LOCATION GRELL OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, magnesic, mesic Lithic Haploxerolls
TYPICAL PEDON: Grell very gravelly loam, rangeland. (Colors are for moist soil unless otherwise noted.)
A1--0 to 3 inches; black (10YR 2/1) very gravelly loam, dark gray (10YR 4/1) dry; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; 40 percent gravel, 10 percent cobbles; neutral (pH 6.8); clear smooth boundary. (2 to 4 inches thick)
A2--3 to 9 inches; very dark brown (10YR 2/2) very gravelly loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many very fine continuous pores; 40 percent gravel, 10 percent cobbles; neutral (pH 6.8); clear smooth boundary. (3 to 11 inches thick)
Bw--9 to 17 inches; dark brown (10YR 3/3) very gravelly loam, brown (10YR 4/3) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine continuous pores; 50 percent angular gravel and 10 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (4 to 12 inches thick)
R--17 inches; fractured serpentine bedrock, fractures 4 to 10 inches apart.
TYPE LOCATION: Grant County, Oregon; 3 miles southwest of John Day; 100 feet north of chrome prospect pit; 200 feet east and 1,100 feet north of the SW corner of section 3, T.14S., R.31E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 53 degrees F. The soils are usually moist but are dry in the control section for 80 to 100 consecutive days during the 4 month period following the summer solstice. Depth to the lithic contact and thickness of the mollic epipedon is 10 to 20 inches. Rock fragments range from 35 to 75 percent in the solum. The solum has more than 40 percent by weight of serpentine minerals.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 1 or 2 moist and dry.
The B horizon ranges narrowly around 3 moist and 5 dry and has chroma of 3 moist and 3 or 4 dry. It is loam and has 10 to 18 percent clay.
COMPETING SERIES: There are no competing series. The Bakeoven, Bodell, Lickskillet, Permanente, Plaskett, Swakane, Venator and Virgin Peak series are similar. All of these soils have less than 40 percent by weight serpentine minerals.
GEOGRAPHIC SETTING: Grell soils are on hills. The elevation is 3,000 to 5,000 feet. Slopes range from 7 to 50 percent. The soils formed in colluvium and residuum weathered mainly from serpentine and other ultramafic rocks. The climate is semiarid with a mean annual precipitation of 13 to 18 inches. The mean annual temperature is 45 to 50 degrees F.; the mean January temperature is about 30 degrees F.; and the mean July temperature is about 65 degrees F. The frost free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belshaw and Tub soils. Both are fine textured and lack a lithic contact at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Range. Present vegetation is bluebunch wheatgrass, Sandberg bluegrass, bitterbrush and gray rabbitbrush.
DISTRIBUTION AND EXTENT: East central Oregon; MLRA 10. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grant County, Oregon, 1975.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon 0 to 17 inches
Lithic contact at 17 inches
Xeric soil moisture regime