LOCATION SAWTELL OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Oxyaquic Argixerolls
TYPICAL PEDON: Sawtell silt loam, on a 3 percent north-facing slope in a fallow field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine tubular pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (5 to 8 inches thick)
A--6 to 13 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine tubular pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (5 to 12 inches thick)
BA--13 to 20 inches; dark brown (10YR 3/3) gravelly clay loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine, fine, and medium roots; many very fine tubular pores; 20 percent gravel and 5 percent cobbles; common coarse manganese concretions; strongly acid (pH 5.2); clear smooth boundary. (5 to 10 inches thick)
2Bt1--20 to 29 inches; brown (10YR 4/3) very gravelly clay loam, yellowish brown (10YR 5/4) dry;moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine, fine, and medium roots; many very fine tubular pores; common distinct dark yellowish brown (10YR 4/4) clay films; 30 percent gravel and 10 percent cobbles; many coarse manganese concretions; few medium distinct strong brown (7.5YR 5/6) redox concentrations; strongly acid (pH 5.2); gradual smooth boundary. (5 to 15 inches thick)
2Bt2--29 to 43 inches; brown (10YR 4/3) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; common very fine tubular pores; common distinct dark yellowish brown (10YR 4/4) clay films; 50 percent gravel and 10 percent cobbles; common fine and medium distinct strong brown (7.5YR 5/6) redox concentrations and grayish brown (10YR 5/2) redox depletions;strongly acid (pH 5.2); clear smooth boundary. (10 to 20 inches thick)
2C--43 to 60 inches; yellowish brown (10YR 5/4) very gravelly clay, light yellowish brown (10YR 6/4) dry; massive; very hard, very firm, very sticky and very plastic; common very fine tubular pores; 40 percent gravel and 15 percent cobbles; many coarse distinct grayish brown (10YR 5/2) redox depletions and yellowish brown (10YR 5/8) redox concentrations; strongly acid (pH 5.4). (15 to 30 inches thick)
TYPE LOCATION: Clackamas County, Oregon; about one mile southwest of Molalla and 100 meters south of the end of Ona Way; in the NW1/4SE1/4NE1/4 section 18, T. 5 S., R 2 E.
RANGE IN CHARACTERISTICS: The soil is usually moist but is dry for 45 to 60 consecutive days during the summer between depths of 4 and 12 inches. The mean annual soil temperature is 52 to 54 degrees F. Depth to the lithologic discontinuity ranges from 15 to 25 inches. Depth to bedrock is 60 inches or more. The mollic epipedon ranges from 10 to 20 inches thick. Depth to redox depletions with a chroma of 2 or less is 30 inches or more.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. Texture is silt loam or loam. Rock fragments range from 0 to 15 percent gravel. Clay content is 20 to 27 percent. Soil reaction is strongly acid or moderately acid.
The 2Bt horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry and chroma of 3 or 4 moist and dry. Texture is very gravelly clay loam or loam or extremely gravelly loam. Rock fragments range from 30 to 50 percent gravel and 5 to 20 percent cobbles. Clay content is 25 to 35 percent.
The 2C horizon has hue of 10YR or 7.5YR, value of 4 or 5 moist, 5 or 6 dry, and chroma of 3 to 5 moist and dry. Texture is very gravelly clay or clay loam or extremely gravelly clay loam. Rock fragments range from 30 to 60 percent gravel and 5 to 20 percent cobbles. Clay content is 35 to 45 percent.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Sawtell soils are on terraces at elevations of 300 to 500 feet. Slopes are 0 to 15 percent. Sawtell soils formed in gravelly old alluvium. The climate is charactertized by cool wet winters and warm dry summers. The mean annual precipitation is 45 to 55 inches. The mean annual temperature is 50 to 54 degrees F. The frost-free period is 165 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clackamas, Dayton and Amity soils. Clackamas soils are mottled above 20 inches. Dayton soils are poorly drained, are in a fine family, and have fewer than 15 percent rock fragments within the particle-size control section. Amity soils have mottles above 20 inches and have fewer than 15 percent rock fragments within the particle-size control section. These soils are on terraces.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow or medium runoff; moderately slow permeability.
USE AND VEGETATION: Sawtell soils are used for pasture, hay, grain, and Christmas tree production. Native vegetation is Douglas-fir, Oregon white oak, wild rose, trailing blackberry, and grasses.
DISTRIBUTION AND EXTENT: It is in the southwestern part of Clackamas County, Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clackamas County, Oregon, 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - the zone from 0 to 20 inches (Ap, A and BA horizons)
Argillic horizon - the zone from 20 to 43 inches
Oxyaquic feature - the zone beginning at 29 inches with redox depletions of chroma 2 or less
Ultic feature - assumed base saturation of 75 percent or less (summ) in some horizon between 10 and 30 inches.
Series revision date - 09/2002 with classification revised from loamy-skeletal, mixed, mesic Ultic Argixerolls to loamy-skeletal, mixed, superactive, mesic Oxyaquic Argixerolls.