LOCATION APEX WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Andic Haploxerepts
TYPICAL PEDON: Apex ashy silt loam - on a 10 percent north facing slope at 2,240 feet elevation, under a Douglas-fir and ponderosa pine canopy. (Colors are for dry soil unless otherwise noted.)
0i--0 to 1 inch; needles, twigs, bark, and cones.
A--1 to 4 inches; brown (10YR 4/3) ashy silt loam, very dark grayish brown (10YR 3/2) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; many very fine and fine and few medium roots; 5 percent pebbles; NaF pH 9.8; slightly acid (pH 6.4); clear wavy boundary. (0 to 4 inches thick)
Bw1--4 to 9 inches; brown (10YR 4/3) ashy silt loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic, and weakly smeary; common very fine, fine and few medium roots; 5 percent pebbles; NaF pH 9.8; slightly acid (pH 6.2); clear wavy boundary. (2 to 6 inches thick)
Bw2--9 to 14 inches; yellowish brown (10YR 5/4) ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; common very fine, fine and few medium roots; 5 percent pebbles; NaF pH 9.8; slightly acid (pH 6.2); clear wavy boundary. (5 to 10 inches thick)
2Bw3--14 to 31 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine, medium and coarse roots; 20 percent pebbles; slightly acid (pH 6.2); gradual wavy boundary. (0 to 20 inches thick)
2Cd--31 to 60 inches; brown (10YR 5/3) dense glacial till that crushes to gravelly sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; few fine roots; 30 percent pebbles; slightly acid (pH 6.2).
TYPE LOCATION: Colville Indian Reservation; Ferry County, Washington. About 1 mile west of Simpson Lakes; 900 feet north and 100 feet east of the southwest corner sec. 33, T. 34 N., R. 36 E., W.M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is 44 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 following the summer solstice. The mantle of volcanic ash is 7 to 14 inches thick and contains 25 to 60 percent vitric volcanic ash in the fine-earth fraction. The ochric epipedon is 2 to 8 inches thick, but when it is 7 inches or more the solum thickness is 30 inches or more. Reaction is slightly acid or neutral throughout. Depth to densic material is 20 to 40 inches.
The A horizon has value of 3 through 7 dry, 3 through 5 moist, and chroma of 2 or 3 dry or moist.
The Bw horizon has value of 4 through 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry or moist. It is silt loam or loam. It is 0 to 10 percent pebbles.
The 2Bw horizon has value of 5 through 7 dry, 4 or 5 moist, and chroma of 3 or 4 dry or moist. It is silt loam, loam, sandy loam, gravelly loam, gravelly silt loam, or gravelly sandy loam. It has 5 to 35 percent coarse fragments, including 5 to 30 percent pebbles and 0 to 5 percent cobbles. The 2Bw horizon may be absent in some pedons.
The 2Cd horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 or 5 moist, and chroma of 2 through 4 dry or moist. It is gravelly loam, gravelly sandy loam, cobbly sandy loam, or stony sandy loam. It has 15 to 35 percent rock fragments, including 15 to 35 percent pebbles, 0 to 15 percent cobbles and stones. Moist bulk density is 1.70 to 2.00 with an RV of 1.85.
COMPETING SERIES: These are the Aits, Canteen, Centralpeak, Leadpoint, Moscow, Moso, and Waits series. Aits soils are dry for 45 to 60 consecutive days. Centralpeak, Leadpoint, and Moscow soils have a paralithic contact at a depth of 20 to 40 inches. Canteen soils are formed in granite residuum with a high content of quartz and feldspar minerals and are coarse sandy loam to loamy sand in the lower part of the particle-size control section. Waits soils are calcareous in the lower part of the particle-size control section. Moso soils are dry for 45 to 60 consecutive days.
GEOGRAPHIC SETTING: Apex soils are on toeslopes, footslopes, and backslopes of mountains and till plains. These soils formed in glacial till with a mantle of volcanic ash and loess. Slopes are 0 to 65 percent. Elevation ranges from 2,000 to 4,000 feet. The climate is characterized by warm, dry summers and cool, moist winters. Average annual precipitation is 15 to 22 inches. The mean January temperature is about 28 degrees F, mean July temperature is about 60 degrees, and mean annual temperature is 42 to 44 degrees F. Frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elbowlake, Kiehl, Martella, Mineral, Nevine, Newbell, Republic, Scrabblers, Stapaloop, and the competing Aits soils. Elbowlake and Nevine soils have a volcanic ash mantle more than 14 inches thick and are loamy-skeletal. Kiehl soils are sandy-skeletal. Martella soils have a fine- silty argillic horizon. Mineral soils are 20 to 40 inches deep to a lithic contact. Newbell soils are loamy-skeletal. Republic soils have a mollic epipedon 10 to 20 inches thick. Scrabblers soils are sandy. Stapaloop soils lack a mantle of volcanic ash.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate over slow permeability.
USE AND VEGETATION: Timber production, cropland, hay and pasture, livestock grazing, wildlife habitat and watershed. The native vegetation is Douglas-fir, ponderosa pine and western larch. Understory species include mallow ninebark, creambush oceanspray, common snowberry, pinegrass, pachystima, white spirea, and creeping Oregon-grape.
DISTRIBUTION AND EXTENT: Northeastern Washington. The series is of small 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 soil are an ochric epipedon from the mineral surface to 3 inches, a cambic horizon from 4 to 31 inches, and a mantle of volcanic ash from the mineral surface to 13 inches, with an estimated bulk density of 0.75 to 0.85 g/cc. The percent rock fragments in the 10- to 40-inch particle-size control section is 22 percent.