LOCATION BURNTHILL OREstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, superactive, isomesic Typic Palehumults
TYPICAL PEDON: Burnthill loam, woodland, on a 2 percent slope at an elevation of 470 feet. (When described on October 6, 1988 the profile was moist throughout. Colors are for moist soil unless otherwise noted.)
Oi--2 inches to 0; partially decomposed needles, leaves, twigs, woody materials.
A1--0 to 3 inches; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine subangular blocky structure parting to weak fine granular; slightly hard, friable, nonsticky and nonplastic, weakly smeary; many fine and very fine and few medium and coarse roots; many fine and very fine irregular pores; very strongly acid (pH 4.9); clear smooth boundary.
A2--3 to 11 inches; very dark grayish brown (10YR 3/2) loam, dark brown (10YR 4/3) dry; weak very fine subangular blocky structure parting to weak fine granular; slightly hard, friable, nonsticky and nonplastic, weakly smeary; many fine and very fine and few medium and coarse roots; many very fine and fine irregular pores; very strongly acid (pH 4.5); abrupt smooth boundary. (Combined thickness of the A horizon ranges from 10 to 20 inches)
2Bt1--11 to 23 inches; dark brown (7.5YR 3/4) loam, strong brown (7.5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and very fine and few medium and coarse roots; many very fine continuous tubular pores; few faint clay films on ped faces, common faint clay films in pores; 10 percent (2 to 5 mm) manganese concretions and 15 percent soft rock fragments; very strongly acid (pH 4.9); gradual smooth boundary.
2Bt2--23 to 31 inches; reddish brown (5YR 4/4) loam, strong brown (7.5YR 5/8) dry; moderate medium and coarse subangular blocky structure; hard, firm, sticky and plastic; common fine and few medium and coarse roots; common very fine continuous tubular pores; common distinct clay films on ped faces and in pores; 10 percent (2 to 5 mm) manganese concretions and 15 percent soft rock fragments; very strongly acid (pH 5.0); clear smooth boundary.
2Bt3--31 to 36 inches; brown (7.5YR 4/4) clay loam, strong brown (7.5YR 5/6) dry; moderate medium and coarse subangular blocky structure; hard, firm, sticky and plastic; common fine and few medium and coarse roots; many very fine continuous tubular pores; common distinct clay films on ped faces and in pores; 10 percent (2 to 5 mm) manganese concretions and 15 percent soft rock fragments; very strongly acid (pH 5.0); gradual smooth boundary.
2Bt4--36 to 43 inches; strong brown (7.5YR 4/6) clay loam, strong brown (7.5YR 5/8) dry; weak medium subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; common fine continuous tubular pores; common distinct clay films on ped faces and in pores; 10 percent (2 to 5 mm) manganese concretions and 15 percent soft rock fragments; very strongly acid (pH 5.0); gradual smooth boundary. (Combined thickness of the 2Bt horizon ranges from 29 to 47 inches)
2BC--43 to 51 inches; yellowish red (5YR 4/6) clay loam, strong brown (7.5YR 5/8) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; common fine continuous tubular pores; 20 percent (2 to 5 mm) manganese concretions and 25 percent soft rock fragments; very strongly acid (pH 5.0); gradual smooth boundary. (6 to 15 inches thick)
2C--51 to 60 inches; yellowish red (5YR 4/6) clay loam, reddish yellow (5YR 6/6) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine continuous tubular pores; 20 percent (2 to 5 mm) manganese concretions and 25 percent soft rock fragments; very strongly acid (pH 5.0).
TYPE LOCATION: Curry County, Oregon; located about 750 feet south and 2220 feet east of the northwest corner of section 31, T. 40 S., R. 13 W., W.M. (Latitude 42 degrees, 4 minutes, 31 seconds N, Longitude 124 degrees, 17 minutes, 30 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 54 degrees F. The difference between mean summer and mean winter soil temperature varies from 5 to 9 degrees F. The soils are usually moist and are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches in the four months following the summer solstice. The particle-size control section averages 25 to 35 percent clay. Depth to bedrock is greater than 60 inches. The solum is very strongly acid throughout. The umbric epipedon is 10 to 20 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. It is loam with 10 to 20 percent clay and 0 to 10 percent gravel. It is weakly smeary throughout.
The 2Bt horizon has hue of 7.5YR or 5YR, value of 3 or 4 moist, 4 or 5 dry and chroma of 4 to 6 moist and 6 to 8 dry. It is loam or clay loam with 25 to 35 percent clay. It has 10 to 20 percent soft rock fragments, 10 to 20 percent (2 to 5 mm) concretions, and 0 to 10 percent gravel greater than 5 mm in size.
The 2BC horizon has hue of 7.5YR or 5YR, value of 4 to 6 moist, 5 or 6 dry and chroma of 6 to 8 moist and dry. It is loam or clay loam with 25 to 35 percent clay. It has 20 to 30 percent soft rock fragments, 20 to 30 percent (2 to 5 mm) concretions, and 0 to 10 percent gravel greater than 5 mm in size.
The 2C horizon has hue of 7.5YR or 5YR, value of 4 to 6 moist, 6 to 8 dry and chroma of 6 to 8 moist and dry. It is loam or clay loam with 25 to 35 percent clay. It has 20 to 40 percent soft rock fragments, 30 to 40 percent (2 to 5 mm) concretions, and 0 to 10 percent gravel greater than 5 mm in size.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Burnthill soils are on broad tops and side slopes of deeply dissected high marine terraces. Slopes are 0 to 30 percent. The soils formed in marine sediments. Elevations are 400 to 1,500 feet. The climate is humid, characterized by cool wet winters and cool moist summers with fog. A strong marine influence limits the diurnal and annual range of temperature. The mean annual precipitation is 70 to 90 inches. The mean annual temperature is 50 to 53 degrees F. The frost-free period is 210 to 300 days. Burnthill soils are on the Griggs geomorphic surface.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cashner, Cunniff, and Joeney soils. Cashner soils are poorly drained, have a spodic horizon, and are on dissected marine terraces. Cunniff soils have 35 to 45 percent clay in the argillic horizon and are on an adjacent lower marine terrace. Joeney soils are poorly drained, have a spodic horizon, and are on an adjacent lower marine terrace.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for homesites, timber production, recreation, watershed, pasture, and wildlife habitat. Native vegetation is Sitka spruce, Douglas fir, red alder, red elderberry, salmonberry, evergreen huckleberry, salal, western swordfern, evergreen violet, and sweetscented bedstraw.
DISTRIBUTION AND EXTENT: Pleistocene marine terraces in southwestern Oregon and possibly northwestern California; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995. The source of the name is a creek in coastal southwestern Curry County.
REMARKS: Diagnostic horizons and features in this pedon include:
Umbric epipedon - from the surface to a depth of 11 inches (A1, A2 horizons).
Argillic horizon - from a depth of 11 to 43 inches (2Bt1, 2Bt2, 2Bt3, 2Bt4 horizons).
Palehumults great group - the clay percentage does not decrease from its maximum amount by as much as 20 percent within a depth of 60 inches from the surface.
Humults suborder - the soil has 2.1 percent organic carbon in the upper 6 inches of the argillic horizon (2Bt1 horizon) and 49.1 kg/meter squared of organic carbon to a depth of 40 inches.
ADDITIONAL DATA: Reference samples with partial laboratory data from pedon 89P 197, samples 89P1199-1202 from Curry County, Oregon, samples by NSSL, Lincoln, NE, 12/89