LOCATION JOHNTOM WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Haploxerolls
TYPICAL PEDON: Johntom stony ashy loam - on a 25 percent northwest-facing slope at 2,260 feet elevation. (Colors are for dry soil unless otherwise stated).
A--0 to 4 inches; brown (10YR 4/3) stony ashy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; 20 percent angular gravel, 5 percent cobbles, 5 percent stones; slightly acid (pH 6.2);clear wavy boundary.
AC--4 to 11 inches; brown (10YR 5/3) very gravelly ashy sandy loam, dark brown (10YR 3/3) most; weak very fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; 45 percent angular gravel, 10 percent cobbles; slightly acid (pH 6.2); clear wavy boundary (combined thickness of the A and AC horizons is 7 to 14 inches)
C--11 to 16 inches; pale brown (10YR 6/3) extremely gravelly coarse sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; 60 percent angular gravel, 10 percent cobbles; slightly acid (pH 6.4); abrupt wavy boundary. (0 to 8 inches thick)
R--16 inches; slightly weathered rhyodacite.
TYPE LOCATION: Okanogan County, Washington; about 6 miles north of the town of Nespelem; 1,700 feet east, 600 feet north of the southwest corner of sec. 19, T. 32 N., R. 31 E., W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 50 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 75 to 90 consecutive days following the summer solstice. Depth to a lithic contact ranges from 10 to 20 inches. The particle-size control section is 5 to 15 percent clay, 45 to 70 percent rock fragments by weighted average and has an estimated volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.10 to 0.25 percent and 15-bar water retention of 5 to 10 percent for air dried samples. Reaction is neutral or slightly acid throughout.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is 15 to 35 percent gravel, 5 to 20 percent cobbles and 0 to 10 percent stones.
The AC horizon is very gravelly ashy loam or extremely gravelly loam and is 30 to 60 percent gravel, 5 to 20 percent cobbles.
The C horizon has chroma of 2 or 3 dry or moist. It is very gravelly sandy loam, extremely gravelly sandy loam, or extremely gravelly coarse sandy loam. It is 40 to 70 percent gravel and 5 to 20 percent cobbles.
COMPETING SERIES: These are the Aldax, Bakeoven, Bodacious, Bodell, Couleedam, Hendap, Lickskillet, Limekiln, Plaskett, Rockly, and Venator series. Aldax soils are dry in all parts of the moisture control section for more than 90 consecutive days following the summer solstice and have a mollic epipedon that extends to the lithic contact. Bakeoven and Couleedam soils have an aridic moisture regime. Bakeoven, Bodacious, Bodell, Lickskillet, and Venator soils have 18 to 35 percent clay in the particle-size control section. In addition, Lickskillet soils have an aridic moisture regime. Hendap soils are calcareous throughout. Limekiln soils have a calcic horizon. Plaskett soils have a mean annual soil temperature of 55 to 58 degrees F. Rockly soils are 4 to 10 inches deep to a lithic contact.
GEOGRAPHIC SETTING: Johntom soils are on mountain ridges, shoulders, and upper backslopes. These soils formed in colluvium and residuum from rhyodacite and quartz latite, with a minor component of loess and volcanic ash. Slopes are 8 to 90 percent. Elevations range from 1,500 to 4,800 feet. The climate is characterized by warm, dry summers and cold, moist winters. The mean annual precipitation is 14 to 24 inches. The mean January temperature is about 25 degrees F, mean July temperature is about 69 degrees F, and the mean annual air temperature is 40 to 50 degrees F. The frost-free period is 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baldknob, Donavan, Inkler, Louiecreek, Northstar, Republic, Scoap, and Thout series. Baldknob soils are frigid and are on summits, shoulders, and backslopes of glacially scoured foothills and mountains. Inkler, Louiecreek, Republic, and Scoap soils are greater than 60 inches to bedrock. In addition, Inkler, Republic, and Scoap soils are frigid. Inkler soils are on foothills and mountains. Republic soils are on alluvial fans, terraces and footslopes and backslopes of mountains. Scoap soils are on uplands and mountainsides. Northstar and Thout are 20 to 40 inches deep to bedrock and are on glaciated mountainsides and ridgetops. Donavan soils are moderately deep to densic material Louiecreek and Northstar soils are on on toeslopes, footslopes, and backslopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Grazing, wildlife habitat, and watersheds are the principal uses. The native vegetation is bluebunch wheatgrass, Sandberg bluegrass, arrowleaf balsamroot, Wyeth eriogonum, stonecrop, common yarrow, Saskatoon serviceberry, and widely scattered ponderosa pine.
DISTRIBUTION AND EXTENT: North-central Washington; MLRA 43A. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Colville Indian Reservation, Ferry and Okanogan Counties, Washington, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 11 inches (A and AC horizon)
Vitrandic feature - the zone from 0 to 11 inches (A horizon)
Particle-size control section - the zone from 10 to 16 inches (part of the AC, and the C horizon).
Lithic contact at 16 inches