LOCATION GELLATLY OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Pachic Argixerolls
TYPICAL PEDON: Gellatly silty clay loam, homesite. (Colors are for moist soil unless otherwise noted.)
A--0 to 8 inches; very dark brown (10YR 2/2) silty clay loam, brown (10YR 4/3) dry; strong fine granular structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine and few fine, medium and coarse roots; many very fine irregular pores; 2 percent gravel; slightly acid (pH 6.1); abrupt smooth boundary (5 to 10 inches thick).
BAt--8 to 14 inches; very dark brown (10YR 2/2) silty clay loam, brown (10YR 4/3) dry; moderate medium subangular blocky parting to moderate fine subangular blocky structure; moderately hard, friable, moderately sticky and very plastic; common very fine and few fine, medium, and coarse roots; many very fine, fine, and medium pores; few faint clay films on faces of peds and along pores; 2 percent gravel; slightly acid (pH 6.2); clear smooth boundary (5 to 10 inches thick).
Bt--14 to 29 inches; dark brown (7.5YR 3/2) clay, brown (7.5YR 4/2) dry; weak medium prismatic parting to moderate medium subangular blocky structure; very hard, friable, moderately sticky and very plastic; common very fine and few fine, medium, and coarse roots; many very fine and common fine and medium tubular pores; many distinct clay films on faces of peds and along pores; slightly acid (pH 6.3); clear wavy boundary (10 to 20 inches thick).
BCt1--29 to 45 inches; dark yellowish brown (10YR 4/4 and 10YR 4/6) silty clay loam, yellowish brown (10YR 5/6), light yellowish brown (10YR 6/4), and brownish yellow (10YR 6/6) dry; massive; moderately hard, friable, moderately sticky and slightly plastic; few very fine, fine, medium, and coarse roots; many very fine tubular pores; few prominent very dark grayish brown (10YR 3/2) clay films along pores; neutral (pH 6.9); gradual wavy boundary.
BCt2--45 to 61 inches; dark grayish brown (10YR 4/2) and light yellowish brown (10YR 6/4) silty clay loam, brownish yellow (10YR 6/6), light yellowish brown (10YR 6/4), and brown (10YR 5/3) dry; massive; moderately hard, friable, moderately sticky and slightly plastic; few very fine roots; many very fine tubular pores; few prominent very dark grayish brown (10YR 3/2) clay films along pores; 10 percent paragravel; neutral (pH 7.1); abrupt wavy boundary (Combined thickness of the BCt horizon is 25 to 45 inches).
Cr--61 to 71 inches; moderately cemented basalt.
TYPE LOCATION: Benton County, Oregon; 2,400 feet east and 2,200 feet south of the NW corner of section 21, T. 11 S. , R. 5 W. Willamette Meridian. Corvallis, Oregon USGS 7.5 minute topographic quadrangle. (Latitude 44 degrees, 36 minutes, 4 seconds, North, Longitude 123 degrees, 18 minutes, 6 seconds, West, NAD 27)
RANGE IN CHARACTERISTICS: Soils are usually moist but are dry in all parts between depths of 4 and 12 inches for 45 to 60 consecutive days following the summer solstice. The mean annual soil temperature is 53 to 55 degrees F. The soil is 60 to 98 inches deep to a paralithic contact. The mollic epipedon is 20 to 36 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 3 or 4 dry, and chroma of 2 or 3 moist and dry. Texture is silty clay loam with 27 to 40 percent clay. It has 0 to 10 percent cobbles and 0 to 5 percent gravel. Reaction is moderately acid or slightly acid.
The BAt horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 3 or 4 dry, and chroma of 2 or 3 moist and dry. Texture of the fine-earth fraction is silty clay loam, clay or silty clay with 35 to 50 percent clay. It has 0 to 20 percent cobbles and 0 to 5 percent gravel. Reaction is moderately acid or slightly acid.
The Bt horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 or 3 moist and 2 to 4 dry. Texture is clay or silty clay with 40 to 55 percent clay. It has 0 to 5 percent cobbles and 0 to 5 percent gravel. Reaction is moderately acid or slightly acid.
The BCt horizon has value of 3 to 6 moist and 4 to 6 dry and chroma of 2 to 6 moist and dry. Texture of the fine-earth fraction is silty clay loam, silty clay or clay with 30 to 50 percent clay. The upper part has 0 to 15 percent paragravel and the lower part has 5 to 35 percent paragravel. Reaction is slightly acid or neutral.
COMPETING SERIES: This is the Nelsonridge (T) series.
Nelsonridge soils - the OSD for this soil has not been placed in the database and cannot be competed.
The
Darby soils have a similar classification.
Darby soils - have a mollic epipedon that is greater than 30 inches thick; does not have paragravel in the BCt horizon; base saturation of less than 75 percent (sum) between 10 and 75 cm.
GEOGRAPHIC SETTING: The Gellatly soils are on gently sloping to steep side slopes on hills at elevations of 300 to 1,500 feet. Slopes are 3 to 60 percent. The soils formed in clayey colluvium and residuum derived from basalt of the Siletz River Volcanics formation. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual precipitation is 45 to 60 inches. The mean annual temperature is 50 to 54 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bashaw, Dixonville, Philomath, and Witham soils. Bashaw soils are very fine, crack to the surface and are on toeslopes. Philomath soils are 12 to 20 inches deep to a paralithic contact and are on convex side slopes and ridges. Witham soils have redoximorphic features at depths of 10 to 30 inches and are on footslopes and toeslopes. Dixonville soils are on linear and convex side slopes and have a paralithic contact at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: These soils are used for home site development, hay and pasture, timber production, wildlife habitat, and watersheds. Native vegetation includes Oregon white oak, Douglas fir, Pacific poison oak, common snowberry, baldhip rose, and grasses.
DISTRIBUTION AND EXTENT: Gellatly soils are on hills along the margin of the Willamette Valley, Oregon; MLRA 2. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benton County, Oregon, 2004. The source of the name is from a family that settled in Benton County in the late 1800's.
REMARKS: Diagnostic horizons and features recognized in the pedon include:
Mollic epipedon - the zone from 0 to 29 inches (A, BAt, and Bt horizons)
Argillic horizon - the zone from 8 to 60 inches (BAt, Bt, BCt1, and BCt2 horizons)
Particle-size control section - the zone from 8 to 28 inches.
ADDITIONAL DATA: Characterization data for three pedons with Soil Survey Laboratory soil survey sample numbers; S00OR-003-001, S00OR-003-005,
and S00OR-003-006, NSSL, Lincoln, NE.