LOCATION DROVAL OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Sodic Aquicambids
TYPICAL PEDON: Droval silt loam on a 2 percent slope, rangeland. (Colors are for dry soil unless otherwise noted.)
Aknz--0 to 4 inches; light brownish gray (10YR 6/2) silt loam, dark brown (10YR 3/3) moist; moderate medium platy structure; soft, very friable, moderately sticky and slightly plastic; many fine and medium roots; many very fine and fine vesicular pores; strongly effervescent-Calcium carbonate is 2 percent, EC is 10 mmhos/cm, SAR is 110; very strongly alkaline (pH 9.6); clear wavy boundary. (2 to 6 inches thick)
Bnz1--4 to 11 inches; grayish brown (10YR 5/2) silty clay, brown (10YR 4/3) moist; weak fine subangular blocky structure parting to moderate medium granular; soft, very friable, very sticky and very plastic; many fine and medium roots; many very fine and fine tubular and irregular pores; EC is 23 mmhos/cm, SAR is 70; moderately alkaline (pH 8.3); clear wavy boundary. (5 to 9 inches thick)
Bnz2--11 to 22 inches; light brownish gray (10YR 6/2) silty clay, brown (10YR 4/3) moist; few medium distinct yellowish brown (10YR 5/6) iron concentrations; moderate medium subangular blocky structure; slightly hard, very friable, very sticky and very plastic; many fine and medium roots; many very fine and fine tubular and irregular pores; EC is 23 mmhos/cm, SAR is 70; moderately alkaline (pH 8.3); clear wavy boundary. (9 to 13 inches thick)
Bnyz--22 to 32 inches; grayish brown (10YR 5/2) clay, dark brown (10YR 3/3) moist; few fine distinct yellowish brown (10YR 5/6) iron concentrations; strong fine angular blocky structure; hard, firm, very sticky and very plastic; common fine and medium roots; many very fine and fine tubular and irregualr pores; EC is 22 mmhos/cm, SAR is 63; common filaments and crystals of gypsum; slightly acid (pH 6.4); clear wavy boundary. (8 to 12 inches thick)
Cnyz1--32 to 46 inches; pale brown (10YR 6/3) silty clay, dark brown (10YR 3/3) moist; common fine prominent brownish yellow (10YR 6/6) iron concentrations; massive; hard, firm, very sticky and very plastic; common fine and medium roots; many fine irregular pores; EC is 22 mmhos/cm, SAR is 57; common filaments and crystals of gypsum; slightly acid (pH 6.1); gradual wavy boundary. (12 to 15 inches thick)
Cnyz2--46 to 61 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; common fine prominent brownish yellow (10YR 6/6) iron concentrations; massive; hard, firm, very sticky and very plastic; few very fine and fine roots; many very fine irregular pores; EC is 22 mmhos/cm, SAR is 57; common filaments and crystals of gypsum; slightly acid (pH 6.1); abrupt smooth boundary. (4 to 20 inches thick)
C--61 inches, fractured lacustrine sediments.
TYPE LOCATION: Harney County, Oregon; about 7 miles northeast of Fields and 300 feet south of power line road in the NW1/4SE1/4, Section 19, T. 37S., R. 34E.
RANGE IN CHARACTERISTICS: The soils are usually dry but in most years are saturated with water within 40 inches of the surface in late winter and spring. The mean annual soil temperature is 49 to 50 degrees F. Depth to fractured lacustrine sediments is 45 to more than 60 inches. Clay content in the textural control section ranges from 40 to 60 percent. Depth to redox concentrations is 10 to 15 inches.
The A horizon has value of 5 or 6 dry and 3 or 4 moist, and chroma of 2 or 3 moist and dry. It has an SAR of 75 to 120 and an EC of 8 to 16 mmhos/cm.
The B horizon has value of 5 or 6 dry and 3 or 4 moist, and chroma of 2 or 3 moist and dry. It is silty clay in the upper part and clay in the lower part. It has an SAR of 45 to 80 and as EC of 16 to 32. It has 0 to 4 percent gypsum.
The C horizon has value of 6 or 7 dry and 5 or 6 moist, and chroma of 2 or 3 moist and dry. It is silty clay of clay with 40 to 55 percent clay. Redox concentrations are present throughout the horizon. It has an SAR of 45 to 80, an EC of 16 to 32 mmhos/cm, and 1 to 4 percent gypsum.
COMPETING SERIES: This is the Alvodest Series. Alvodest soils lack the gypsum in the subsoil and substratum.
GEOGRAPHIC SETTING: Droval soils are on desert valley floors at elevations of 4000 to 4500 feet. Slopes are 0 to 3 percent. The soils formed in lacustrine sediments. The climate is semiarid and summers are dry. The mean annual precipitation is 6 to 12 inches and the mean annual air temperature is 45 to 48 degrees F. The frost-free period is 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Alvodest, and Boravall and Goldrun soils. Goldrun soils are in sandy family and on sand dunes. Boravall soils are poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; slow permeability. Flooding is none. A high water table is present at 6 inches above the surface to 30 inches below the surface from December to April.
USE AND VEGETATION: The soils are used for rangeland. Vegetation commonly is big sagebrush, black greasewood, spiny hopsage, Indian ricegrass, basin wildrye, and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Southeastern Oregon. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon, 1997.
REMARKS: Diagnostic horizons and other features:
Ochric epipedon
Cambic horizon - 4 to 32 inches
Sodic intergrade - SAR over 45 throughout profile
Aquic conditions - soil is saturated for over 90 consecutive days above 1 meter.
ADDITIONAL DATA: Reference sample S820R-025-004