LOCATION FOURTHCREEK OR
Established Series
IRD. JLW/DAL/RWL/KMS
01/2019
FOURTHCREEK SERIES
Landscape--mountains
Landform- mountain slopes
Slope--15 to 30 percent
Parent material--thick mantle of volcanic ash mixed with loess over residuum derived from granite and granodiorite
Mean annual precipitation--about 770 mm
Mean annual air temperature--about 4 degrees C
Depth class--moderately deep to paralithic contact
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic, frigid Typic Vitrixerands
TYPICAL PEDON: Fourthcreek ashy silt loam in an area of woodland, on a 15-percent, convex, northeast-facing slope at an elevation of 1463 m
Oi--0 to 3 cm; needles
Oe--3 to 5 cm; decomposed organic matter
A--5 to 10 cm; ashy silt loam, grayish brown (10YR 5/2) dry, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to weak very fine and fine subangular blocky; soft, very friable, nonsticky and nonplastic; few fine and common medium roots; common fine irregular pores; slightly acid (pH 6.5); clear wavy boundary
Bw1--10 to 28 cm; ashy silt loam, very pale brown (10YR 7/4) dry, yellowish brown (10YR 5/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and medium and few coarse roots; few fine irregular pores; slightly acid (pH 6.5); clear wavy boundary
Bw2--28 to 53 cm; ashy silt loam, very pale brown (10YR 7/4) dry, yellowish brown (10YR 5/6) moist; massive parting to weak very fine subangular blocky structure; loose, very friable, nonsticky and nonplastic; common fine, many medium, and few coarse roots; few fine tubular pores; slightly acid (pH 6.5); clear wavy boundary
2EBb--53 to 71 cm; sandy loam, light gray (2.5Y 7/2) dry, olive brown (2.5Y 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine and medium roots; few fine tubular pores; slightly acid (pH 6.5); gradual smooth boundary
2Bwb--71 to 97 cm; sandy loam, light gray (2.5Y 7/2) dry, olive brown (2.5Y 4/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; few fine roots; 5 percent gravel; slightly acid (pH 6.5); clear smooth boundary
2Cr--97 to 104 cm; granitic grus
2R--104 cm; hard granodiorite
TYPE LOCATION: Baker County, Oregon; in the NE1/4SW1/4SW1/4 of section 16, T. 10 S., R. 37 E.; Sumpter U.S. Geological Survey quadrangle; longitude -118.1915194, latitude 44.6893493, datum WGS 84 (coordinates estimated from PLSS details)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5 to 6 degrees C
Mean summer soil temperature--9 to 11 degrees C
Mean winter soil temperature--1 to 2 degrees C
Soil moisture control section--dry 45 to 60 days in summer
Depth to paralithic contact--50 to 100 cm
Depth to lithic contact--60 to 110 cm
Thickness of ash-influenced layers--40 to 75 cm
Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + 1/2 Fe--1.0 to 2.5 percent
*0.02- to 2.0-mm fraction--40 to 60 percent
*Glass content in 0.02- to 2.0-mm fraction--60 to 90 percent
*1/3-bar bulk density--0.65 to 1.0 g/cm3
*Phosphate retention--40 to 90 percent
*15-bar water retention--5 to 12 percent (dried samples)
*8 x Si plus 2 x Fe--5 to 12 percent
Particle-size control section
*Ashy upper part--40 to 50 cm thick; 3 to 8 percent clay (weighted average); 0 percent rock fragments
*Loamy lower part--10 to 50 cm thick; 1 to 10 percent clay (weighted average); 3 to 25 percent rock fragments (weighted average)
A horizon
Moist color--10YR 3/2, 10YR 3/4, 10YR 4/2, 10YR 4/3, 10YR 5/2
Dry color--10YR 5/2, 10YR 5/4, 10YR 6/2, 10YR 6/4, 10YR 7/2
Fine-earth texture--ashy sandy loam, ashy silt loam
Clay content--4 to 10 percent
Sand content--35 to 65 percent
Organic matter content--2 to 6 percent
Reaction--5.6 to 7.3
Thickness--5 to 25 cm
Bw1 horizon
Moist color--10YR 4/4, 10YR 5/3, 10YR 5/4
Dry color--10YR 6/4, 10YR 7/2, 10YR 7/3, 10YR 7/4
Fine-earth texture--ashy sandy loam, ashy silt loam
Clay content--3 to 10 percent
Sand content--35 to 65 percent
Organic matter content--1 to 2 percent
Reaction--5.6 to 6.5
Thickness--8 to 30 cm
Bw2 horizon
Moist color--10YR 5/3, 10YR 5/4, 10YR 5/6
Dry color--10YR 7/3, 10YR 7/4, 10YR 8/3, 10YR 8/4
Fine-earth texture--ashy sandy loam, ashy silt loam
Clay content--2 to 3 percent
Sand content--45 to 65 percent
Organic matter content--0.5 to 1.5 percent
Reaction--5.6 to 7.3
Thickness--5 to 25 cm
2EBb horizon
Moist color--2.5Y 4/4, 2.5Y 5/2, 10YR 3/3, 10YR 5/3
Dry color--2.5Y 7/2, 10YR 5/3, 10YR 7/3
Fine-earth texture--loamy sand, sandy loam
Clay content--2 to 10 percent
Sand content--60 to 85 percent
Organic matter content--1 to 2 percent
Total rock fragment content--0 to 25 percent
Gravel content--0 to 25 percent
Cobble content--0 to 5 percent
Reaction--5.6 to 7.3
Thickness--13 to 20 cm
2Bwb horizon
Moist color--2.5Y 4/4, 2.5Y 5/2, 10YR 5/2
Dry color--2.5Y 7/2
Fine-earth texture--loamy sand, sandy loam
Clay content--0 to 4 percent
Sand content--60 to 80 percent
Organic matter content--0.5 to 1.5 percent
Total rock fragment content--5 to 20 percent
Gravel content--5 to 15 percent
Cobble content--0 to 10 percent
Reaction--5.6 to 7.3
Thickness--13 to 40
2Cr horizon
Thickness--7 to 20 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--1450 to 1840 m
Climate--cool, wet winters; warm, moist summers
Mean annual precipitation--610 to 930 mm
Mean annual air temperature--3 to 5 degrees C
Frost-free period--35 to 65 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Roundmeadow--on steeper slopes; 50 to 100 cm to paralithic contact; ash layer less than 35 cm thick
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high
USE AND VEGETATION:
Use--timber production, watershed, recreation, wildlife habitat
Native vegetation--grand fir, Douglas-fir, western larch, Engelmann spruce, big huckleberry, pathfinder, pinegrass, heartleaf arnica, smallflower miterwort, largeleaf sandwort, sidebells wintergreen, baldhip rose, western meadow-rue, Columbia brome, elk sedge, Ross' sedge, woodland strawberry, sweetcicely, currant, white spirea
U.S. Forest Service plant association--dominantly ABGR/VAME; may include PICO(ABGR)/VASC and ABGR/VASC
DISTRIBUTION AND EXTENT: Blue Mountains of northeastern Oregon; MLRA 43C; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa-Whitman National Forest, Oregon; 2018
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Ochric epipedon
*Cambic horizon--zone from 10 to 97 cm
*Volcanic glass--zone from 5 to 53 cm
*Andic soil properties--zone from 5 to 53 cm
*Particle-size control section--zone from 5 to 97 cm
*Depth to paralithic contact--97 cm
*Depth to lithic contact--104 cm
National Cooperative Soil Survey
U.S.A.