LOCATION DERR ORTentative Series
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Derr ashy loam - woodland. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 0.5 inch; pine needles and twigs.
A1--0.5 to 5 inches; very dark brown (10YR 2/2) ashy loam, brown (10YR 4/3) dry; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; 15 percent gravel size shale fragments; neutral (pH 6.6); gradual smooth boundary. (3 to 8 inches thick)
A2--5 to 11 inches; dark brown (10YR 3/3) ashy loam, brown (10YR 5/3) dry; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; many fine and very fine tubular pores; 15 percent gravel size shale fragments; slightly acid (pH 6.4); clear smooth boundary. (4 to 10 inches thick)
Bw1--11 to 22 inches; brown (10YR 4/3) light clay loam, brown (10YR 5/3) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; many fine and very fine tubular pores; few thin cutans; 15 percent gravel size shale fragments; slightly acid (pH 6.2); gradual smooth boundary. (8 to 14 inches thick)
Bw2--22 to 29 inches; brown (10YR 4/3) paragravelly clay loam, brown (10YR 5/3) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, sticky, plastic; many roots; common fine and medium tubular pores; few thin cutans; 20 percent gravel size shale fragments; slightly acid (pH 6.2); abrupt wavy boundary. (0 to 10 inches thick)
R--29 inches; fractured shale bedrock.
TYPE LOCATION: Wheeler County, Oregon, 1.6 miles east of Highway 19 on Straw Fork Road, then 1 mile south on logging road, south side of road, northeast 1/4, southwest 1/4, sec. 17, T. 7 S., R. 22 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 42 to 47 degrees F, and the mean summer soil temperature from 49 to 56 degrees F, under an O horizon. These soils are usually moist but are dry throughout between 4 and 12 inches more than 60 consecutive days during the summer months. The solum ranges from slightly acid to neutral. Depth to lithic contact and shale bedrock ranges from 20 to 40 inches. The solum commonly is in 10YR hue but ranges to 7.5YR. Coarse fragments in the solum are mainly gravel size shale and range from 10 to 35 percent.
The A horizon has values of 2 or 3 moist and 4 or 5 dry and chromas of 2 or 3. It is ashy loam or shaly ashy loam. Thickness of the A horizons ranges from 7 to 18 inches but is not less than 1/3 the thickness of the solum when the solum is 20 to 30 inches thick and is at least 10 inches thick when the solum is 30 to 40 inches thick.
The Bw horizon has values of 4 moist, 5 or 6 dry, and chromas of 3 or 4 moist and dry. It is clay loam with 27 to 35 percent clay and more than 15 percent coarser than very fine sand.
COMPETING SERIES: These are the Buford, Hall Ranch, Highvalley, Kahler, Minam, and Myzel series. The Buford soils are deep to a lithic contact. The Hall Ranch soils are moderately deep to a paralithic contact. The Highvalley, Kahler, Minam, and Myzel soils are very deep.
GEOGRAPHIC SETTING: Derr soils are on gently sloping to very steep uplands at elevations ranging from 3,300 to 5,000 feet. They have formed from moderately fine textured colluvium and residuum weathered shale bedrock. The climate is subhumid with a mean annual precipitation of 17 to 24 inches. The mean annual temperature is about 43 degrees F, the mean July temperature is about 63 degrees F, and the mean January temperature is about 25 degrees F. The frost-free period ranges from less than 30 days to about 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Hankins and the competing Klicker and Hall Ranch soils. Hankins soils have clayey argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained. Slow to moderate runoff; moderately slow permeability.
USE AND VEGETATION: Timber production and grazing. The vegetation consists of ponderosa pine and Douglas-fir with an understory of elksedge and pinegrass and some Idaho fescue and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Principally in Wheeler County, possibly in Crook County, Oregon. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Wheeler County, Oregon, 1971.
REMARKS: Base saturation is assumed to be less than 75 percent in some part in the upper 30 inches. This draft reflects a classification change from fine-loamy, mixed, frigid Ultic Haploxerolls to fine-loamy, isotic, frigid Vitrandic Haploxerolls.