LOCATION PISGASPRING OR
Tentative Series
IRD. JRD/KLS
02/2025
PISGASPRING SERIES
Landscape--mountains
Landform--mountain slopes
Slope--10 to 70 percent
Parent material--volcanic ash over colluvium derived from basalt, andesite or other hard volcanic rocks
Mean annual precipitation--910 mm
Mean annual air temperature--3 degrees C
Depth class--deep and very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Ashy over loamy-skeletal, amorphic over isotic Alfic Vitricryands
TYPICAL PEDON: Pisgaspring gravelly ashy sandy loam - woodland, on a 15 percent, northeast-facing slope at an elevation of 1985 m. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 cm; slightly decomposed needles and litter
A1--1 to 5 cm; black (10YR 2/1) gravelly ashy sandy loam, very dark gray (10YR 3/1) dry; weak, thin and medium platy structure; very soft, very friable, nonsticky and nonplastic; many very fine, and fine roots throughout; common very fine and fine irregular pores; 15 percent gravel, 5 percent cobbles and 2 percent stones; moderately acid (pH 5 8); abrupt wavy boundary. (1.5 to 3 inches thick)
A2--5 to 23 cm; very dark brown (10YR 2/2) gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) dry; weak thin and medium platy structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots throughout; common very fine irregular pores; 15 percent gravel, 5 percent cobbles, and 2 percent stones; moderately acid (pH 6.0); clear wavy boundary. (4 to 8 inches thick)
A3--23 to 38 cm; dark brown (10YR 3/3) gravelly ashy sandy loam, brown (10YR 4/3) dry; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine through coarse roots throughout; few fine irregular pores; 15 percent gravel, 5 percent cobbles, and 2 percent stones; moderately acid (pH 5.8); gradual wavy boundary. (5 to 8 inches thick)
Bt1--38 to 56 cm; dark yellowish brown (10YR 3/4) very cobbly ashy sandy loam, brown (10YR 4/3) dry; weak fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine through coarse roots throughout; common very fine and fine irregular pores; few faint clay films bridging sand grains; 15 percent gravel, 30 percent cobbles, and 2 percent stones; moderately acid (pH 5.8); clear wavy boundary. (5 to 10 inches thick)
2Bt2--56 to 86 cm; dark brown (10YR 3/3) very gravelly sandy loam, brown (10YR 4/3) dry; moderate fine and medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; few very fine through medium roots throughout; few very fine and fine irregular pores; few faint clay films bridging sand grains; 30 percent gravel and 10 percent cobbles; moderately acid (pH 5.8); gradual wavy boundary. (10 to 14 inches thick)
2Bt3--86 to 119 cm; dark brown (10YR 3/3) extremely gravelly loam, brown (10YR 4/3) dry; strong fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine through medium roots throughout; few very fine and fine irregular pores; many faint clay films on ped and rock faces; 50 percent gravel and 10 percent cobbles; moderately acid (pH 5.6); abrupt wavy boundary. (10 to 16 inches thick)
3R--119 to 160 cm; slightly weathered to indurated andesitic basalt bedrock
TYPE LOCATION: Wheeler County, Oregon, about 2.4 km east of Mt Pisgah, off Ochoco National Forest road 2630, about 30 m west of the junction with the 2630-150 road; NE of the SW of section 9, T.13S., R.21E.; latitude 44.4579220, longitude -120.2051530, WGS84 Datum (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--1 to 5 degrees C
Soil moisture--dry for less than 30 consecutive days during the four months following the summer solstice
Mollic epipedon--15 to 40 cm thick
Depth to lithic contact--greater than 100 cm
Estimated properties of layers with andic soil properties
*Andic Soil Properties--upper boundary at mineral soil surface, 36 to 86 cm thick
*0.2 to 2.0 mm fraction--60 to 80 percent of fine earth
*P Retention--40 to 70 percent
*Acid oxalate Al + 1/2Fe--0.4 to 2.0 percent
