LOCATION COYATA OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Humic Dystroxerepts
TYPICAL PEDON: Coyata gravelly loam, in a forested area. (Colors are for moist soil unless otherwise stated.)
O1--1 1/2 inches to 1; loose litter of undecomposed leaves, needles and tree limbs.
O2--1 inch to 0; partially decomposed moss, leaves, needles and
tree limbs.
A1--0 to 5 inches; dark reddish brown (5YR 3/3) gravelly loam, reddish brown (5YR 4/3) dry; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine to medium roots; many reddish brown and black concretions; 15 percent gravel; common white mycelia; slightly acid (pH 6.1); clear smooth boundary. (2 to 8 inches thick)
A2--5 to 9 inches; dark reddish brown (5YR 3/3) gravelly clay loam, reddish brown (5YR 4/3) dry; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine irregular pores; common reddish brown and black concretions; many white mycelia; 20 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (2 to 6 inches thick)
BA--9 to 13 inches; dark reddish brown (5YR 3/3) gravelly clay
loam, reddish brown (5YR 5/3) dry; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; common very fine to medium roots; many very fine pores; few reddish brown and black concretions; many white mycelia; 20 percent gravel; slightly acid (pH 6.1); clear wavy boundary. (0 to 10 inches thick)
Bw--13 to 20 inches; dark reddish brown (5YR 3/4) gravelly clay
loam, reddish brown (5YR 5/4) dry; weak medium and coarse subangular blocky structure; slightly hard, friable, sticky and plastic; few fine and medium roots; many very fine to medium pores; few thin clay films in some pores; 20 percent gravel and 5 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (5 to 10 inches thick)
BC--20 to 25 inches; dark reddish brown (5YR 3/4) very cobbly clay loam, reddish brown (5YR 5/4) dry; weak coarse subangular blocky structure; slightly hard, friable, sticky and slightly plastic; few fine and medium roots; common very fine to medium pores; few thin clay films in pores; 30 percent cobbles and 20 percent gravel; moderately acid (pH 5.9); gradual wavy boundary. (0 to 5 inches thick)
C--25 to 38 inches; yellowish red (5YR 4/6) extremely cobbly clay loam, light brown (7.5YR 6/4) dry; massive; hard, firm, slightly sticky and slightly plastic; common very fine to medium pores; 40 percent cobbles and 35 percent gravel; moderately acid (pH 6.0); abrupt wavy boundary. (0 to 15 inches thick)
R--38 inches; basalt.
TYPE LOCATION: Douglas County, Oregon; about 2 miles south of the confluence of Zinc Creek and South Umpqua River; SW1/4SW1/4 sec. 25, T. 29 S., R. 1 W.
RANGE IN CHARACTERISTICS: The soils are usually moist but are dry in the control section for 45 to 60 consecutive days during the 4 months following the summer solstice. The mean annual soil temperature is 47 to 52 degrees F. The soils are moist throughout the profiles during the winter. Depth to bedrock is 20 to 40 inches. Rock fragments in the control section commonly are 50 to 75 percent but in some pedons are as low as 35 percent. The control section averages about 25 to 35 percent clay.
The A and BA horizons have hue of 7.5YR or 5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. Rock fragments range from 15 to 25 percent gravel and 0 to 10 percent cobbles. It is moderately or slightly acid.
The Bw horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 3 through 6 moist and dry. Rock fragments range from 5 to 15 percent cobbles and 10 to 20 percent gravel. It is gravelly loam or gravelly clay loam. It is moderately or slightly acid.
The BC and C horizons has hue of 5YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 4 to 6 moist and dry. It is very cobbly loam or very cobbly or extremely cobbly clay loam with 20 to 40 percent cobbles and 20 to 35 percent gravel. It is strongly to slightly acid.
COMPETING SERIES: These are the Decy, Musty, Ovall and Tyson series. The Decy soils have hue of 10YR, have 10 to 25 percent clay in the particle-size control section, and are dry for over 60 consecutive days. Musty soils have hue of 10YR to 5Y and are dry for 60 to 90 consecutive days. Ovall soils have 10 to 15 percent clay in the particle-size control section. Tyson soils are dry for over 90 consecutive days and have hue of 10YR or 2.5Y.
GEOGRAPHIC SETTING: The Coyata soils are hillslopes and plateaus in mountainous uplands at elevations of 1,500 to 4,000 feet. Slopes range from 1 to 80 percent. The soils formed in colluvium and residuum weathered from basic igneous bedrock. They are in a subhumid climate with dry hot summers and warm wet winters. The mean annual precipitation is 35 to 60 inches. The mean annual temperature is 45 to 52 degrees F; the mean January temperature is 25 to 32 degrees F; and the mean July temperature is about 64 degrees F. The frost-free period is 100 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Dumont soil. Dumont soils have fine textured argillic horizons and are deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, and water supply. Native vegetation dominantly is Douglas fir, white fir, western hemlock and sugar pine with an understory of chinquapin, Pacific madrone, dogwood and snowberry.
DISTRIBUTION AND EXTENT: West side of central and southern Cascade Mountains, Oregon. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: South Umpqua Area, Douglas County, Oregon, 1974.
ADDITIONAL DATA: Partial characterization data reported for one pedon in the Soil Survey of the South Umpqua Area, Oregon, 1973.