LOCATION AGNESS OR
Established Series
Rev. MHF/RWL
06/2011
AGNESS SERIES
The Agness series consists of very deep, well drained soils formed in colluvium and residuum from schist or phyllite rock types. Agness soils occur in open grassland areas on ridgetops and side slopes of mountains. Slopes are 0 to 60 percent. The mean annual precipitation is about 110 inches and the mean annual temperature is about 49 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Pachic Humudepts
TYPICAL PEDON: Agness channery silt loam - grassland, on a 52 percent south-facing slope at 2,460 feet elevation. (When described on October 24, 1990 the soil was moist throughout. Colors are for moist soil unless otherwise noted.)
A1--0 to 6 inches; very dark grayish brown (10YR 3/2) channery silt loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; 25 percent channers; very strongly acid (pH 4.8); clear smooth boundary.
A2--6 to 14 inches; very dark grayish brown (10YR 3/2) channery silt loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, and common fine roots; many very fine and fine tubular pores; 20 percent channers; very strongly acid (pH 4.8); gradual smooth boundary. (Combined thickness of the A horizon is 12 to 18 inches)
BA--14 to 30 inches; very dark grayish brown (10YR 3/2) channery silt loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; many fine and medium tubular pores; 15 percent channers and 5 percent flagstones; very strongly acid (pH 4.6); gradual smooth boundary. (0 to 16 inches thick)
Bw1--30 to 43 inches; dark grayish brown (10YR 4/2) channery silt loam, light brownish gray (10YR 6/2) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine, and few medium roots; many fine and medium tubular pores; 20 percent channers and 5 percent flagstones; very strongly acid (pH 4.6); gradual smooth boundary.
Bw2--43 to 54 inches; dark grayish brown (10YR 4/2) channery silt loam, light brownish gray (10YR 6/2) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine tubular pores; 20 percent channers and 5 percent flagstones; very strongly acid (pH 4.6); clear smooth boundary.
Bw3--54 to 62 inches; dark grayish brown (10YR 4/2) channery silt loam, light brownish gray (10YR 6/2) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine tubular pores; 20 percent channers and 10 percent flagstones; very strongly acid (pH 4.6); clear wavy boundary. (Combined thickness of the Bw horizon is 30 to 36 inches)
C--62 to 72 inches; light olive brown (2.5Y 5/3) very flaggy silty clay loam, pale yellow (2.5Y 7/3) dry; massive; slightly hard, firm, slightly sticky and slightly plastic; few medium tubular pores; 20 percent channers and 15 percent flagstones; very strongly acid (pH 4.6).
TYPE LOCATION: Curry County, Oregon; about 1,320 feet south and 990 feet east of the northwest corner of section 25, T. 35 S., R. 13 W. (Latitude 42 degrees, 31 minutes, 17 seconds N.; Longitude 124 degrees, 11 minutes, 58 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 54 degrees F. The soils are usually moist but 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 18 to 25 percent clay and has 15 to 30 percent total rock fragments. Depth to bedrock is greater than 60 inches. The umbric epipedon is 20 to 30 inches thick, and includes the upper portion of the Bw horizon.
The A horizon has value of 2 or 3 moist, 3 to 5 dry and chroma of 1 or 2 moist and dry. It is channery silt loam averaging 15 to 25 percent clay. It has 15 to 30 percent channers.
The Bw horizon has value of 3 or 4 moist, 4 through 6 dry and chroma of 2 or 3 moist and dry. It is channery silt loam or channery loam averaging 18 to 25 percent clay. It has 15 to 20 percent channers and 0 to 10 percent flagstones.
The C horizon has hue of 10YR or 2.5Y, value of 4 or 5 moist, 6 or 7 dry and chroma of 2 or 3 moist and dry. It is very flaggy silty clay loam, very channery silty clay loam, or very flaggy clay loam averaging 27 to 35 percent clay. It has 20 to 30 percent channers, 15 to 20 percent flagstones, and 0 to 5 percent stones.
COMPETING SERIES: These are the
Quailprairie and
Sixes series. Quailprairie soils have particle-size control sections dominated by clay loam or heavy loam textures averaging 20 to 35 percent clay, and have angular-shaped rock fragments in the solum. In addition, Sixes soils are 20 to 40 inches deep to bedrock.
GEOGRAPHIC SETTING: Agness soils occur in open grassland areas on metastable ridgetops and south-facing side slopes of mountains. Slopes are 0 to 60 percent. The soils formed in colluvium and residuum derived from schist or phyllite rock types of the Colebrooke Schist Formation. Elevations are 1,000 to 3,000 feet. The climate is characterized by warm, wet winters and hot, moist summers. The mean annual precipitation is 90 to 130 inches. The mean annual temperature is 45 to 53 degrees F. The frost-free period is 120 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Barkshanty,
Deadline,
Edson,
Goldbeach,
Irma,
Nailkeg, and the competing
Sixes soils. All of these soils occur on broad ridgetops or side slopes of mountains. Barkshanty and Edson soils have argillic horizons. Deadline soils are 40 to 60 inches deep to bedrock and are loamy-skeletal. Irma soils are greater than 60 inches deep to bedrock and have an ochric epipedon. Nailkeg soils are 20 to 40 inches deep to bedrock and are loamy-skeletal. Goldbeach soils are 10 to 20 inches deep to bedrock and are loamy-skeletal. Sixes soils are 20 to 40 inches deep to bedrock. Goldbeach and Sixes soils occur in open grassland areas on ridgetops and south-facing side slopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Agness soils are used for wildlife habitat and recreation. The vegetation is brome, bluegrass, bristly dogtail, California oatgrass, bentgrass, dock, lupine, western brackenfern, a few widely scattered Oregon white oak and canyon live oak, woodrush, sedges, and rushes.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon; 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from the surface to a depth of 30 inches (A1, A2, BA horizons).
Cambic horizon - from a depth of 30 to 62 inches (Bw1, Bw2, Bw3 horizons).
Pachic subgroup - based on dark colors to a depth of 30 inches.
Particle-size control section - from 10 to 40 inches (part of the A2 horizon, BA, and part of the Bw1 horizon).
National Cooperative Soil Survey
U.S.A.