LOCATION HELTER OREstablished Series
TAXONOMIC CLASS: Ashy over loamy, glassy over isotic Xeric Vitricryands
TYPICAL PEDON: Helter silt loam, forested. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; litter composed of needles, leaves, wood fragments, moss; matted by mycelia and fine roots. (1/2 to 6 inches thick)
A--1 to 7 inches; very dark grayish brown (10YR 3/2) ashy silt loam, grayish brown (10YR 5/2) dry; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine pores; slightly acid (pH 6.1); abrupt wavy boundary. (0 to 6 inches thick)
Bw1--7 to 16 inches; dark yellowish brown (10YR 4/4) ashy silt loam, very pale brown (10YR 7/4) dry; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine pores; slightly acid (pH 6.2); clear wavy boundary.
Bw2--16 to 34 inches; yellowish brown (10YR 5/6) ashy silt loam, very pale brown (10YR 7/3) dry; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; few very fine and fine roots; common fine tubular pores with reddish staining; slightly acid (pH 6.4); abrupt irregular boundary. (combined thickness of Bw horizon is 12 to 27 inches)
2Bwb1--34 to 41 inches; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; moderate medium and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; few medium, many fine and very fine tubular pores; moderately acid (pH 6.0); clear wavy boundary.
2Bwb2--41 to 49 inches; dark yellowish brown (10YR 4/4) gravelly silt loam, light yellowish brown (10YR 6/4) dry; weak fine subangular blocky structure; hard, firm, slightly sticky and moderately plastic; few fine roots; common very fine tubular pores; 15 percent angular basalt gravel; moderately acid (pH 6.0); gradual smooth boundary. (combined thickness of the 2Bwb horizon is 15 to 43 inches)
2BCb--49 to 60 inches; brown (10YR 4/3) (crushed, variegated and mottled) gravelly silt loam, pale brown (10YR 6/3) dry; weak fine subangular blocky structure; hard, firm, slightly sticky and moderately plastic; many very fine tubular pores; 15 percent basalt gravel; moderately acid (pH 6.0).
TYPE LOCATION: Umatilla County, Oregon; 15 feet WSW of moisture station on Tollgate snow course, in NE 1/4 NE 1/4 sec. 31, T. 4 N., R. 38 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 42 to 47 degrees F., and the mean summer soil temperature is less than 60 degrees F., without an 0 horizon. The soils are usually moist, but are dry for 60 to 70 days during the summer. Depth to bedrock commonly is 60 inches or more, but ranges from 40 to 60 inches in some areas. The thickness of the ash over the buried soil ranges from 20 to 40 inches. The thicker deposits are in concave positions and on north-facing slopes. Krotovinas and disturbance from windthrow are common.
The A horizon has value of 2 through 4 moist and 5 or 6 dry. It has a moist bulk density of 0.75 to 0.85 grams per cubic centimeter.
The Bw horizon has hue of 10YR through 5YR, value of 4 or 5 moist, 6 or 7 dry, and chroma of 3 through 6 moist and dry. It is ashy silt loam and commonly has less than 10 percent clay and less than 25 percent coarser than very fine sand. It has weak structure or is massive.
The 2Bwb horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist. It is silt loam, loam or silty clay loam and has 0 to 30 percent rock fragments. The lower part commonly is gravelly or cobbly and is very cobbly in some pedons that are 40 to 60 inches deep to bedrock. It usually has weak structure, but in some pedons it is massive.
COMPETING SERIES: These are the Almac and Nile series. Almac soils have E and Bs horizons. Nile soils have sandy loam textures in the particle-size control section.
GEOGRAPHIC SETTING: The Helter soils are on gently sloping plateaus and steep north-facing slopes at elevations of 3,500 to 6,500 feet. Slopes are 2 to 65 percent. They formed in volcanic ash and some loess over older buried loess and weathered basalt. The climate is characterized by cold wet winters and cool dry summers. The mean annual precipitation is 22 to 60 inches. The mean annual temperature is 40 to 45 degrees F. The frost-free period is 20 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anatone, Cowsly, Klicker, Snell and Tolo soils. Anatone, Cowsly, Klicker and Snell soils lack the ash overlay, have frigid soil temperature and are on south slopes. Tolo soils are on south slopes and are frigid.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production. Vegetation is grand fir, Douglas fir, subalpine fir, western larch, lodgepole pine and Engleman spruce.
DISTRIBUTION AND EXTENT: Blue Mountains of Oregon and Washington; MLRA 43. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Grant County, Oregon, 1975.
REMARKS: This draft reflects a change in classification form medial over loamy, mixed Entic Cryandepts based on Andisol Order.
Diagnostic horizons and features recognized in this pedon:
ochric epipedon - from 1 to 7 inches (A horizon)
cambic horizon - from 7 to 49inches (Bw1, Bw2, 2Bwb1, and 2Bwb2 horizons)
Andic properties - from surface to 33 inches having more than 60 percent volcanic glass and glass aggragate, more than 0.4 percent acid oxalate extractable aluminum plus one-half iron, and less than 12 percent 15-bar moisture based on an air-dried sample (A, Bw1, Bw2, and 2Bwb1 horizons)
Soil moisture regime is described as xeric when mapped in Grant and Morrow Counties, Oregon within a 22 to 30 inch mean annual precipitation range. When mapped in Umatilla and Union Counties, Oregon within a 35 to 60 inch mean annual precipitation range, these areas would now be considered udic.