*Volcanic glass content in 0.2 to 2.0 mm fraction--30 to 50 percent
*Water content at 1500kPa (air dry)--10 to 12 percent
Particle Size Control Section (upper 100cm below mineral soil surface)
Upper part (ashy)--36 to 86 cm thick
*Clay content--5 to 18 percent
*Total rock fragments (weighted average)--5 to 35 percent
Lower part (loamy-skeletal)--14 to 80 cm thick
*Clay content--18 to 30 percent
*Total rock fragments (weighted average)--35 to 80 percent
A horizons
*Hue--10YR moist or dry
*Value--3 to 6 dry, 2 to 3 moist
*Chroma--2 to 4 moist or dry
*Fine earth texture--sandy loam
*Clay content--5 to 15 percent
*Sand content--55 to 75 percent
*Organic matter content--1 to 4 percent
*Total rock fragments--5 to 30 percent
*Gravel content--5 to 15 percent
*Cobble content--0 to 10 percent
*Stone content--0 to 5 percent
*Reaction--moderately acid
*Thickness--25 to 60 cm
Bt1 horizon
*Hue--10YR moist or dry
*Value--3 to 6 dry, 3 or 4 moist
*Chroma--3 or 4 moist or dry
*Fine earth texture--sandy loam, loam
*Clay content--12 to 25 percent
*Sand content--40 to 65 percent
*Organic matter content--0.5 to 2
*Total rock fragments--30 to 65 percent
*Gravel content--10 to 45 percent
*Cobble content--20 to 60 percent
*Stone content--0 to 15 percent
*Reaction--moderately acid
*Thickness--0 to 25 cm
2Bt horizons
*Hue--10YR or 7.5YR
*Value--4 to 6 dry, 3 or 4 moist
*Chroma--2 to 4 moist or dry
*Fine earth texture--sandy loam, loam, sandy clay loam
*Clay content--15 to 35 percent
*Sand content--40 to 65
*Organic matter content--0.5 to 1 percent
*Total rock fragments--35 to 70 percent
*Gravel content--40 to 55 percent
*Cobble content--5 to 15 percent
*Stone or boulder content--5 to 15 percent
*Reaction--moderately to slightly acid
COMPETING SERIES:
Bott--greater than 150 cm to restrictive feature; dry for greater than 30 days following the summer solstice.
Tyeecreek--greater than 150 cm to restrictive feature; ashy part is 36 to 43 cm thick and is silt loam with 3 to 8 percent clay
Webbridge--100 to 150 cm to lithic contact; upper ashy part is silt loams with 25 to 45 percent glass and 0 to 25 percent gravels
GEOGRAPHIC SETTING:
Elevation--1650 to 2150 m
Aspect--typically north and east
Climate--cold, wet winters and cool, moist summers
Mean annual precipitation--500 to 910 mm
Mean annual air temperature--2 to 6 degrees C
Frost-free period--10 to 45 days
Lithology--volcanic ash derived from Mt Mazama over residuum and colluvium derived from Columbia River Basalts and/or tuffs and andesites associated with the Clarno Formation.
GEOGRAPHICALLY ASSOCIATED SOILS:
Pisgasha--occur on mountain sideslopes; have greater than 100cm of andic soil properties
Wineburger--occur on benches and mountain side slopes; 100 to 150 cm to bedrock; xeric moisture regime
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--well drained
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--High in the upper ashy part, moderately high in the lower part
USE AND VEGETATION:
Use--timber production, wildlife habitat, recreation
Potential native vegetation--Lodgepole pine, subalpine fir, grand fir, Douglas fir, grouse huckleberry, elk sedge
Typical plant association--CAG111 Subalpine fir/Elk sedge; CES411 Subalpine fir/grouse huckleberry; Plant Associations of the Blue and Ochoco Mountains; USDA Forest Service
DISTRIBUTION AND EXTENT: Central Oregon, Ochoco Mountains (southwest Blue Mountains, MLRA 10. The soil is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Ochoco National Forest, Wheeler County, Oregon, 2015; The name is coined from Pisgah Springs Creek on the Pisgah USGS Quadrangle.
REMARKS:
Diagnostic horizon and features recognized in this pedon are
*Mollic epipedon--1 to 38 cm
*Andic soil properties--from the mineral soil surface to 86 cm
*Argillic horizon--87 to 119 cm
National Cooperative Soil Survey
U.S.A.