LOCATION BOLLETTO OR
Inactive Series
Rev. RJO/JLW/DAL
12/2017
BOLLETTO SERIES
The Bolletto series consists of moderately deep, well-drained soils on mountain backslopes. Bolletto soils formed in colluvium from tuffaceous bedrock with a minor influence of volcanic ash in surface horizons. Slopes are 0 to 90 percent. Mean annual precipitation is about 22 inches and mean annual air temperature about 41 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Vitrandic Argixerolls
TYPICAL PEDON: Bolletto ashy loam - forested, on an 18 percent north-facing slope at an elevation of 4,320 feet. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inches; slightly decomposed grasses, needles, cones, twigs
A--1 to 6 inches; dark brown (7.5YR 3/3) ashy loam, brown (7.5YR 5/3) dry; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine roots throughout; common very fine irregular pores; 10 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (3 to 10 inches thick)
AB--6 to 10 inches; dark brown (7.5YR 3/3) ashy loam, brown (7.5YR 5/3) dry; weak fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine, and few fine and medium roots throughout; common very fine irregular pores; 7 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (4 to 12 inches thick)
Bt1--10 to 21 inches; reddish brown (5YR 4/3) gravelly clay, brown (7.5YR 4/4) dry; strong medium subangular blocky structure; very hard, very firm, very sticky and very plastic; many moderately thick clay films on ped faces; few very fine and fine roots throughout; few very fine tubular and few very fine irregular pores; 17 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (5 to 16 inches thick)
Bt2--21 to 25 inches; reddish brown (5YR 4/3) gravelly clay, brown (7.5YR 5/4) dry; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; common moderately thick clay films on ped faces; few fine and very fine roots throughout; few very fine irregular pores; 20 percent gravel; slightly acid (pH 6.4); abrupt wavy boundary. (0 to 23 inches thick)
2R--25 inches; hard tuff
TYPE LOCATION: Crook County, Oregon,
Section 3 (SW1/4, NE1/4, NW1/4), T. 12 S., R. 17 E.
Latitude: 44 degrees, 38 minutes, 45 seconds N.
Longitude: 120 degrees, 40 minutes, 33 seconds W.
UTM coordinates: Zone 10; 4,936,560 northing; 684,570 easting; NAD27
USGS Quadrangle: Dutchman Creek
RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 41 to 46 degrees F
Mean Summer Soil Temperature: 48 to 55 degrees F
Mean Winter Soil Temperature: 33 to 38 degrees F
Soil Moisture: xeric regime, dry 60 to 75 consecutive days in summer
Particle-size Control Section: upper 20 inches of argillic horizon or to a lithic contact
clay content, average: 42 to 48 percent
rock fragment content, average: 0 to 25 percent
Diagnostic Horizons and Features:
vitrandic subgroup properties: upper boundary at the mineral surface (7 to 16 inches thick)
Al+1/2Fe (ammonium oxalate): 0.3 to 0.9 percent
P retention: 20 to 40 percent
glass content in the 0.02-2.0 mm fraction: 5 to 15 percent
mollic epipedon: 9 to 16 inches thick
argillic horizon: 9 to 29 inches thick
lithic contact, depth below mineral surface: 20 to 40 inches
A horizon:
color, moist: 7.5YR 2.5/1, 2.5/2, 3/2, 3/3
color, dry: 7.5YR 4/2, 4/3, 5/3
texture: ASHY-L, ASHY-SIL
clay content: 15 to 27 percent
rock fragment content: 0 to 15 percent total
gravel: 0 to 15 percent
cobbles: 0 to 5 percent
reaction: slightly acid; pH: 6.1 to 6.5
base saturation (sum of cations): 55 to 70 percent
AB horizon: A2 in some pedons:
color, moist: 7.5YR 2.5/2, 3/2, 3/3
color, dry: 7.5YR 3/2, 4/2, 5/3
texture: ASHY-L, CB-ASHY-L, CB-ASHY-CL, GR-ASHY-L
clay content: 22 to 35 percent
rock fragment content: 5 to 30 percent total
gravel: 5 to 25 percent
cobbles: 0 to 15 percent
stones: 0 to 5 percent
reaction: slightly acid; pH: 6.1 to 6.5
