LOCATION POLLY OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Calciargidic Argixerolls
TYPICAL PEDON: Polly loam, on a 5 percent slope, rangeland. (Colors are for moist soil unless otherwise noted.)
A--0 to 3 inches; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many very fine and fine roots, few medium; many very fine and fine interstitial pores; neutral (pH 6.8); clear smooth boundary. (2 to 5 inches thick)
Bt1--3 to 11 inches; very dark grayish brown (10YR 3/2) clay loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium subangular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; many very fine and fine roots, few medium and coarse; common very fine and fine tubular pores; common discontinuous faint clay films on faces of peds and lining pores; neutral (pH 6.8); clear smooth boundary.
Bt2--11 to 18 inches; dark brown (10YR 3/3) gravelly clay loam, brown (10YR 5/3) dry; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots, few medium and coarse; common very fine and fine tubular pores; few discontinuous faint clay films on faces of peds; 20 percent fine gravel; neutral (pH 7.0); clear smooth boundary. (Combined thickness of the Bt horizon is 10 to 20 inches.)
Bk1--18 to 25 inches; dark brown (10YR 3/3) gravelly loam, pale brown (10YR 6/3) dry; weak medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; 30 percent fine gravel; slightly alkaline (pH 7.4); slightly effervescent; gradual smooth boundary.
Bk2--25 to 31 inches; dark grayish brown (10YR 4/2) loam, pale brown (10YR 6/3) dry; weak fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; 10 percent fine gravel; slightly alkaline (pH 7.6); strongly effervescent with segregated lime in seams; clear smooth boundary.
Bk3--31 to 42 inches; very dark grayish brown (10YR 3/2) loam, brown (10YR 5/3) dry; moderate medium and coarse subangular blocky structure; hard, friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular pores; slightly alkaline (pH 7.8); strongly effervescent with segregated lime in seams; clear wavy boundary.
Bk4--42 to 51 inches; dark grayish brown (10YR 4/2) loam, light brownish gray (10YR 6/2) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; few very fine and fine irregular pores; slightly alkaline (pH 7.8); strongly effervescent with disseminated lime; clear wavy boundary.
Bk5--51 to 60 inches; dark brown (10YR 3/3) loam, brown (10YR 5/3) dry; massive; hard, firm, nonsticky and nonplastic; few very fine, fine and medium roots; few very fine and fine tubular pores; slightly alkaline (pH 7.8); strongly effervescent with segregated lime and seams.
TYPE LOCATION: Crook County, Oregon;. 2500 feet south and 1900 feet east of the NW corner of section 5, T. 17 S, R. 20 E.
RANGE IN CHARACTERISTICS: These soils are usually dry, they are dry in the moisture control section for more than half the time (cumulative) when the soil temperature is above 41 degrees F. The mean annual soil temperature is 50 to 54 degrees F. Depth to bedrock is greater than 60 inches. The mollic epipedon is 10 to 20 inches thick. The particle-size control section contains 25 to 35 percent clay. Depth to calcium carbonate accumulation and the base of the argillic horizon is 15 to 25 inches.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It contains 0 to 10 percent gravel.
The Bt horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is clay loam, silty clay loam or sandy clay loam and contains 0 to 25 percent gravel.
The Bk horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is loam or sandy loam and contains 0 to 30 percent gravel. It is slightly to moderately alkaline. It is slightly to violently effervescent.
COMPETING SERIES: These are the Axford, Benwy, Caliralls, Drybed, Haw, and Zen series. Axford soils are deep to a paralithic contact. Zen soils are moderately deep to a lithic contact. Benwy soils have 18 to 28 percent clay in the control section and are 24 to 38 inches to secondary carbonates. Caliralls soils are 25 to 43 inches to secondary carbonates. Drybed soils are 8 to 20 inches deep to secondary carbonates and carbonates are present throughout the argillic horizon. Haw soils have carbonates at 22 to 38 inches and are greater than 5 inches to the top of the argillic horizon.
GEOGRAPHIC SETTING: Polly soils are on fan terraces at elevations of 3,000 to 3,800 feet. Slopes range from 1 to 15 percent. These soils formed in mixed alluvium and colluvium with a minor influence of volcanic ash in the surface. The climate is characterized by cool, wet winters and hot, dry summers. The mean annual precipitation is 9 to 12 inches, the mean annual temperature is 48 to 52 degrees F, and the frost-free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Lickskillet, Redslide, Simas, Tub, Veazie, and Willowdale soils. Lickskillet soils are shallow, loamy-skeletal and are on adjacent south slopes of foothills. Redslide soils are moderately deep, loamy-skeletal and are on adjacent south slopes of foothills. Simas soils are deep, clayey, and are on adjacent south slopes of foothills. Tub soils are very deep, clayey, and are on adjacent north slopes of foothills. Veazie soils are moderately deep to sand and gravel, coarse-loamy, and are on adjacent floodplains. Willowdale soils are deep to very deep to sand and gravel, fine-loamy, and are on adjacent floodplains.
DRAINAGE AND PERMEABILITY: Well drained; permeability is moderately slow.
USE AND VEGETATION: This soil is used mainly for pasture and rangeland. Native vegetation is basin wildrye, Idaho fescue, bluebunch wheatgrass, Indian ricegrass, and basin big sagebrush.
DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Prineville Area Survey, Crook County, Oregon, 1963.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon - the zone from the surface to a depth of 18 inches (A, Bt1 and Bt2 horizons).
Argillic horizon - the zone from 3 to 18 inches ( Bt1 and Bt2 horizons).
Calcic feature - segregated and disseminated lime in the zone from 18 to 60 inches ( Bk1, Bk2, Bk3, Bk4, and Bk5 horizons).