LOCATION EGYPTCREEK OR
Established Series
Rev: JAP/TDT
03/2013
EGYPTCREEK SERIES
The Egyptcreek series consists of moderately deep, well drained soils that formed in colluvium from welded tuff. Egyptcreek soils are on hillsides, canyonsides, and escarpments. Slopes are 20 to 60 percent. Mean annual precipitation is about 17 inches and the mean annual air temperature is about 42 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Egyptcreek very gravelly loam on a 22 percent north-facing canyon sideslope, at 4,900 feet elevation - woodland. (Colors are for dry soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed needles and twigs; abrupt smooth boundary. (0.5 to 1.5 inches thick)
A1--0 to 2 inches; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, moderately sticky and moderately plastic; common very fine and fine roots; few fine irregular pores; 30 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear smooth boundary.
A2--2 to 8 inches; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few fine, medium and coarse roots; few fine irregular discontinuous pores; 35 percent gravel and 5 percent cobbles; neutral (pH 6.6); gradual wavy boundary. (Combined thickness of the A horizon is 7 to 14 inches)
Bw1--8 to 18 inches; yellowish brown (10YR 5/4) very gravelly loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine medium and coarse roots; few fine irregular discontinuous pores; 45 percent gravel and 10 percent cobbles; neutral (pH 6.6); gradual wavy boundary.
Bw2--18 to 24 inches; yellowish brown (10YR 5/4) extremely cobbly loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine, medium and coarse roots; few fine irregular discontinuous pores; 20 percent gravel, 40 percent cobbles and 5 percent stones; neutral (pH 6.6); abrupt irregular boundary. (Combined thickness of the Bw horizon 10 to 26 inches)
R--24 inches; fractured welded tuff.
TYPE LOCATION: Harney County, Oregon; about 660 feet south and 3,300 feet east of the northwest corner section 29, T. 21 S., R 27 E. (Latitude 43 degrees, 43 minutes, 37 seconds N, Longitude 119 degrees, 30 minutes, 9 seconds W. NAD 1927)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 47 degrees F. The soil moisture control section is dry for 75 to 90 consecutive days. Base saturation (sum) is 60 to 75 percent in the surface and upper part of the subsoil and can range to over 75 percent in the lower part of the subsoil. The mollic epipedon is 7 to 14 inches thick. The solum and depth to a lithic contact is 20 to 36 inches. The particle size control section averages 35 to 60 percent rock fragments and 20 to 27 percent clay. Reaction is slightly acid to neutral. A thin 1 to 3 inch thick C horizon is present in some pedons above the bedrock.
The A horizon has value of 4 or 5 dry, 3 moist, and chroma of 2 or 3 moist or dry. The darker value and chroma occur in the upper part. It contains 35 to 60 percent rock fragments consisting of gravel, cobbles and stones. Glass content is estimated to be 5 to 30 percent. Acid oxalate aluminum plus one-half the acid oxalate iron is 0.4 to 0.8.
The B horizon has value of 5 or 6 dry, 3 moist, and chroma of 3 or 4 moist or dry. It contains 35 to 70 percent rock fragments consisting of gravel and cobbles.
COMPETING SERIES: There are the
Bearspring,
Dogtown,
Frint,
Hogranch,
Mineral,
Peahke,
Scoap,
Wellscreek, and the tentative
Cassal,
Midpeak,
Pelican,
Shalrock and Yellwcreek series. All of these soils are over 40 inches deep except for the Frint, Mineral, Peahke, midpeak and Shalrock series. Frint and Scoap soils have mollic epipedons over 20 inches thick. Mineral soils have 7 to 12 percent clay in the particle-size control section. Midpeak and Shalrock soils are dry for 60 to 75 consecutive days and have 5 to 15 percent clay in the control section.
GEOGRAPHIC SETTING: Egyptcreek soils are hillsides, canyonsides, and escarpments. The soils formed in loess and colluvium from welded tuff. Slopes are 20 to 60 percent. Elevations are 4,200 to 5,200 feet. The climate is characterized by cold, wet winters, and hot, dry summers. The mean annual precipitation is 16 to 18 inches. The mean annual air temperature is 40 to 43 degrees F. The frost free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Anatone and
Lambring soils. Anatone soils are shallow to bedrock and are on south and west facing canyonsides and hillsides. Lambring soils are deep to bedrock and have a mollic epipedon greater than 20 inches thick and are on canyonsides, hillsides, and escarpments.
DRAINAGE AND PERMEABILITY: Well drained; moderate to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for livestock grazing, and woodland. The native vegetation is ponderosa pine, western juniper, mountain big sagebrush, antelope bitterbrush, Idaho fescue, bluebunch wheatgrass, and Sandberg's bluegrass.
DISTRIBUTION AND EXTENT: Southeastern Oregon, MLRA 10. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Harney County, Oregon 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 8 inches (A1, A2 horizons)
Cambic horizon - 8 to 24 inches (Bw1, Bw2 horizons)
Particle size control section - 10 to 24 inches (Bw1, Bw2 horizons)
Base saturation - Base saturation is less than 75 percent in some horizon between 10 and 24 inches, estimated (ultic).
National Cooperative Soil Survey
U.S.A.