LOCATION PETTIJOHN WA

Established Series
Rev. BJD/RJR/TLA
01/2011

PETTIJOHN SERIES

The Pettijohn series consists of very deep, well drained soils formed in volcanic ash over granitic colluvium. These soils are on backslopes of mountains. Slopes are 35 to 65 percent. The mean annual precipitation is about 21 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Typic Vitrixerands

TYPICAL PEDON: Pettijohn stony ashy fine sandy loam, forestland on a southeast facing 60 percent slope, at 4,700 feet elevation under a Douglas-fir canopy. (When described on June 4, 1992 the soil was moist through most of the moisture control section. Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)

Oe--0 to 2 inches; moderately decomposed needles, leaves and twigs; abrupt smooth boundary. (1 to 4 inches thick)

A--2 to 6 inches; pale brown (10YR 6/3) stony ashy fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic and weakly smeary; many very fine and fine, and common medium roots; many very fine and fine irregular pores; 5 percent gravel, 10 percent cobbles, and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (3 to 6 inches thick)

Bw1--6 to 26 inches; pale brown (10YR 6/3) very cobbly ashy fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic and weakly smeary; many very fine and fine, common coarse, and few medium roots; many very fine and fine irregular pores; 10 percent gravel, 30 percent cobbles and 10 percent stones; slightly acid (pH 6.4); gradual wavy boundary. (10 to 25 inches thick)

Bw2--26 to 44 inches; very pale brown (10YR 7/4) very stony ashy fine sandy loam, dark yellowish brown (10YR 4/6) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic and weakly smeary; common very fine, fine and coarse, and few medium roots; many fine irregular pores; 15 percent gravel, 25 percent cobbles and 15 percent stones; slightly acid (pH 6.2); gradual wavy boundary. (10 to 20 inches thick)

2C--44 to 62 inches; light yellowish brown (2.5Y 6/3) very gravelly sandy loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine, fine and medium roots; common fine irregular pores; 40 percent gravel, 5 percent cobbles, and 2 percent stones; slightly acid (pH 6.4).

TYPE LOCATION: Okanogan County, Washington; about 1 mile west of Bonaparte Lake, about 1,300 feet north and 2,600 feet east of the southwest corner of section 8, T. 38N., R. 30E., WM. (Latitude 48 degrees, 48 minutes, 08 seconds N., Longitude 119 degrees, 03 minutes, 59 seconds W.)

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 47 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 60 to 75 consecutive days following the summer solstice. Thickness of the volcanic ash mantle is 30 to 45 inches and has an estimated moist bulk density of 0.85 to 1.00 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent, and 15-bar water retention of 5 to 12 percent for air dried samples. The particle-size control section has 35 to 60 percent rock fragments. Reaction is slightly acid to neutral throughout.

The A horizon has value of 4 to 6 dry, 3 or 4 moist and chroma of 3 or 4 dry or moist.

The Bw horizons have value of 5 to 7 dry, 4 or 5 moist and chroma of 3 to 6 dry or moist. It is very cobbly ashy fine sandy loam or very stony ashy fine sandy loam. It has 35 to 60 percent rock fragments with 10 to 20 percent gravel, 10 to 35 percent cobbles, and 2 to 15 percent stones.

The 2C horizon has hue of 2.5Y or 10YR, value of 6 or 7 dry, 4 to 6 moist and chroma of 3 or 4 dry or moist. It is very gravelly sandy loam or very cobbly sandy loam. It has 35 to 60 percent rock fragments with 20 to 40 percent gravel, 5 to 20 percent cobbles and 2 to 10 percent stones.

COMPETING SERIES: These are the Doe, Grenet, Kusu, Natkim, Roundknoll, Stien, Stices, Twelvemile and Yallani series. The Doe soils are loamy coarse sand in the 2C horizon and have 20 to 35 inches of volcanic ash influence. The Grenet soils is 20 to 40 inches to paralithic contact. The Kusu soils is 40 to 60 inches to lithic contact. Twelvemile soils have 7 to 18 percent clay in the particle-size control section and have a Bt horizon. Stices soils are dry for 45 to 60 consecutive days after the summer solstice. The Yallani soils average 18 to 24 percent clay in the particle-size control section. Natkim soils are dry 45 to 60 consecutive days. Roundknoll soils have a calcic horizon at 10 to 20 inches. Stien soils have an ash mantle 14 to 20 inches thick with the lower material being sandy-skeletal.

GEOGRAPHIC SETTING: The Pettijohn soils are on backslopes of mountains at elevation of 2,600 to 5,900 feet. Slopes are 35 to 65 percent. These soils formed in a mixture of volcanic ash and granitic colluvium. The climate is characterized by warm, dry summers and cool, wet winters. The mean annual precipitation is 18 to 30 inches. The mean January temperature is 22 to 26 degrees F., the mean July temperature is 62 to 67 degrees F., and the mean annual air temperature is 40 to 46 degrees F. The frost-free season is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nevine, Myerscreek, and Resner soils. Nevine soils are on backslopes of mountains and have a 2Cd horizon. Myerscreek and Resner soils are cryic. Myerscreek soils are on backslopes of mountains and have 7 to 14 inches of volcanic ash over loamy-skeletal glacial till. Resner soils are on outwash terraces and mountain footslopes, and are ashy over sandy or sandy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained, rapid and very rapid runoff, moderate permeability.

USE AND VEGETATION: Timber production, wildlife habitat and watershed. Native vegetation is Douglas-fir, western larch, ponderosa pine, pinegrass, pachystima, black mountain huckleberry, shinyleaf spirea, kinnikinnick, and mallow ninebark.

DISTRIBUTION AND EXTENT: Okanogan County, Washington. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Okanogan County, Washington, Okanogan National Forest, 2005.

REMARKS: Diagnostic horizons and features recognized in this soil are:
Ochric epipedon
Cambic horizon from 6 to 44 inches.
Andic soil property requirements are met from 2 to 44 inches.
The particle-size control section averages 53 percent rock fragments.
Soils in which the ash mantle is less than 40 inches thick would classify as ashy-skeletal over loamy-skeletal.

ADDITIONAL DATA: Partial data available for this pedon; 94P2213-94P2214.

National Cooperative Soil Survey
U.S.A.