LOCATION PRILL OR
Established Series
Rev. TMP/RWL
06/2013
PRILL SERIES
The Prill series consists of moderately deep, well drained soils on foothills. They formed in residuum and colluvium derived dominantly from volcanic tuff or sedimentary rock. Slopes are 2 to 55 percent. The mean annual precipitation is about 14 inches and the mean annual temperature is about 49 degrees F.
TAXONOMIC CLASS: Fine, smectitic, mesic Pachic Palexerolls
TYPICAL PEDON: Prill gravelly silty clay loam - on a 20 percent slope at an elevation of 3500 feet, rangeland. (Colors are for moist soil unless otherwise noted.)
A--0 to 6 inches; black (10YR 2/1) gravelly silty clay loam, very dark gray (10YR 3/1) dry; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine, fine and few medium roots; many very fine, fine and few medium tubular pores; 15 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (5 to 15 inches thick)
2Bt1--6 to 14 inches; very dark grayish brown (10YR 3/2) gravelly clay, dark grayish brown (10YR 4/2) dry; moderate coarse prismatic structure parting to strong medium and coarse subangular blocky; very hard, very firm, very sticky and very plastic; common very fine, fine and few medium roots; common very fine, fine and few medium tubular pores; many prominent clay films on faces of peds and lining pores; 20 percent gravel; neutral (pH 7.0); clear smooth boundary.
2Bt2--14 to 20 inches; dark brown (10YR 3/3) gravelly clay, brown (10YR 4/3) dry, strong medium and coarse subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; 25 percent gravel; neutral (pH 6.8); clear smooth boundary.
2Bt3--20 to 28 inches; brown (10YR 4/3) gravelly clay, brown (10YR 5/3) dry; strong medium and coarse subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine and fine tubular pores; many prominent clay films on faces of peds and lining pores; 30 percent gravel; neutral (pH 6.6); gradual wavy boundary. (combined thickness of the 2Bt horizon is 11 to 28 inches)
3Bt4--28 to 35 inches; brown (10YR 4/3) extremely cobbly silty clay, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; few very fine and fine tubular pores; common distinct clay films on faces of peds and lining pores; 70 percent cobbles and 5 percent gravel; slightly acid (pH 6.4) gradual wavy boundary. (4 to 12 inches thick)
3Cr--35 inches; volcanic tuff.
TYPE LOCATION: Wasco County, Oregon, about 2500 feet east and 2000 feet north of the SW corner of section 10, T.7 S., R.13 E. (Latitude 44 degrees, 58 minutes, 36 seconds N, Longitude 121 degrees, 9 minutes, 48 seconds W) Warm Springs Indian Reservation.
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days within the four months that follow the summer solstice. The mean annual soil temperature is 50 to 52 degrees F. Depth to bedrock is 20 to 40 inches. Depth to the 2Bt discontinuity is 5 to 15 inches. The mollic epipedon is 20 to 30 inches thick and includes the upper part of the 2Bt horizon. Hue is 7.5YR or 10YR. The particle-size control section averages 50 to 60 percent clay with 15 to 30 percent gravel and 0 to 5 percent cobbles.
The A horizon has value of 2 or 3 moist, 3 or 4 dry and chroma of 1 or 2 moist and dry. It is a silty clay loam, clay loam, or loam. It is 20 to 40 percent clay and contains 15 to 25 percent gravel and 0 to 5 percent cobbles
The 2Bt horizon has value of 3 or 4 moist, 4 or 5 dry and chroma of 2 or 3 moist, 2 to 4 dry. It contains 15 to 30 percent gravel and 0 to 5 percent cobbles.
The 3Bt horizon has value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is clay or silty clay and contains 40 to 70 percent cobbles and 0 to 15 percent gravel. Soil reaction is slightly acid to neutral.
COMPETING SERIES: These are the
Mitchtown and
Ridley series. Ridley soils are 40 to 60 inches deep to bedrock. Mitchtown soils are moderately deep to a lithic contact and contain secondary carbonates at depths of 20 to 25 inches.
GEOGRAPHIC SETTING: Prill soils are on gently sloping benches and side slopes of foothills. The soil formed in residuum and colluvium derived dominantly from volcanic tuff or sedimentary rock. Slopes are 2 to 55 percent. Elevations are 2400 to 4200 feet. The climate is characterized by cool and wet winters and hot and dry summers. The mean annual precipitation is 12 to 16 inches. The mean annual temperature is 45 to 50 degrees F. The frost-free period is 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Fawnspring,
Kaskela and
Littlefawn soils. Fawnspring soils are on adjacent forested side slopes and are deep to sedimentary rock. Kaskela soils are on gently sloping benches and side slopes of foothills, are very fine, montmorillonitic mineralogy and deep to sedimentary rock. Littlefawn soils are on adjacent forested north-facing side slopes and have a thin mantle of ash on the surface.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. The native vegetation is antelope bitterbrush, bluebunch wheatgrass, Idaho fescue, and Oregon white oak.
DISTRIBUTION AND EXTENT: Mutton Mountains of North-central Oregon; MLRA 10. The soils of this series are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County (Warm Springs Indian Reservation), Oregon, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the surface to depth of 20 inches (A, 2Bt1 and 2Bt2 horizons).
Argillic horizon - The zone from 6 to 35 inches (2Bt1, 2Bt2, 2Bt3 and 3Bt4 horizons).
Pale feature - argillic horizon with a clayey particle-size class and a abrupt upper boundary (2Bt1 horizon) with a 20 percent absolute clay increase.
Particle-size control section - from 6 to 26 inches (2Bt1, 2Bt2 and upper 6 inches of 2Bt3 horizon)
National Cooperative Soil Survey
U.S.A.