LOCATION VERGAS OREstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Durinodic Xeric Haplargids
TYPICAL PEDON: Vergas loam - on a slope of 1 percent in sagebrush steppe at elevation of 4,475 feet. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; light brownish gray (10YR 6/2) loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure, very friable, slightly sticky and slightly plastic; many very fine roots; many fine vesicular pores; about 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (2 to 4 inches thick)
AB--3 to 5 inches; light brownish gray (10YR 6/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; about 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (0 to 4 inches thick)
BA--5 to 10 inches; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many fine and few medium roots; common very fine tubular pores; about 10 percent gravel; neutral (pH 7.0); gradual wavy boundary. (4 to 8 inches thick)
Bt--10 to 25 inches; pale brown (10YR 6/3) clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few fine roots; few very fine tubular pores; about 10 percent gravel; few faint clay film on peds and in pores; slightly alkaline (pH 7.6); clear wavy boundary. (10 to 20 inches thick)
BC--25 to 29 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine tubular pores; about 20 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 10 inches thick)
2Bq--29 to 60 inches; pale brown (10YR 6/3) extremely gravelly loamy sand, brown (10YR 4/3) moist; massive; hard, firm and brittle, nonsticky and nonplastic; few very fine roots; many very fine irregular pores; about 60 percent gravel; slightly alkaline (pH 7.8).
TYPE LOCATION: Deschutes County, Oregon; about 1100 feet north and 1500 feet east of the southwest corner of section 13, T. 22 S., R. 22 E; 43 degrees, 39 minutes, 27 seconds north latitude and 120 degrees, 01 minutes, 46 seconds east longitude.
RANGE IN CHARACTERISTICS: Soils are moist in winter and spring. They are warmer than 41 degrees F, from April 1 to November 1, and they are dry within this period after July 1. The mean annual soil temperature is 44 to 47 degrees F. Depth to the hard, firm and brittle layer is 14 to 40 inches. Depth to bedrock is more than 60 inches. The upper part of the particle-size control section averages 20 to 35 percent clay and 5 to 35 percent gravel. The lower part averages 0 to 10 percent clay and 35 to 60 percent gravel.
The A horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 2 or 3 moist and dry. It has 0 to 25 percent gravel. It is neutral.
The Bt horizon has value of 5 or 6 dry and 3 or 4 moist, and chroma of 3 or 4 dry and moist. It has 20 to 35 percent clay and 5 to 35 percent gravel. It is loam, clay loam or sandy clay loam. It is neutral or slightly alkaline.
The 2Bq horizon is 25 to 80 percent gravel. This horizon is firm to very firm and brittle, but it lacks a laminar cap and vertical coatings of opal or pendants on rock fragments. It is gravelly, very gravelly or extremely loamy sand or coarse sand. It is slightly or moderately alkaline. Some pedons are calcareous.
The 2C horizon when present has hue of 10YR, value of 6 dry, 3 moist and chroma of 4 moist and dry. It is extremely gravelly coarse sand, very gravelly loamy sand. It has 35 to 70 percent gravel and 2 to 10 percent clay. It is slightly alkaline or moderately alkaline. Some pedons are calcareous.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Vergas soils are on fan terraces, depressions on plateaus and lake terraces at elevations of 4,100 to 6,000 feet. Slopes range from 0 to 8 percent. The soils formed in stratified loamy and sandy sediments and alluvium weathered from lava rocks and ash with minor amounts of eolian material. The climate is characterized by warm dry summers and cold moist winters. The mean annual precipitation is 10 to 12 inches. The mean annual temperature is 43 to 45 degrees F, average January temperature is 27 to 29 degrees F, and average July temperature is 59 to 61 degrees F. The frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brace, Ratto and Swaler soils. Brace soils are fine-loamy and moderately deep to a duripan. Ratto soils are on adjacent lava plains and have a clayey argillic horizon and duripan at shallow depths. Swaler soils are moderately well drained, have abrupt clay increase, and lack a brittle subsoil horizon.
DRAINAGE AND PERMEABILITY: Well drained, slow permeability.
USE AND VEGETATION: Vergas soils are used for livestock grazing and wildlife habitat. Native vegetation mainly is Thurber needlegrass, Idaho fescue, basin wildrye, bluebunch wheatgrass, Sandberg bluegrass, and big sagebrush.
DISTRIBUTION AND EXTENT: Central Oregon east of the Cascade Mountains; MLRA 23. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Deschutes County (Upper Deschutes River Area), Oregon, 1992.
REMARKS: Diagnostic horizons and other features:
Ochric epipedon
Argillic horizon - the zone from 10 to 25 inches (Bt horizon)
Hard, firm, and brittle layer at 29 inches (2Bq horizon)