LOCATION BROMAS WAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, isotic Haploxerandic Haplocryepts
TYPICAL PEDON: Bromas ashy sandy loam, forestland on a 42 percent north facing slope at an elevation of 4,550 feet, under a Douglas-fir, Engelmann spruce, lodgepole pine canopy. (Colors are for dry soil unless otherwise stated. When described on October 6, 1992, the soil was dry throughout. All textures are apparent field textures.)
Oe--0 to 2 inches; moderately decomposed organic matter.
A--2 to 6 inches; pale brown (10YR 6/3) ashy sandy loam, dark yellowish brown (10YR 3/4) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic and weakly smeary; many fine and very fine and common medium roots; common fine irregular pores; 10 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (0 to 5 inches thick)
Bw--6 to 14 inches; light yellowish brown (10YR 6/4) cobbly ashy sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; many fine and very fine, common medium, and few coarse roots; common fine irregular pores; 15 percent gravel and 10 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (6 to 10 inches thick)
2C1--14 to 33 inches; light gray (10YR 7/2) very gravelly loamy sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; 30 percent gravel, 15 percent cobbles, and 2 percent stones; slightly acid (pH 6.4); gradual wavy boundary. (12 to 25 inches thick)
3C2--33 to 39 inches; light gray (2.5Y 7/2) very gravelly sandy loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common medium and few fine roots; common irregular pores; 35 percent gravel, 10 percent cobbles, and 2 percent stones; neutral (pH 6.6); gradual wavy boundary. (0 to 5 inches thick)
3Cr--39 inches; weathered gneiss.
TYPE LOCATION: Okanogan County, Washington; about 15 miles north of the town of Winthrop, Washington, and about 1.5 miles northwest of South Twentymile Peak on the Okanogan National Forest. (Latitude 48 degrees, 40 minutes, 52 seconds N., Longitude 120 degrees, 05 minutes, 00 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 37 to 43 degrees F. The mean summer soil temperature ranges from 42 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 45 to 60 consecutive days following the summer solstice. Depth to a paralithic contact is 20 to 40 inches. Thickness of the volcanic ash mantle ranges from 7 to 14 inches and has an estimated moist bulk density of 0.75 to 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. The 10 to 40 inch particle-size control section averages 35 to 55 percent rock fragments.
The A horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry or moist.
The Bw horizon has value of 6 or 7 dry. It is gravelly or cobbly ashy sandy loam with 10 to 20 gravel and 5 to 10 percent cobbles. Reaction is slightly acid to neutral.
The 2C horizon has hue of 10YR or 2.5Y, value of 7 or 8 dry, 5 or 6 moist, and chroma of 2 through 4 dry or moist. It is very gravelly or very cobbly loamy sand with 25 to 45 percent gravel, 10 to 20 percent cobbles, and 0 to 5 percent stones. Reaction ranges from moderately acid to neutral.
The 3C horizon is a relatively thin horizon and is absent in some pedons. It has value of 6 or 7 dry, 5 to 6 moist, and chroma of 2 to 4 dry or moist.
COMPETING SERIES: This is the Sitdown series. Sitdown soils are more than 40 inches deep.
GEOGRAPHIC SETTING: Bromas soils are on shoulder slopes and back slopes of mountains and have slopes of 35 to 65 percent. These soils formed in residuum and colluvium from granite or gneiss with a mantle of volcanic ash. Elevations range from 4,200 to 6,400 feet. The climate is characterized by cold, wet winters and cool, dry summers. The average annual precipitation ranges from 25 to 35 inches. The average January temperature ranges from 18 to 22 degrees F, average July temperature ranges from 52 to 58 degrees F, and the average annual air temperature ranges from 35 to 41 degrees F. The frost-free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brevco, Kiehl, Sitdown, and Wapal soils. Brevco soils are on shoulders and back slopes of mountains and are frigid. Kiehl soils are on back slopes of mountains and are frigid. Sitdown soils are on back slopes of mountains and are deeper than 40 inches to bedrock. Wapal soils are on southerly facing back slopes of mountains and are frigid.
DRAINAGE AND PERMEABILITY: Well drained, rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Timber production, wildlife habitat, watershed, and recreation. Native vegetation is Douglas-fir, Engelmann spruce, lodgepole pine, dwarf huckleberry, grouse blueberry, and Sitka alder.
DISTRIBUTION AND EXTENT: Okanogan County, Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan County, Washington, Okanogan National Forest, 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon, a cambic horizon from 6 to 14 inches, a mantle of volcanic ash from 2 to 14 inches that meets andic soil properties, and a paralithic contact of weathered gneiss bedrock at 39 inches. Xeric soil moisture regime.
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.