LOCATION GUNN WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Haploxeralfs
TYPICAL PEDON: Gunn loam - forested on a 3 percent southeast-facing slope at an elevation of 1,780 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 6 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and few medium roots; many fine interstitial pores; slightly acid (pH 6.2); abrupt smooth boundary.
A2--6 to 10 inches; light brown (7.5YR 6/3) loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and few coarse roots; common fine tubular pores; moderately acid (pH 6.0); clear wavy boundary. (Combined thickness of the A horizon is 7 to 14 inches)
BA--10 to 18 inches; light brown (7.5YR 6/4) loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular block structure; hard, friable, slightly sticky and slightly plastic; common very fine and few medium roots; few faint clay films on faces of peds; slightly acid (pH 6.2); clear wavy boundary.
Bt1--18 to 34 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine and few fine roots; common fine tubular and common medium tubular pores; common distinct clay films on faces of peds; slightly acid (pH 6.2); gradual wavy boundary.
Bt2--34 to 45 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine roots; many fine tubular and many medium tubular pores; common distinct clay films on faces of peds; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the Bt horizon is 15 to 30 inches.)
BCt--45 to 66 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; few very fine roots between peds; many fine tubular and many medium tubular pores; many distinct clay films on faces of peds; slightly acid (pH 6.2). (10 to 30 inches thick)
TYPE LOCATION: Klickitat County, Washington; 2,500 feet north and 2,600 feet east of the southwest corner of section 25, T. 5N., R. 14 E. Latitude 45 degrees, 53minutes, 22 seconds N. and Longitude 120 degrees, 59 minutes 51 seconds W. NAD27.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 50 degrees F. The soil moisture control section is usually moist, but is dry in all parts for 90 to 105 consecutive days. The solum is 40 to 60 inches or more. Rock fragments in the control section average from 0 to 10 percent. Some pedons have a stony surface layer. The particle-size control section averages 22 to 32 percent clay. Reaction is slightly acid to moderately acid throughout.
The A horizon has hue of 7.5YR or 5YR, value of 4 to 6 dry, 3 or 4 moist and chroma of 2 to 6 dry or moist.
The Bt horizon has hue of 7.5YR or 5YR, value of 5 or 6 dry, 3 or 4 moist and chroma of 2 to 4 dry and moist. Texture is loam or clay loam.
The BCt horizon has hue of 7.5YR or 5YR, value 5 or 6 dry, 3 or 4 moist, and chroma of 4 to 6 dry. Rock fragments range from 0 to 10 percent gravel and 0 to 45 percent paragravel.
COMPETING SERIES: These are the Beal, Boardburn, Boomer, Casabonne, Cherryhill, Cle Elum, Cohasset, Crozier, Dalig, Fives, Fong, Fordcreek (T), Hood, Latourell, Lettia, Norling, Para, Pishpishee, Rosehaven, Sanhedrin, Tigit, Varelum and Wohly series. Beal soils are 30 to 40 inches to low chroma redox depletions, are 15 to 25 inches to redox concentrations, and have hue in the Bt horizon of 10YR to 5Y. Boardburn, Fong and Fordcreek soils have a paralithic contact at 40 to 60 inches. Boomer soils are 40 to 80 inches to a paralithic contact and are dry for more than 105 consecutive days. Casabonne soils are 40 to 60 inches to a lithic contact and have a mean annual soil temperature of 54 to 59 degrees F. Cherryhill soils are 40 to 60 inches to a paralithic contact and are dry for 60 to 80 consecutive days. Cle Elum, Crozier, Tigit and Wohly soils have a paralithic or a lithic contact at a depth of 20 to 40 inches. Cohasset soils are 40 to 80 inches to a paralithic contact and are dry for more than 105 consecutive days. Dalig soils are dry for 60 to 75 consecutive days and lack moderate structure and distinct clay films throughout the argillic horizon. Fives soils are dry for 45 to 60 consecutive days, are 10YR to 2.5Y hue in the Bt, and are strongly acid below a depth of about 17 inches. Hood soils are dry for 60 to 75 consecutive days. Latourell soils are dry for 45 to 80 consecutive days, are 45 to 60 inches to a sandy loam discontinuity with 25 to 60 percent gravel. Lettia soils are dry for 45 to 60 consecutive days and have a paralithic contact at 40 to 60 inches. Norling soils have a paralithic contact at 20 to 40 inches. Para soils are dry for 45 to 60 consecutive days. Pishpishee soils have 10 to 30 percent rock fragments in the particle-size control section. Rosehaven soils are dry for 60 to 80 consecutive days and have a mean annual soil temperature of 52 to 57 degrees F. Sanhedrin soils have a lithic contact at 40 to 60 inches and have a mean annual soil temperature of 50 to 58 degrees F. Varelum soils are dry for 60 to 75 consecutive days and are 40 to more than 60 inches to a paralithic contact.
GEOGRAPHIC SETTING: Gunn soils are on plateaus, benches, side slopes and ridgetops at elevations of 600 to 3,800 feet. Slopes are 0 to 65 percent. The soils formed in loess and residuum weathered from basalt. Summers are warm and dry and winters are cool and moist. The mean annual precipitation is 15 to 25 inches. The average January temperature is 28 degrees F. and average July temperature is 66 degrees F. The mean annual temperature is 46 to 49 degrees F. The frost-free season is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goldendale, Itat, Kiakus, Leidl, Munset, Quiden, and Wahoo soils and the competing Dalig soils. Itat soils on plateaus, Leidl soils on canyon side slopes and Wahoo soils on canyon breaks are loamy-skeletal and lack an argillic horizon. Kiakus soils on plateaus and Munset soils in depressions have bedrock at a depth of 20 to 40 inches. Quiden soils on plateaus lack an argillic horizon. Goldendale soils on plateaus have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for timber production, livestock grazing, wildlife habitat and cropland. Principal farm crops are wheat, alfalfa, and pasture. Native vegetation is predominantly ponderosa pine and Oregon white oak with scattered Douglas-fir and an understory of redstem ceanothus, snowbrush ceanothus, pinemat manzanita, squawcarpet, elk sedge, Oregon-grape, Idaho fescue, bluebunch wheatgrass, antelope bitterbrush, poison-oak, yarrow and lupine.
DISTRIBUTION AND EXTENT: Central Klickitat County, Washington; MLRA 6. The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Klickitat County, Washington, 2003.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 10 inches
Argillic horizon - 18 to 45 inches.
Particle-size control section - 18 to 38 inches.