LOCATION SWEETBRIAR OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ultic Haploxeralfs
TYPICAL PEDON: Sweetbriar silty clay loam- forested, on a southwest-facing slope of 59 percent at an elevation of 2270 feet. (Colors are for moist soil unless otherwise stated.)
Oi--0.5 inch to 0; slightly decomposed needles, leaves, twigs, bark and cone fragments.
A1--0 to 3 inches; very dark grayish brown (10YR 3/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular and moderate very fine subangular blocky structure; hard, firm, sticky and plastic; many very fine and common fine, medium and coarse roots; many very fine and fine irregular pores; 10 percent gravel; moderately acid (pH 5.8); clear smooth boundary. (2 to 3 inches thick)
A2--3 to 8 inches; very dark grayish brown (10YR 3/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine subangular blocky structure; very hard, firm, sticky and plastic; many very fine, and common fine, medium and coarse roots; common very fine and fine irregular pores; 10 percent gravel; moderately acid (pH 5.8); clear smooth boundary. (4 to 6 inches thick)
Bt1--8 to 18 inches; dark brown (10YR 3/3) clay, brown (10YR 4/3) dry; moderate fine and medium subangular blocky structure; very hard, very firm, sticky and plastic; common very fine, fine, medium and coarse roots; common very fine and fine tubular pores; common faint clay films on peds and lining pores; 5 percent gravel; moderately acid (pH 5.6); clear wavy boundary.
Bt2--18 to 23 inches; dark yellowish brown (10YR 4/4) clay, yellowish brown (10YR 5/4) dry; moderate medium and coarse subangular blocky structure; very hard, very firm, very sticky and plastic; common very fine, fine, medium and coarse roots; common very fine and fine tubular pores; common distinct clay films on peds and lining pores; 5 percent gravel; strongly acid (pH 5.4); clear wavy boundary.
Bt3--23 to 29 inches; dark yellowish brown (10YR 4/6) clay, yellowish brown (10YR 5/6) dry, moderate medium and coarse subangular blocky structure; very hard, very firm, very sticky and plastic; common very fine, fine, and medium roots; common very fine and fine tubular pores; common distinct clay films on peds and lining pores; 5 percent gravel; strongly acid (pH 5.2); clear wavy boundary.
Bt4--29 to 38 inches; dark yellowish brown (10YR 4/6) clay, yellowish brown (10YR 5/6) dry, moderate medium and coarse subangular blocky structure; very hard, very firm, very sticky and plastic; common very fine, fine, medium and coarse roots; common very fine and fine tubular pores; common distinct clay films on peds and lining pores; very strongly acid (pH 4.8); clear wavy boundary.
Bt5--38 to 53 inches; yellowish brown (10YR 5/6) silty clay loam, brownish yellow (10YR 6/6)dry; moderate medium and coarse subangular blocky structure; very hard, very firm, very sticky and plastic; common very fine, fine, medium and coarse roots; common fine tubular pores; common distinct clay films on peds and lining pores; very strongly acid (pH 4.8); clear wavy boundary.
Bt6--53 to 60 inches; dark yellowish brown (10YR 4/4) clay loam, yellowish brown (10YR 5/4) dry; weak very fine and fine subangular blocky structure; slightly hard, firm, sticky and plastic; common very fine, fine, medium and coarse roots; common very fine and fine irregular pores; few moderately thick clay films on peds; very strongly acid (pH 4.8). (Combined thickness of the Bt horizon is over 50 inches)
TYPE LOCATION: Douglas County, Oregon; 3 1/4 miles north-northwest of Tiller, Oregon; 2,260 feet south and 735 feet east of the N.W. c.rner of section 14, T. 30 S., R. 2 W., W. M. (Latitude 42 degrees, 58 minutes, 9 seconds N, Longitude 122 degrees, 55 minutes, 8 seconds W)
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock is 60 inches or more. The mean annual soil temperature is 49 to 56 degrees F. The soil is usually moist but is dry between 4 and 12 inches for 45 to 60 consecutive days during the summer. It has 0 to 15 percent gravel throughout the solum. The mollic epipedon is 10 to 20 inches thick. Hue is 10YR or 7.5YR.
