LOCATION GATEWALL WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Haploxerandic Haplocryepts
TYPICAL PEDON: Gatewall ashy sandy loam, on a northwest facing 18 percent slope at 4,600 feet elevation in a subalpine fir, Engelmann spruce, Douglas-fir forest. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles and twigs; abrupt smooth boundary. (1 to 3 inches thick)
A--1 to 5 inches; pale brown (10YR 6/3) ashy sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic and moderately smeary; many very fine and fine, and few medium and coarse roots; common very fine and fine pores; 5 percent pebbles; slightly acid (pH 6.1); clear smooth boundary. (1 to 5 inches thick)
Bw--5 to 14 inches; light yellowish brown (10YR 6/4) ashy sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky, nonpalstic and moderately smeary; common very fine and fine, and few medium and coarse roots; common very fine and fine pores; 10 percent pebbles; slightly acid (pH 6.3); clear smooth boundary. (6 to 10 inches thick)
2BC--14 to 25 inches; light brownish gray (10YR 6/2) very gravelly sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine, and few medium roots; common very fine and fine pores; 35 percent pebbles and 5 percent cobbles; slightly acid (pH 6.3); gradual wavy boundary. (10 to 15 inches thick)
2Cd1--25 to 35 inches; light brownish gray (10YR 6/2) very gravelly sandy loam, dark grayish brown (10YR 4/2) moist; massive; hard, friable, nonsticky and nonplastic; few very fine and fine roots; few fine pores; 35 percent pebbles and 5 percent cobbles; neutral (pH 6.6); clear wavy boundary. (8 to 12 inches thick)
2Cd2--35 to 40 inches; pale brown (10YR 6/3) very gravelly sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and slightly plastic; few very fine and fine roots; few very fine pores; 30 percent pebbles and 5 percent cobbles; neutral (pH 6.6); clear wavy boundary. (5 to 10 inches thick)
3Cd--40 to 61 inches; brown (7.5YR 5/2) very gravelly sandy loam, brown (7.5YR 4/2) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine pores; 30 percent pebbles and 5 percent cobbles; neutral (pH 6.6).
TYPE LOCATION: Okanogan County, Washington; about 3.5 miles northwest of Mazama, WA., about 1,900 feet west and 500 feet north of the southeast corner of section 11, T. 36 N., R. 19 E. (Latitude 48 degrees 37' 49"N., Longitude 120 degrees 25' 58"W.)
RANGE IN CHARACTERISTICS: The average annual soil temperature is 37 to 41 degrees F. Average 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. Thickness of the volcanic ash is 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 8 to 12 percent for air dried samples. Depth to compact till ranges from 20 to 30 inches. The particle-size control section averages 35 to 50 percent rock fragments and 8 to 15 percent clay.
The A horizon has value of 3 or 4 moist and chroma of 3 or 4 dry or moist.
The Bw horizon has chroma of 3 or 4 dry or moist. It is sandy loam or gravelly sandy loam. It has 10 to 20 percent pebbles.
The 2BC horizon has value of 3 or 4 moist and chroma of 2 to 4 dry or moist. It is gravelly sandy loam, very gravelly sandy loam or very cobbly sandy loam. It has 20 to 35 percent pebbles and 5 to 15 percent cobbles.
The 2Cd horizons have hues of 7.5YR, 2.5Y or 10YR, value of 4 or 5 moist, and chroma of 2 or 3 dry or moist. It is very gravelly sandy loam or very cobbly sandy loam. It has 30 to 40 percent pebbles and 10 to 20 percent cobbles. Reaction ranges from slightly acid to neutral.
The 3Cd horizon has hues of 5YR, 7.5YR and 10YR, values of 5 or 6 dry, 4 or 5 moist and chromas of 2 or 3 dry or moist. It is very gravelly sandy loam or very cobbly sandy loam. It has 25 to 35 percent pebbles and 10 to 20 percent cobbles. Reaction ranges from slightly acid to neutral.
COMPETING SERIES: These are the Buhrig, Devore, Finney, Holloway, Hun, Moses, Myerscreek, Otwin, Petty, Phillcher, Prouty, Rumsey, Surgh, Venson, and Waldbillig series. The Buhrig, Devore, Otwin and Venson soils are 20 to 40 inches to lithic contact. The Moses and Prouty soils are 20 to 40 inches to paralithic contact. Phillcher soils have a mean annual soil temperature of 35 to 38 degrees F and are dry for less than 45 consecutive days. Holloway soils are loams and silt loams throughout. Hun soils are loamy sand or coarse sand in the fine earth fraction of the 2C horizon. Myerscreek soils have 2 to 6 percent clay in the particle-size control section. Petty soils have 20 to 30 percent clay in the particle-size control section. Rumsey soils are over 60 inches deep to bedrock. Finney and Surgh soils lack a 2Cd horizon and have bedrock at 40 to 60 inches. Waldbillig soils have lamellae and a very hard 2E and Bt horizon.
GEOGRAPHIC SETTING: Gatewall soils are on toeslopes, footslopes and backslopes of mountains and have slopes of 15 to 65 percent. These soils formed in compact glacial till from sedimentary and volcanic sources with a mantle of volcanic ash. Elevations are 4,200 to 5,900 feet. Precipitation is 25 to 35 inches. The climate is characterized by cool, dry summers and cold, wet winters. The average January temperature ranges from 18 to 22 degrees F., and the average July temperature ranges from 52 to 58 degrees F. Average annual temperature is 37 to 41 degrees F. Frost-free season is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Longort and Volmont soils. Longort soils are frigid and usually are on south aspects. Volmont soils are 20 to 40 inches to bedrock on backslopes, shoulders and ridges of mountains.
DRAINAGE AND PERMEABILITY: Well drained, medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat, watershed, and recreation. Native vegetation is subalpine fir, Engelmann spruce, Douglas-fir and some western redcedar with an understory of whortleberry, blue huckleberry, pinegrass, silky lupine, northwestern sedge, western princes pine, mountainlover and some cascades azalea.
DISTRIBUTION AND EXTENT: Northcentral Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan National Forest, Okanogan County, Washington, 2005.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon
Cambic horizon - 5 to 14 inches formed in volcanic ash
PSCS - zone from 11 to 25 inches (part of the Bw, 2BC horizons)
Densic materials are at 24 inches
Andic soil properties from 1 to 14 inches
Depths to diagnostic horizons and other features are measured from the top if the first mineral horizon.
Further investigation is needed as to a udic soil moisture regime.