LOCATION ABSAQUIL OREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Haplohumults
TYPICAL PEDON: Absaquil silt loam - woodland on a west-facing slope of 45 percent at 1440 feet elevation. (Colors are for moist soil unless otherwise stated.)
Oi--1 1/2 inches to 0 ; duff layer of partially decomposed leaves, twigs and needles.
A1--0 to 4 inches; dark brown (7.5YR 3/2) silt loam, brown (7.5YR 5/4) dry; strong very fine and fine granular structure; very soft, very friable, slightly sticky and slightly plastic; many very fine, fine, medium, and common coarse roots; many very fine and fine irregular pores; 10 percent hard gravel, 10 percent soft siltstone gravel; strongly acid (pH 5.2); clear smooth boundary.
A2--4 to 10 inches; dark yellowish brown (10YR 3/4) silt loam, yellowish brown (10YR 5/4) dry; moderate fine and medium subangular blocky structure; very soft, friable, sticky and slightly plastic; many very fine, fine and common medium and coarse roots; many very fine and fine irregular pores; 5 percent hard gravel, 5 percent soft siltstone gravel; strongly acid (pH 5.2); clear smooth boundary. (Combined thickness of the A horizon is 6 to 13 inches)
Bt1--10 to 16 inches; brown (7.5YR 4/4) silty clay loam, strong brown (7.5YR 5/6) dry; moderate medium and coarse subangular blocky structure; slightly hard, firm, sticky and plastic; common fine and medium roots; common very fine, fine and medium irregular and tubular pores; common prominent yellowish red (5YR 4/6) clay films in pores; 5 percent hard gravel, 5 percent soft siltstone gravel; very strongly acid (pH 4.8); clear smooth boundary.
Bt2--16 to 26 inches; strong brown (7.5YR 4/6) silty clay loam, strong brown (7.5YR 5/6) dry; moderate medium and coarse subangular blocky structure; hard, firm, sticky and plastic; common fine and medium roots; common very fine and fine tubular pores; many prominent yellowish red (5YR 4/6) clay films on faces of peds and in pores; 5 percent hard gravel, 10 percent soft siltstone gravel, very strongly acid (pH 4.6); clear smooth boundary.
Bt3--26 to 32 inches; strong brown (7.5YR 4/6) silty clay, reddish yellow (7.5YR 6/6) dry; moderate medium and coarse subangular blocky structure; hard, firm, very sticky and very plastic; common fine and medium roots; common very fine and fine tubular pores; many prominent yellowish red (5YR 4/6) clay films on faces of peds, in pores, and coating rock fragments; 10 percent hard gravel, 10 percent soft siltstone gravel; extremely acid (pH 4.2); clear smooth boundary. (Combined thickness of the Bt horizon is 20 to 45 inches thick)
BCt--32 to 45 inches; strong brown (7.5YR 4/6) gravelly silty clay, reddish yellow (7.5YR 6/6) dry; weak medium and coarse subangular blocky structure; hard, firm, very sticky and plastic; few very fine and fine roots; few fine tubular pores; many prominent yellowish red (5YR 4/6) clay films on faces of peds, in pores, and coating rock fragments; 20 percent hard gravel, 40 percent soft siltstone gravel; extremely acid (pH 4.2); abrupt smooth boundary. (0 to 15 inches thick)
Crt--45 inches; highly weathered and fractured siltstone; many distinct yellowish red (5YR 4/6) clay films along rock fractures.
TYPE LOCATION: Douglas County, Oregon, 7 miles south of Loon Lake along the Douglas County line, about 2060 feet north and 850 feet east of the southwest corner of section 18, T. 24 S., R. 9 W. (Latitude 43 degrees, 28 minutes, 49 seconds N, Longitude 123 degrees, 48 minutes, 46 seconds W)
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock ranges from 40 to 60 inches. The mean annual soil temperature at a depth of 20 inches is 47 to 54 degrees F. The soil is usually moist but is dry within the moisture control section for less than 45 consecutive days following the summer solstice. The particle size control section has 35 to 55 percent clay and 0 to 15 percent hard gravel. Organic matter is 5 to 10 percent throughout the upper 10 inches of the solum (estimated).
