LOCATION TORBOY WAEstablished Series
TAXONOMIC CLASS: Sandy, isotic, frigid Vitrandic Haploxerepts
TYPICAL PEDON: Torboy ashy sandy loam, woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed needles, twigs.
C--1 to 1.25 inch; white (10YR 8/1) ashy sandy loam, gray (10YR 6/1) moist; weak coarse granular structure; soft, very friable, nonsticky, nonplastic; many roots; neutral (pH 6.6); abrupt smooth boundary. (0 to 1/2 inch thick)
Bw1--1.25 to 7 inches; pale brown (10YR 6/3) ashy sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; many roots; 10 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (3 to 8 inches thick)
Bw2--7 to 18 inches; pale brown (10YR 6/3) ashy sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; common roots; few fine pores; 10 percent fine gravel; slightly acid (pH 6.5); abrupt wavy boundary. (6 to 15 inches thick)
2C1--18 to 25 inches; light brownish gray (10YR 6/2) gravelly loamy sand, dark grayish brown (10YR 4/2) moist; many medium distinct mottles of dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky, nonplastic; common roots; 25 percent gravel; slightly acid (pH 6.5); abrupt smooth boundary. (4 to 10 inches thick)
2C2--25 to 33 inches; multicolored very gravelly sand; single grained; loose, nonsticky, nonplastic; few roots; 35 percent gravel, 10 percent cobbles; neutral (pH 6.7); gradual wavy boundary. (8 to 14 inches thick)
2C3--33 to 61 inches; multicolored gravelly sand; single grained; loose, nonsticky, nonplastic; few roots; 25 percent gravel; neutral (pH 6.8).
TYPE LOCATION: Ferry County, Washington; 50 feet south of old west fork road and 0.2 miles northeast of its junction with the west fork of Trout Creek Road; 2,050 feet east and 1,450 feet south of northwest corner of section 35, T.38N., R.32E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is 43 to 47 degrees F. These soils are usually moist but are dry in all parts between depths of 8 and 24 inches for 60 to 75 consecutive days. Solum thickness ranges from 14 to 20 inches. The upper 9 to 18 inches has an estimated moist bulk density of 1.20 to 1.45 g/cc, volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.4 to 1.0 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. The control section is 10 to 35 percent coarse fragments.
The C (when present) horizon has value of 7 or 8 dry, 5 or 6 moist, and chroma of 1 or 2 dry or moist. This is a thin layer of Mt. St. Helens 'T' and 'W' volcanic ash and may be absent in some pedons. When the Mt. St. Helens ash is absent, the A horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 to 4 dry or moist. It is 0 to 10 percent gravel.
The 2Bw horizon has value of 5 to 7 dry, 3 through 5 moist, and chroma of 2 to 4 dry or moist. It is sandy loam, fine sandy loam, gravelly fine sandy loam or gravelly sandy loam. It is 0 to 20 percent gravel and 0 to 5 percent cobbles. Reaction is slightly acid or neutral.
The 2C horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry, 4 or 5 moist, and chroma of 1 to 4 dry or moist, or it is multicolored. It is loamy fine sand, loamy sand, fine sand or sand and is gravelly or very gravelly. It has 5 to 45 percent gravel and 0 to 10 percent cobbles. Reaction is slightly acid or neutral.
COMPETING SERIES: This is the Kaniksu series. The Kaniksu soils have E&Bt horizons.
GEOGRAPHIC SETTING: Torboy soils are on terraces and terrace escarpments and on toeslopes, footslopes, and backslopes of mountains at elevations of 2,800 to 5,000 feet. Slopes are 0 to 65 percent. These soils are in a climate with warm, dry summers and cool, moist winters. The average annual precipitation is about 15 to 30 inches. The average annual temperature is about 40 to 45 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goddard, Merkel, Nevine, Scrabblers, Stapaloop, Wapal, and the competing Karamin series. Goddard soils have a mantle of volcanic ash 7 to 14 inches thick, are sandy-skeletal, and are on similar landscapes as Torboy soils. Merkel soils are loamy-skeletal and are on mountains. Nevine soils have a mantle of volcanic ash 14 to 30 inches thick and are on moraines, foothills and mountains. Scrabblers soils hae a mantle of volcanic ash 7 to 14 inches thick and are on similar landscapes as Torboy soils. Stapaloop soils are coarse-loamy. Wapal soils are sandy-skeletal. Scrabblers and Wapal soils are on similar landscapes as Torboy soils.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately rapid permeability in the upper part and very rapid in the lower part.
USE AND VEGETATION: Used for timber production, grazing, cropland, and wildlife habitat. Vegetation is Douglas-fir, ponderosa pine, western larch, and lodgepole pine, with an understory of pachystima, kinnikinnick, common snowberry, silky lupine, and pinegrass.
DISTRIBUTION AND EXTENT: Northeastern Washington. MLRA 43A. Torboy series is of small extent.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ferry County (North Ferry Area), Washington, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are a thin ochric epipedon 1/4 inch thick formed in Mt. St. Helens 'T' or 'W' volcanic ash, a cambic horizon from 1.25 to 18 inches. Though the coarse-loamy B extends to 17 inches, it averages more than 50 percent fine or coarser sand and does not meet contrasting particle-size criteria. The description reflects a change in classification due to Andisols, from sandy, mixed, frigid Typic Xerochrepts to sandy, mixed, frigid Vitrandic Xerochrepts.