The A horizon has chroma of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and 2 to 4 dry. It is slightly acid to strongly acid. Base saturation is 50 to 75 percent by ammonium acetate. It has 5 to 8 percent organic matter.
The upper part of the Bt horizon has value of 3 to 5 moist and 4 to 6 dry, and chroma of 3 to 6 moist and dry. It is silty clay or clay with 40 to 55 percent clay. It is moderately acid to very strongly acid. Base saturation is 35 to 60 percent by ammonium acetate.
The lower part of the Bt horizon, when present, has value of 3 to 5 moist, 4 to 6 dry and chroma of 4 to 6 moist and dry. It is clay loam or silty clay loam with 27 to 40 percent clay. It is strongly acid or very strongly acid. Base saturation is 35 to 50 percent by ammonium acetate.
COMPETING SERIES: These are the Cedargrove, Cornutt, Freezener, Greengulch, Jumpoff, Mildred, Oak Grove, Oakland, Rainier, and Veneta series. Cedargrove soils are dry for 60 to 90 days and have an ochric epipedon. Cornutt soils have a Ca/Mg ratio of more than 1, have hue of 5YR or 2.YR in the subsoil and are deep to bedrock. Freezener soils have dominant hue of 5YR or 2.5YR in the argillic horizon and are dry for 60 to 90 days. Greengulch, Mildred, and Oakland soils have a paralithic contact at 20 to 40 inches. Jumpoff soils are moderately well drained and have hue of 5Y or 2.5Y in the argillic horizon. Oak Grove soils have an umbric epipedon and are dry for 60 to 80 days. Rainier soils are moderately well drained and have a lithic contact at a depth of 40 to 60 inches. Veneta soils have more than 60 percent clay in the lower part of the argillic horizon.
GEOGRAPHIC SETTING: Sweetbriar soils are on mountain sideslopes. Elevation ranges from 800 to 3,000 feet. These soils formed in residuum and colluvium derived dominantly from ash-flow tuffs, flow basalts, flow breccia and metasediments. Slopes are 3 to 60 percent. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual temperature is 47 to 54 degrees F., and the mean annual precipitation is 35 to 60 inches. The frost-free period is 100 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beal, Chamate, Dumont, Lettia, Sharpshooter and Zing soils. The Beal, Lettia, and Sharpshooter soils are fine-loamy. The Chamate soils are loamy-skeletal. Dumont soils are Ultisols and have hue of 5YR and 2.5YR in the control section. Zing soils are somewhat poorly and moderately well drained.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat and watershed. The native vegetation includes Douglas fir, incense cedar, ponderosa pine and grand fir with an understory of salal, western swordfern, cascade Oregongrape, American twinflower, Pacific dogwood, common snowberry, and golden chinkapin.
DISTRIBUTION AND EXTENT: Klamath Mountain province and western Cascade Mountain province of southwestern Oregon; MLRA 5. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Douglas County, Oregon, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon- the zone from the surface of the mineral soil to a depth of approximately 18 inches. (A1, A2 and Bt1 horizons)
Argillic horizon- the zone from approximately 8 to 60 inches. (Bt1, Bt2, Bt3, Bt4, Bt5, and Bt6 horizons)
Particle-size control section- from 8 to 28 inches. (Bt1, Bt2, and part of the Bt3 horizons) with estimated clay content of 45 percent.
Ultic intergrade- base saturation is assumed to be 35 to 60 percent throughout the argillic horizon, decreasing with depth. (Thus the soil is not a Mollisol)
Mollic intergrade- color value of 3 moist in the A horizon with more than 0.7 percent organic carbon.
Placement into Haploxeralfs is based on the modal profile. Areas of this soil that have hue of 7.5YR and chroma of more than 4 in the matrix of the argillic horizon would qualify as Palexeralfs. This problem exists in many of the series of Ultic Haploxeralfs. A change is needed in the keys to address this problem; recommend changing hue to be redder than 7.5YR instead of redder than 10YR
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 3/1995.