LOCATION GREGORY OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Argiaquolls
TYPICAL PEDON: Gregory silty clay loam, on a 1 percent slope in a cultivated field. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) silty clay loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many very fine and fine roots; common fine irregular pores; slightly acid (pH 6.2) abrupt smooth boundary. (6 to 8 inches thick)
A--7 to 12 inches; very dark grayish brown (10YR 3/2) clay loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; many very fine irregular pores; slightly acid (pH 6.2) clear smooth boundary. (4 to 7 inches thick)
BA--12 to 18 inches; very dark grayish brown (10YR 3/2) clay loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; common fine tubular pores; slightly acid (pH 6.1) clear smooth boundary. (4 to 7 inches thick)
Bt1--18 to 29 inches; very dark grayish brown (10YR 3/2) clay, grayish brown (10YR 5/2) dry; common distinct mottles; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine tubular pores; common thin clay films; moderately acid (pH 6.0) gradual wavy boundary. (9 to 13 inches thick)
Bt2--29 to 44 inches; dark grayish brown (2.5Y 4/2) clay, grayish brown (2.5Y 5/2) dry; many distinct yellowish red (5YR 4/6) mottles; strong coarse angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine tubular pores; common moderately thick clay films; moderately acid (pH 5.8); gradual wavy boundary. (13 to 17 inches thick)
2C--44 to 50 inches; dark grayish brown (2.5Y 4/3) sandy clay loam, light brownish gray (2.5Y 6/3), many distinct yellowish red (5YR 4/6) mottles; massive; very hard, very firm, sticky and plastic; few very fine tubular pores; moderately acid (pH 5.8); gradual wavy boundary. (4 to 8 inches thick)
3Cr--50 inches; weathered sandstone.
TYPE LOCATION: Jackson County, Oregon; about 1 mile northwest of Lower Table Rock, approximately 2,200 feet west and 440 feet south of the northeast corner of sec. 6, T. 36 S., R. 2 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 52 to 57 degrees F. The soils are usually moist but are dry at depths between 4 to 12 inches for 70 to 100 consecutive days after the summer solstice. Depth to weathered bedrock is 40 to over 60 inches. A seasonal water table occurs at a depth of 0 to 1 feet from December through May. The particle-size control section averages 35 to 45 percent clay and 0 to 15 percent gravel. The mollic epipedon is 23 to 35 inches thick.
The A horizon has hue of 10YR or 2.5Y, value of 2 or 3 moist, 3 through 5 dry, and chroma of 2 moist and 2 or 3 dry.
The Bt horizon has hue of 10YR or 2.5Y, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is clay or clay loam. Gravel content is 0 to 15 percent. It is medium to slightly acid.
The 2C horizon has value of 4 or 5 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is sandy clay loam or clay loam.
COMPETING SERIES: These are the Bremer, Chancellor, Crossplain, Edinburg, Haig, Mazaska, Minnetonka, Taintor, Virden, Winterset, Worthenton, and Worthing soils. All of these soils lack the 70 to 100 consecutive day dry period during the summer months. Bremer soils have chroma of 1 or less throughout a depth of 24 to 36 inches from the surface. Chancellor soils have carbonates at a depth of 25 to 50 inches and have accumulations of gypsum and other salts in the lower part of the subsoil, in most pedons. Crossplain soils have carbonates at a depth of 16 to 48 inches and has chroma of 1 or less throughout the A horizon. Edinburg soils have a mollic epipedon 10 to 24 inches thick. Haig soils have chroma of 1 or less throughout the mollic epipedon. Mazaska soils have carbonates at a depth of 30 to 60 inches, and have a mollic epipedon 10 to 22 inches thick. Minnetonka soils have carbonates at a depth of 28 to 52 inches and have chroma of 1 or less throughout the A horizon. Taintor soil have a mollic epipedon 12 to 24 inches thick. Winterset soils have chroma of 1 or less throughout the A horizon. Worthenton soils have a mollic epipedon 7 to 20 inches thick and are effervescent throughout the profile. Worthing soils have carbonates at a depth of 35 to 60 inches, have chroma of 1 or less throughout the A horizon and Bt horizon, and have a mollic epipedon over 35 inches thick.
GEOGRAPHIC SETTING: Gregory soils are on terraces at elevations of 1,000 to 2,000 feet. Slopes are 0 to 3 percent. The soils formed in alluvium dominantly from sedimentary and metamorphic rocks. The climate is characterized by warm wet winters and hot dry summers. The mean annual temperature is 50 to 54 degrees F; the mean winter temperature is 35 to 38 degrees F, and the mean summer temperature is 69 to 72 degrees F. The mean annual precipitation is 18 to 30 inches. The frost-free period is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carney, Coker and the competing Medford soils. Carney soils are very-fine, moderately well drained and crack to the surface. Coker soils are very-fine and crack to the surface. Medford soils are moderately well drained with mottles at 40 or more inches in depth.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow to slow runoff; slow permeability. It has a water table at 0 to 1 foot from December to May.
USE AND VEGETATION: Gregory soils are used for cultivated crops, hay, and pasture. Native vegetation is dominantly grasses with some rushes and sedges.
DISTRIBUTION AND EXTENT: Inland valleys of southwestern Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Jackson County Area, Oregon, 1988.
REMARKS: Diagnostic horizons and features:
Mollic epipedon - the zone from 0 to 29 inches (Ap, A, BA, Bt1).
Argillic horizon - the zone from 18 to 44 inches (Bt1, Bt2).
Montmorillonitic clay mineralogy based on geographically associated soils.
Aquic soil moisture regime - the lower part of the mollic epipedon (18 to 29 inches) has moist chroma of 2 and distinct mottles.
The series was missclassified (Pachic Argixeroll) and mineralogy was keyed in as mixed.
Series Revision Date: 7/11/89