base saturation (sum of cations): 55 to 70 percent
Bt1 horizon:
color, moist: 5YR 4/3; 7.5YR 3/2, 4/2, 4/3, 4/4
color, dry: 7.5YR 4/3, 4/4, 4/6, 5/3
texture: C, GR-CL, SIC, GR-C
clay content: 35 to 50 percent
rock fragment content: 0 to 25 percent total
gravel: 0 to 20 percent
cobbles: 0 to 5 percent
reaction: slightly acid; pH: 6.1 to 6.5
base saturation (sum of cations): 65 to 75 percent
Bt2 horizon; BC horizon in some pedons:
color, moist: 5YR 4/3; 7.5YR 3/4, 4/3, 4/4
color, dry: 7.5YR 4/4, 5/3, 5/4
texture: C, GR-C
clay content: 30 to 45 percent
rock fragment content: 0 to 20 percent total
gravel: 0 to 20 percent
cobbles: 0 to 5 percent
reaction: slightly acid; pH: 6.1 to 6.5
base saturation (sum of cations): 65 to 75 percent
COMPETING SERIES:
Volstead: deep (40 to 60 inches) to lithic contact (basalt); formed in tuffaceous colluvium with mixed volcanic ash mantle
GEOGRAPHIC SETTING:
Landform: convex to planar, mid to upper, erosional mountain backslopes, of water dissected soft pyroclastic flows
Slope gradient: 10 to 45 percent
Parent material: colluvium with an influence of Mazama volcanic ash
Lithology: tuffaceous volcanics from Clarno Formation
Elevation: 3,900 to 5,300 feet
Climate: cold, wet winters; warm, dry summers
Mean annual precipitation: 17 to 26 inches
Mean annual air temperature: 39 to 44 degrees F.
Frost-free period: 35 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Fivebeaver: on plateaus and backslopes; shallow; minor influence of volcanic ash in loamy-skeletal colluvium; under ponderosa pine,
Douglas-fir, common snowberry and mallow ninebark
Grubcreek: on convex to planar, mid to upper, erosional summits and benches; moderately deep without an argillic, under grand fir,
Douglas-fir, ponderosa pine, common snowberry, elk sedge and pinegrass
Hafmau: on rolling mountain sideslopes and benches; shallow to bedrock with an argillic horizon, under
Douglas-fir, ponderosa pine, elk sedge and heartleaf arnica
Humarel: on eroding backslopes of andesitic tuff breccia mudflows; moderately deep to bedrock with an influence of volcanic ash, mollic epipedon and argillic horizon, under ponderosa pine,
Douglas-fir, common snowberry and elk sedge
Lamulita: on eroding backslopes of tuff breccia mudflows; moderately deep to bedrock; an influence of volcanic ash, with mollic epipedon and argillic horizon; under grand fir,
Douglas-fir, common snowberry, birchleaf spiraea and mountain brome
Meaufun: on mountain backslopes with ash mixed with colluvium, a mollic epipedon of and argillic horizon, under
Douglas-fir and ponderosa pine forest
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: slow
USE AND VEGETATION:
Use: timber production, livestock grazing, recreation, wildlife habitat, watershed.
Potential native vegetation: Douglas-fir, ponderosa pine, western juniper, serviceberry, common snowberry, heartleaf arnica, sedum, common yarrow, pine grass, elk sedge, bluebunch wheatgrass and Idaho fescue.
Plant Association: PSME/CAGE (Douglas-fir/elk sedge), PIPO/CAGE (ponderosa pine/elk sedge), PSME/SYAL (Douglas-fir/common snowberry), PIPO/CARU (ponderosa pine/pinegrass), or PIPO/FEID (ponderosa pine/Idaho fescue)
DISTRIBUTION AND EXTENT:
Distribution: MLRA: 10, Central Rocky and Blue Mountains foothills.
Extent: Moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa-Whitman National Forests, 2012.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 1 to 10 inches; A, AB horizons
argillic horizon: 10 to 25 inches; Bt1, Bt2 horizons
vitrandic subgroup properties: 1 to 10 inches; A, AB horizons
particle-size control section: 10 to 25 inches; Bt1, Bt2 horizons
linear extensibility (upper 100 cm) = 4.5 cm horizons
ultic subgroup (base saturation, sum of cations is 65 to 75 percent): 10 to 25 inches; Bt1, Bt2 horizons
National Cooperative Soil Survey
U.S.A.