41 inches