LOCATION FORDICE OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Fordice very cobbly loam - on a 2 percent slope in an improved pasture. (When described, the soils were moist. Colors are for moist soil unless otherwise noted.)
A1--0 to 6 inches; dark brown (7.5YR 3/2) very cobbly loam, brown (10YR 5/3) dry; strong fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine continuous interstitial and tubular pores; 20 percent cobbles, 25 percent gravel; strongly acid; clear smooth boundary. (3 to 8 inches thick)
A2--6 to 13 inches; dark brown (7.5YR 3/2) very cobbly loam, brown (10YR 5/3) dry; moderate fine and medium granular and subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; moderate very fine, fine and medium roots; many very fine and fine continuous interstitial and tubular pores; 30 percent cobbles, 20 percent gravel; strongly acid; clear smooth boundary. (3 to 8 inches thick)
BAt--13 to 19 inches; dark brown (7.5YR 3/4) extremely cobbly loam; brown (7.5YR 5/4) dry; moderate fine and medium subangular blocky structure; hard, firm, sticky and slightly plastic; common very fine and fine roots; many very fine and fine continuous interstitial and tubular pores; few distinct strong brown (7.5YR 4/6) clay films on faces of peds and lining pores; 40 percent gravel, 20 percent cobbles; moderately acid; clear smooth boundary. (3 to 8 inches thick)
Bt1--19 to 35 inches; dark brown (7.5YR 4/4) extremely gravelly clay loam, strong brown (7.5YR 5/6) dry; weak medium and coarse subangular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots; many very fine and fine continuous tubular pores; many distinct strong brown (7.5YR 4/6) clay films on faces of peds, lining pores and coating cobbles and gravel; common medium distinct black (10YR 2/1) stains on faces of peds; 50 percent gravel, 20 percent cobbles; moderately acid; clear smooth boundary. (10 to 18 inches thick)
Bt2--35 to 56 inches; dark brown (7.5YR 4/4) extremely cobbly clay loam, strong brown (7.5YR 5/6) dry; weak fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots; many fine and medium continuous tubular pores; many distinct strong brown (7.5YR 4/6) clay films on faces of peds, lining pores and coating cobbles and gravel; many medium distinct black (10YR 2/1) stains on faces of peds and coating gravel and cobbles; 40 percent gravel, 35 percent cobbles; moderately acid; clear smooth boundary. (12 to 23 inches thick)
BCt--56 to 63 inches; dark brown (7.5YR 4/4) extremely cobbly loam, strong brown (7.5YR 5/6) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; many fine and medium continuous tubular pores; many distinct strong brown (7.5YR 4/6) clay films on faces of peds, lining pores and coating cobbles and gravel; many medium distinct black (10YR 2/1) stains on faces of peds and coating cobbles and pebbles; 40 percent cobbles, 30 percent gravel; moderately acid.
TYPE LOCATION: Douglas County, Oregon; about 2 miles west of Glide, near State Highway 138; 1,000 feet west and 660 feet north of the southeast corner of section 14, T. 26 S., R. 4 W.
RANGE IN CHARACTERISTICS: The soil is usually moist, but is dry throughout the control section for 60 to 90 consecutive days during the summer. The mean annual soil temperature is 52 to 57 degrees F. Depth to a paralithic contact is greater than 60 inches. The thickness of the mollic epipedon is 10 to 20 inches. Rock fragments are predominantly volcanic in origin and are in various stages of decomposition dependent upon lithology. Hue is 10YR or 7.5YR.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It has 40 to 60 percent total coarse fragments, with 20 to 35 percent gravel and 20 to 35 percent cobbles.
The Bt horizon has value of 3 or 4 moist, 4 through 6 dry and chroma of 4 through 6 moist and dry. It is extremely cobbly loam or clay loam, or extremely gravelly clay loam, averaging 25 to 35 percent clay. It has 20 to 50 percent gravel and 20 to 40 percent cobbles. Clay films are predominantly faint or distinct. Variegated colors are common throughout as a result of differential weathering of the rock fragments
COMPETING SERIES: These are the Bluesprin, Bobbitt, Briedwell, Keuterville, Sallyann, Tekoa, and Vilot series. Bluesprin, Bobbitt, and Sallyann soils are 20 to 40 inches deep to a lithic contact and have 47 to 52 degrees F. mean annual soil temperature. Briedwell soils lack an argillic horizon. Keuterville soils have mean annual soil temperature of 47 to 50 degrees F., formed in part from loess, and have 35 to 50 percent clay in the lower part of the argillic horizon. Tekoa and Vilot soils have a paralithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Fordice soils are on old terraces associated with the North and South Umpqua Rivers. Elevations range from 500 to 1,400 feet. Slopes are 0 to 12 percent. The soils formed in mixed medium textured gravelly and cobbly alluvium. Winters are cool and moist and summers are warm and dry. The mean annual temperature is 50 to 55 degrees F. and the annual precipitation is 30 to 60 inches. The frost-free season is 160 to 235 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Oakland, Pengra, Roseburg, Sutherlin and Waldo soils. Oakland, Pengra, Roseburg and Sutherlin soils have less than 35 percent rock fragments in the particle-size control section. Also, Oakland soils have a paralithic contact at a depth of 20 to 40 inches; Pengra soils are somewhat poorly drained; Roseburg soils have a mollic epipedon 20 inches or more thick; and Sutherlin soils have an ochric epipedon. Waldo soils are poorly drained, average more than 35 percent clay in the control section, and have a mollic epipedon 20 to 24 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used primarily for grazing and improved pasture. Small localized areas have been cultivated where the lower range of cobbles and stones is present. Native vegetation is Oregon white oak, sweetbriar rose, coast willow, Oregon ash and grasses.
DISTRIBUTION AND EXTENT: Interior valleys of the North and South Umpqua Rivers in Southwestern Oregon; MLRA 5. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Douglas County, Oregon, 1994.
REMARKS: The superactive cation exchange activity class was added to the classification in 10/2005. The competing series section was not updated at that time. Last revision 2/1996.