LOCATION ONTRAIL WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerepts
TYPICAL PEDON: Ontrail gravelly ashy sandy loam, on a northeast facing 36 percent slope at an elevation of 2,680 feet in a Douglas-fir and ponderosa pine forest. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles and twigs; abrupt smooth boundary. (1 to 2 inches thick)
A--1 to 5 inches; brown (7.5YR 4/2) gravelly ashy sandy loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and few medium roots; common very fine and fine irregular pores; 15 percent pebbles; neutral (pH 6.6); clear smooth boundary. (4 to 8 inches thick)
Bw--5 to 17 inches; brown (7.5YR 5/3) gravelly ashy sandy loam, brown (7.5YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine, and few medium roots; common very fine and fine irregular pores; 20 percent pebbles; slightly acid (pH 6.4); clear wavy boundary. (6 to 12 inches thick)
2C1--17 to 33 inches; reddish brown (5YR 5/3) very gravelly sandy loam, reddish brown (5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few fine irregular pores; 35 percent pebbles and 5 percent cobbles; slightly acid (pH 6.4); gradual wavy boundary. (9 to 20 inches thick)
2C2--33 to 61 inches; reddish brown (5YR 5/3) very gravelly sandy loam, reddish brown (5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; few fine irregular pores; 45 percent pebbles and 5 percent cobbles; slightly acid (pH 6.3).
TYPE LOCATION: Okanogan County, Washington; about 1.5 miles southeast of Mazama, Wa., 2,100 feet west and 2,700 feet south of the northeast corner of section 36, T. 36 N., R. 19 E. (Latitude 48 degrees 34' 38"N., Longitude 120 degrees 24' 38"W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 60 to 75 days following the summer solstice. These soils do not meet the organic carbon content of 0.6 or more for mollic epipedons. Thickness of the volcanic ash influence is 10 to 20 inches, and has an estimated moist bulk density of 1.10 to 1.40 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 particle-size control section averages 35 to 60 percent rock fragments and 5 to 12 percent clay. Reaction is slightly acid to neutral throughout.
The A horizon has hues of 5YR and 7.5YR, and chromas of 2 or 3 dry.
The Bw horizon has hues of 5YR and 7.5YR, values of 5 or 6 dry, and chromas of 2 or 3 dry or moist. It is gravelly ashy sandy loam or very gravelly ashy sandy loam. It has 15 to 35 percent gravels.
The 2C horizon has value of 3 or 4 moist, and chromas of 2 or 3 dry or moist. It is very gravelly sandy loam or very cobbly sandy loam. It has 30 to 45 percent pebbles and 5 to 20 percent cobbles.
COMPETING SERIES: These are the Brevco, Coxit, Elkrock (T), Highhorn, Huntrock, Jimbluff, Kamela, Longort, Merkel, Redpeak, and Thout series. Brevco, Kamela, Redpeak, Santop and Thout soils are moderately deep to a lithic contact. Coxit soils lack red hues and have 8 to 18 percent clay. Elkrock soils have a mean annual soil temperature of 45 to 47 degrees F. and 60 to 80 percent rock fragments in the C horizon. Highhorn soils have 27 to 35 percent clay in the particle-size control section and bedrock at a depth of 40 to 60 inches. Huntrock soils have 27 to 35 percent clay and 60 to 80 percent rock fragments in the particle-size control section. Jimbluff soils lack red hues and have extremely gravelly loamy sand 3C horizons. Longort soils lack red hues and have Cd horizons. Merkel soils lack red hues and have Cd horizon.
GEOGRAPHIC SETTING: Ontrail soils are on backslopes of mountains. Elevations range from 2,200 to 3,800 feet. Slopes are 35 to 65 percent. These soils formed in colluvium and till from sedimentary and volcanic rock sources of the Ventura Member of the Midnight Peak Formation, with a component of volcanic ash in the upper part. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation ranges from 20 to 24 inches. The average January temperature ranges from 22 to 26 degrees F.; the average July temperature ranges from 62 to 67 degrees F.; and the average annual air temperature ranges from 40 to 44 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buckrock, Jimbluff, Redpeak (T), and Veridge (T) soils. Buckrock soils are on open shoulders and ridges and are mesic. Jimbluff soils are on footslopes and alluvial fans. Redpeak soils are on backslopes and shoulders and have bedrock at 20 to 40 inches. Veridge soils are on northerly aspects and have an andic volcanic ash mantle 7 to 14 inches thick.
DRAINAGE AND PERMEABILITY: Well drained, rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat, watershed, and recreation. Native vegetation is Douglas-fir and ponderosa pine with an understory of pinegrass, shinyleaf spirea, Saskatoon serviceberry, and mountain snowberry.
DISTRIBUTION AND EXTENT: Northcentral Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan National Forest, Okanogan County, Washington, 2005.
REMARKS: Diagnostic horizons and features in this pedon include: Ochric epipedon - 0 to 4 inches
Cambic horizon - 4 to 16 inches
PSCS - zone from 10 to 40 inches (part of the Bw, 2C1 and part of the 2C2 horizon.
Vitrandic properties from 0 to 16 inches.