LOCATION ENCINA OR
Established Series
Rev. WEL/TDT
01/2023
ENCINA SERIES
The Encina series consists of deep, well drained soils that formed in loess and lacustrine sediments on south slopes of dissected terraces. Slopes are 1 to 65 percent. The mean annual precipitation is about 12 inches and the mean annual temperature is about 48 degrees F.
TAXONOMIC CLASS: Fine, smectitic, mesic Calciargidic Argixerolls
TYPICAL PEDON: Encina silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; grayish brown (10YR 5/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine roots; common fine vesicular pores; 20 percent gravel; neutral (pH 6.9); clear smooth boundary. (2 to 6 inches thick)
2A2--4 to 7 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak very fine granular structure; slightly hard, firm, sticky and plastic; common very fine roots; common very fine and fine tubular pores; neutral (pH 7.0); clear smooth boundary. (0 to 6 inches thick)
2Bt--7 to 12 inches; pale brown (10YR 5/3) clay, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine roots; few fine tubular pores; continuous thin clay films on faces of peds; slightly alkaline (pH 7.6);clear smooth boundary. (3 to 12 inches thick)
2Bk1--12 to 18 inches; pale brown (10YR 6/3) silty clay loam, dark yellowish brown (10YR 4/4) moist; massive; hard, friable, sticky and plastic; few very fine roots; few very fine pores; moderately calcareous with splotches of soft powdery lime and mycelia; moderately alkaline (pH 8.1); clear smooth boundary. (3 to 12 inches thick)
2Bk2--18 to 42 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; massive; soft, friable, slightly sticky and slightly plastic; few very fine roots; few very fine pores; strongly calcareous with segregated and disseminated lime; moderately alkaline (pH 8.4); abrupt smooth boundary. (10 to 30 inches thick)
3C--42 to 60 inches; multicolored extremely gravelly loam; massive; hard, firm, slightly sticky and slightly plastic; weakly cemented; about 85 percent gravel.
TYPE LOCATION: Baker County, Oregon; SW1/4NW1/4 sec. 18, T. 10 S., R. 41 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 to 52 degrees F. The soils are dry in all parts between depths of 4 and 12 inches for at least half the time (cumulative) during the period the soil temperature is above 41 degrees F and are dry between depths of 4 and 12 inches for over 80 consecutive days following the summer solstice. The solum is neutral to strongly alkaline, increasing in alkalinity with increasing depth. Depth to lime ranges from 8 to 20 inches. Depth to bedrock is 60 inches or more.
The A horizon has value of 2 through 4 moist and 4 or 5 dry, and chroma of 1 through 3 moist and dry. It has 0 to 30 percent gravel.
The 2Bt horizon has value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist and dry. It is clay or silty clay and averages 40 to 50 percent clay and 0 to 15 percent gravel.
The 2Bk horizon has hue of 10YR or 2.5Y, value of 4 through 7 moist, 6 through 8 dry and chroma of 2 through 4 moist and dry. It is loam, silt loam, silty clay loam, and clay loam and averages 0 to 25 percent coarse fragments of mixed origin including weathered diatomite. Depth to the 3C horizon is deeper than 60 inches in some pedons and the amount of gravel ranges from 35 to 85 percent.
COMPETING SERIES: These are the
Arzo and
Krebs series. Arzo soils are 20 to 40 inches deep to a paralithic contact. Krebs soils have mean annual soil temperature of 53 to 56 degrees F and have sola 20 to 40 inches thick.
GEOGRAPHIC SETTING: Encina soils are on dissected slopes of terrace fronts, usually with southern aspects, at elevations of 2,000 to 4,000 feet. Slopes are 1 to 65 percent. These soils formed in lacustrine materials weathered from argillite, limestone, and diatomite with a thin overlay of volcanic ash and loess. The climate is semiarid, with warm dry summers and cool moist winter. The mean annual precipitation ranges from 9 to 14 inches. The mean annual temperature ranges from 45 to 52 degrees F. The average January temperature about 27 degrees F. The frost-free period is about 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Baker,
Brogan,
Hibbard,
Nagle,
Powder, and
Virtue soils. Baker, Hibbard and Virtue soils have a duripan. Brogan soils are fine-loamy. Nagle soils are on north-facing slopes with frigid soil temperatures and are fine-loamy. Powder soils are deep, silt loam soils on flood plains.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Used for rangeland, small grains, hay pasture, wildlife habitat, and water supply. Native vegetation dominantly is bluebunch wheatgrasss, Sandberg bluegrass, Idaho fescue, rabbitbrush, big sagebrush and wild crab apple.
DISTRIBUTION AND EXTENT: Baker, Malheur and Union Counties in eastern Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County, Oregon, 1978.
National Cooperative Soil Survey
U.S.A.