The A horizon has hue of 10YR or 7.5YR, value of 2 to 4 moist, 3 to 6 dry, and chroma of 2 to 4 moist and dry. It has 5 to 15 percent hard gravel, and 0 to 10 percent soft gravel.
The Bt horizon has value of 3 to 5 moist, 5 to 7 dry, and chroma of 4 to 6 moist and dry. It is clay, silty clay, or silty clay loam. It has 0 to 15 hard gravel, and 0 to 10 percent soft gravel. It is extremely acid to very strongly acid.
The BCt horizon when present, has value of 4 to 6 moist, 5 to 7 dry, and chroma of 4 to 8 moist and dry. It is clay or gravelly silty clay. It has 0 to 20 percent hard gravel, and 0 to 40 percent soft gravel. It is extremely acid to very strongly acid.
COMPETING SERIES: These are the Apt, Hazelcamp (T), McDuff, Peavine, Skookumhouse (T), and Wintley series. Apt and Wintley are greater than 60 inches to bedrock. Hazelcamp, McDuff and Peavine are 20 to 40 inches to bedrock. Skookumhouse has 2.5YR and 5YR hue throughout the Bt.
GEOGRAPHIC SETTING: Absaquil soils are on broad ridges, side slopes, benches, and plateaus. They formed in residuum and colluvium derived from sedimentary rock. Slopes are 3 to 60 percent. Elevations are 100 to 2500 feet. The climate is characterized by warm, wet winters and hot, moist summers. The mean annual temperature is 45 to 53 degrees F. The mean annual precipitation is 55 to 100 inches. The frost free period is 140 to 260 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing McDuff and Peavine soils and the Blachly, Bohannon, Digger, Etelka, Gustin, Honeygrove, Preacher, Remote, Rinearson, and Xanadu soils. McDuff and Peavine soils are on convex side slopes and ridges. Blachly, Honeygrove, and Xanadu soils are very deep, have B horizons with hue of 5YR or 2.5YR, and are on concave side slopes and broad ridges. Bohannon soils are moderately deep and are on convex side slopes and ridges. Digger soils are moderately deep and loamy-skeletal and are on convex or more steeply sloping side slopes. Etelka soils are moderately well drained and on concave side slopes, broad ridges and toeslopes. Gustin soils are somewhat poorly drained and are on concave side slopes and swales. Preacher soils are fine-loamy and are on side slopes and broad ridges. Remote soils are loamy-skeletal and are on convex or more steeply sloping side slopes. Rinearson soils are fine-silty and are on side slopes.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Timber production, recreation, wildlife habitat, and water supply. A few areas are used for pasture. Native vegetation is Douglas fir, western hemlock, western redcedar, grand fir, tanoak, Port Orford cedar with an understory of salal, Pacific rhododendron, evergreen huckleberry, western swordfern, cascade Oregongrape, vine maple, Oregon oxalis, and red huckleberry.
DISTRIBUTION AND EXTENT: Coast Range of southwestern Oregon, MLRA 1. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Coos County, Oregon, 1993. Absaquil was the name of an American Indian that lived in what is now Douglas County, Oregon in the 1850s.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
This soil was previously identified as a bedrock substratum phase of the Orford Series.
Argillic horizon - from 10 to 45 inches. (Bt1, Bt2, Bt3, and BCt horizons)
Base saturation is assumed to be less than 35 percent immediately above bedrock.
More than 0.9 percent organic carbon is assumed in the upper 6 inches of the Bt1 horizon. Based on laboratory data from the type location the 16 to 32 inch zone has 0.6 precent organic carbon.
Particle size control section - from 10 to 30 inches.
ADDITIONAL DATA: Partial laboratory data is available for this soil. Reference sample S820OR019-004 from Douglas County, Oregon, NSSL, Lincoln, NE, 5/83.