LOCATION DESONS OREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, isomesic Typic Palehumults
TYPICAL PEDON: Desons channery clay loam - woodland, on a 12 percent west-facing slope at an elevation of 300 feet. (When described on May 22, 1990 the soil was moist throughout. Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed needles, leaves, twigs and woody materials.
A---0 to 8 inches; reddish brown (5YR 4/4) channery clay loam, yellowish red (5YR 5/6) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, and few medium roots; many very fine tubular pores; 20 percent channers; strongly acid (pH 5.2); clear smooth boundary. (4 to 8 inches thick)
Bt1--8 to 20 inches; reddish brown (5YR 4/4) channery silty clay, yellowish red (5YR 5/6) dry; moderate medium subangular blocky structure; hard, firm, sticky and plastic; many very fine and fine, and few medium roots; many very fine and fine tubular pores; few faint clay films on ped faces and common distinct clay films in pores; 20 percent channers; very strongly acid (pH 5.0); diffuse smooth boundary.
Bt2--20 to 36 inches; reddish brown (5YR 4/4) channery silty clay, yellowish red (5YR 5/6) dry; moderate medium subangular blocky structure; hard, firm, very sticky and very plastic; many very fine and fine, and few medium roots; many very fine and fine tubular pores; common distinct clay films on ped faces and many prominent clay films in pores; 25 percent channers; strongly acid (pH 5.1); diffuse smooth boundary.
Bt3--36 to 46 inches; reddish brown (5YR 4/4) channery silty clay, yellowish red (5YR 5/6) dry; moderate medium and coarse subangular blocky structure; hard, firm, sticky and very plastic; many very fine and fine, and few medium roots; few very fine, and common fine and medium pores; many distinct clay films on ped faces and many prominent clay films in pores; 25 percent channers; strongly acid (pH 5.1); diffuse smooth boundary.
Bt4--46 to 60 inches; yellowish red (5YR 4/6) channery silty clay loam, yellowish red (5YR 5/6) dry; weak medium subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; few very fine, fine, and medium tubular pores; common distinct clay films on ped faces and in pores; 25 percent channers; strongly acid (pH 5.1); clear irregular boundary. (Combined thickness of the Bt horizon is 36 to 52 inches)
C--60 to 72 inches; yellowish brown (10YR 5/6) channery silty clay loam, yellow (10YR 7/6) dry; massive; hard, firm, sticky and plastic; few medium roots; few very fine, fine, and medium tubular pores; 30 percent channers; very strongly acid (pH 5.0).
TYPE LOCATION: Curry County, Oregon; located about 2,500 feet north and 1,500 feet west of the southeast corner of section 35, T. 34 S., R. 13 W., W.M.(Latitude 42 degrees, 35 minutes, 15 seconds N.; Longitude 124 degrees, 19 minutes, 22 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 51 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 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 35 to 50 percent clay and has 15 to 30 percent total rock fragments. Depth to bedrock is greater than 60 inches. The solum is 40 to 60 inches thick. Soil reaction is strongly acid to very strongly acid throughout.
The A horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry and chroma of 4 through 6 moist and dry. It is channery clay loam with 27 to 35 percent clay. It has 15 to 25 percent channers and 0 to 5 percent flagstones.
The Bt horizon has hue of 5YR or 2.5YR, value of 4 or 5 moist, 5 or 6 dry and chroma of 4 through 6 moist and 6 through 8 dry. It is channery silty clay, channery clay, or channery silty clay loam with 35 to 50 percent clay. It has 15 to 25 percent channers and 0 to 5 percent flagstones.
The C horizon has hue of 10YR or 2.5Y, value of 5 or 6 moist, 6 or 7 dry and chroma of 6 through 8 moist and dry. It is channery silty clay loam or channery silty clay with 35 to 45 percent clay. It has 20 to 30 percent channers and 0 to 10 percent flagstones.
COMPETING SERIES: These are the Bentilla, Cunniff, and Klooqueh series. Bentilla soils have redoximorphic features of mottles with chroma of 2 or less at depths of 22 to 30 inches and are moderately well drained. Cunniff soils have an umbric epipedon 10 to 16 inches thick and less than 15 percent angular rock fragments in the particle-size control section. Klooqueh soils have a mean annual soil temperature greater than 54 degrees F.
GEOGRAPHIC SETTING: Desons soils are on stable broad ridgetops and benches of coastal hills and mountains. Slopes are 0 to 30 percent. The soils formed in deep, fine-textured residuum and colluvium derived from schist and phyllite rock types of the Colebrooke Schist Formation. Elevations are 100 to 1000 feet. The climate is 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 75 to 95 inches. The mean annual temperature is 50 to 53 degrees F. The frost-free period is 200 to 270 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Capeblanco, Calfranch, and Watches soils. All of these soils occur on ridgetops, benches, or side slopes of coastal hills and mountains. Capeblanco soils are 20 to 40 inches deep to bedrock and are loamy-skeletal. Calfranch soils are loamy-skeletal. Watches soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Desons soils are used for timber production, homesites, watershed, recreation, and wildlife habitat. The native vegetation is Douglas fir, western hemlock, Sitka spruce, grand fir, Port-Orford cedar, red alder, tanoak, Pacific rhododendron, salal, evergreen huckleberry, red elderberry, salmonberry, western swordfern, western brackenfern, and evergreen violet.
DISTRIBUTION AND EXTENT: Coastal hills and mountains of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995. The name is coined.
REMARKS: Diagnostic horizons and features in this pedon are:
Ochric epipedon.
Argillic horizon - from a depth of 8 to 60 inches (Bt1, Bt2, Bt3, Bt4 horizons).
Particle-size control section - from 8 to 28 inches (Bt1 and part of the Bt2 horizon).
Humults suborder - from 0 to 40 inches, the soil is assumed to have 12 kg/square meter or more organic carbon based on lab data from the associated Calfranch series.
Pale feature - clay distribution in the argillic horizon does not decrease from its maximum amount by 20 percent or more within a depth of 60 inches from the soil surface (Bt1, Bt2, Bt3, Bt4 horizons).