LOCATION GUSTIN OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Aquic Palehumults
TYPICAL PEDON: Gustin clay loam, on a northeast-facing slope of 15 percent under a regenerated coniferous forest at an elevation of 2,680 feet. (Colors are for moist soil unless otherwise stated.)
A1--0 to 3 inches; very dark grayish brown (10YR 3/2) clay loam, dark brown (10YR 3/3) dry; moderate very fine, fine and medium granular structure; hard, firm, sticky and slightly plastic; many very fine and common fine roots; many very fine and fine irregular pores; 5 percent soft tuff gravel; moderately acid; clear wavy boundary. (2 to 5 inches thick)
A2--3 to 7 inches; dark brown (10YR 3/3) clay loam, brown (10YR4/3) dry; moderate fine and medium subangular blocky structure; hard, firm, very sticky and plastic; common very fine, fine, medium and coarse roots; many very fine and fine irregular pores; very strongly acid; clear smooth boundary. (3 to 5 inches thick)
Bw--7 to 16 inches; brown (7.5YR 4/4) clay, dark yellowish brown (10YR 4/4) dry; dark yellowish brown (10YR 3/4) organic coatings moist; moderate fine and medium subangular blocky structure; very hard, firm, very sticky and plastic; common very fine, fine, medium, and coarse roots; common very fine and fine tubular pores; 5 percent soft tuff gravel; very strongly acid; gradual wavy boundary. (0 to 10 inches thick)
Btg1--16 to 24 inches; brown (7.5YR 4/4) clay, dark yellowish brown (10YR 4/4) dry; moderate medium and coarse subangular blocky structure; very hard, firm, very sticky and plastic; common very fine, fine, medium, and coarse roots; common distinct clay films on faces of peds and lining pores; common fine prominent grayish brown (2.5Y 5/2) iron depletions; common very fine tubular pores; 10 percent soft tuff gravel; extremely acid; clear smooth boundary. (6 to 9 inches thick)
Btg2--24 to 36 inches; grayish brown (2.5Y 5/2) and yellowish red (5YR 5/8) clay, light brownish gray (2.5Y 6/2) and strong brown (7.5YR 5/8) dry; moderate medium and coarse subangular blocky structure; very hard, firm, very sticky and plastic; common very fine roots; many prominent clay films on faces of peds and lining pores; common very fine tubular pores; the areas that are grayish brown are iron depletions; the areas that are yellowish red are masses of iron accumulation; 15 percent soft tuff gravel; very strongly acid; abrupt smooth boundary. (10 to 15 inches thick)
Btg3--36 to 40 inches; grayish brown (2.5Y 5/2) and yellowish red (5YR 5/8) clay, light brownish gray (2.5Y 6/2) and strong brown (7.5YR 5/8) dry; moderate medium and coarse subangular blocky structure; hard, friable, very sticky and plastic; common very fine roots; common prominent clay films on peds and lining pores; common very fine tubular pores; areas that are grayish brown are iron depletions; the areas that are yellowish red are masses of iron accumulation; 20 percent soft tuff gravel; extremely acid; abrupt smooth boundary. (3 to 6 inches thick)
Btg4--40 to 46 inches; grayish brown (2.5Y 5/2) and yellowish red (5YR 5/8) clay, light brownish gray (2.5Y 6/2) and strong brown (7.5YR 5/8) dry; moderate medium and coarse subangular blocky structure; very hard, very firm, very sticky and plastic; few very fine roots; common distinct clay films on faces of peds and lining pores; common very fine tubular pores; the areas that are yellowish red are masses of iron accumulation; 25 percent soft tuff gravel; extremely acid; clear wavy boundary. (4 to 8 inches thick)
Btg5--46 to 60 inches; grayish brown (2.5Y 5/2) clay, light brownish gray (2.5Y 6/2) dry; moderate medium and coarse subangular blocky structure; very hard, firm, very sticky and plastic; few very fine roots; common distinct clay films on peds and lining pores; common very fine tubular pores; common fine prominent yellowish red (5YR 5/8) masses of iron accumulation; 15 percent soft tuff gravel; extremely acid.
TYPE LOCATION: Douglas County, Oregon; 1 mile northeast of Sampson Butte; 420 feet west and 1,735 feet north of the S.E.corner of section 25, T. 27 S., R. 3 W., W.M.
RANGE IN CHARACTERISTICS: Thickness of the solum commonly is 60 inches or more but is as thin as 40 inches in some pedons. The mean annual soil temperature is 47 to 55 degrees F. The soil is usually moist and is dry between 4 and 12 inches for less than 45 consecutive days during the summer. It is very strongly acid or extremely acid. Depth to redox depletions with chroma of less than 2 is 10 to 20 inches.
The A horizon has value of 3 or 4 moist,3 through 5 dry and chroma of 1 through 4 moist and dry. Hard rock fragments range from 0 to 10 percent gravel. Soft tuff fragments range from 0 to 5 percent. It is very strongly acid to moderately acid.
The Btg horizons have matrix hue of 2.5Y, 5Y, or 10YR moist and 2.5Y or 5Y dry, value of 4 through 6 moist, 6 through 8 dry and chroma of 1 through 4 moist and dry. Redox concentrations have hue of 5YR or 7.5YR. It is clay or silty clay averaging 40 to 55 percent clay. Soft tuff fragments range from 0 to 25 percent. It is extremely acid to strongly acid.
COMPETING SERIES: There are no other series in the same family. The Telemon and Zing series are similar. Telemon soils are frigid. Zing soils are xeric.
GEOGRAPHIC SETTING: Gustin soils on foot slopes, benches and mountain side slopes. Elevation ranges from 800 to 3,500 feet. These soils formed in residuum and colluvium derived dominantly from ash-flow tuffs. Slopes are 0 to 45 percent. The mean annual temperature ranges from 45 to 53 degrees F. The mean annual precipitation is 50 to 75 inches. The frost-free period is 100 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Honeygrove, Klickitat, Orford and Shivigny soils. All of these soils are well drained. Honeygrove and Shivigny soils have hue of 2.5YR and 5YR in the argillic horizon. Shivigny soils are clayey-skeletal. Klickitat soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Somewhat poorly and moderately well drained; slow permeability. A perched water table is at a depth of 1 to 3 feet from November to May.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat and watershed. A few areas are used for pasture. The native vegetation includes Douglas fir, western redcedar, grand fir, and western hemlock. The understory is dominantly salal, western swordfern, vine maple, violet, cascade Oregon grape, trailing blackberry, red huckleberry, long tube twinflower, rose, pacific rhododendron and pyrola.
DISTRIBUTION AND EXTENT: Western Cascade Mountains of southern Oregon; MLRA 3. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1974.
REMARKS: This draft reflects a change in classification from Aquultic Hapludalfs to Aquic Palehumults.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to about 7 inches. (A1 and A2 horizons).
Argillic horizon - The zone from approximately 7 to 60 inches. (Bw, Btg1, Btg2, Btg3, Btg4 and Btg5 horizons)
Aquic feature - the zone from 16 to 36 inches (Btg1 and Btg2 horizons) having redox depletions with color value of 4 and chroma of 2 with redox concentrations (Btg2 horizon). Aquic conditions are present for some time in most years.
Mixed mineralogy - presumed to be mixed by previous field experience.
Episaturation assumed
Pale feature - the zone from 0 to 60 inches having no clay decrease by 20 percent.