LOCATION CALZACORTA ORTentative Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Xeric Haplocambids
TYPICAL PEDON: Calzacorta stony loam, range. (Colors are for dry soil unless otherwise noted.)
A11--0 to 4 inches; light brownish gray (10YR 6/2) stony loam, brown to dark brown (10YR 4/3) moist; weak coarse platy structure; soft, friable, nonsticky, nonplastic; few medium roots; many very fine round pores; 15 percent stones, 15 percent cobbles and 5 percent pebbles; mildly alkaline (pH 7.8); abrupt smooth boundary. (4 to 7 inches thick)
B21--4 to 9 inches; brown (10YR 5/3) stony clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, firm, sticky, plastic; few medium roots; many very fine irregular pores; 10 percent basalt stones, 10 percent cobbles and 5 percent pebbles; moderately alkaline (pH 8.0); abrupt smooth boundary. (4 to 6 inches thick)
B22--9 to 12 inches; light brown (7.5YR 6/4) stony clay loam, dark reddish brown (5YR 3/4) or dark brown (7.5YR 4/4) crushed moist; weak fine subangular blocky structure; slightly hard, firm, sticky, plastic; few medium fine roots; few very fine irregular pores; 15 percent basalt stones, 10 percent cobbles, and 5 percent pebbles; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 6 inches thick)
IIR--12 inches; basalt bedrock with silica and calcium carbonate coatings on the contact surface.
TYPE LOCATION: Malheur County, Oregon; SE1/4 SW1/4 section 25, T. 34 S., R. 40 E; 40 feet east of U. S. 95 above road cut in solid basalt.
RANGE IN CHARACTERISTICS: In most years, the soils are dry for more than one-half time when soil temperature is greater than 41 degrees F., between 4 inches and the lithic contact and are moist at least 60 days during the winter months. The mean annual soil temperature ranges from 50 to 54 degrees F. Thickness of the solum and depth to bedrock ranges from 11 to 19 inches. Amount of rock fragments in the solum ranges from 10 to 35 percent of 0 to 30 percent, 5 to 20 percent cobbles, and 5 to 20 percent pebbles.
The A horizon has values of 6 dry and 3 or 4 moist with chromas of 2 or 3 moist and dry. It commonly is loam or silt loam but in some pedons it is very fine sandy loam and fine sandy loam.
The B horizon has hues of 5YR to 10YR, values of 5 or 6 dry and 3 or 4 moist with chromas of 3 or 4. It is clay loam, silty clay laom, sandy clay loam, loam and silt loam with 18 to 35 percent clay.
Basalt bedrock may be fractured with free carbonates in cracks and on lower sides of rock fragments.
COMPETING SERIES: These are the Arron, Slayton, Starbuck, and Trevino series. The Arron soils have frigid soil temperatures and have sandy loam profiles. Slayton soils are moderately coarse textured and underlain by tuff or breccia. Starbuck soils dominantly are medium textured with less than 18 percent clay in the control section and formed in mixed loess, colluvium and alluvium over basalt bedrock. Trevino soils have secondary lime at depths below 8 to 13 inches and have less than 18 percent clay in the control section.
GEOGRAPHIC SETTING: Calzacorta soils are on gently undulating to rolling lava plateaus and on steep faulted and dissected terrain at elevations of 2,500 to 4,200 feet. Slope gradients dominantly range from 3 to 20 percent. The soils formed in mixed colluvium and alluvium weathered from basalt with some influence of loess and eolian materials. The climate is semiarid. Mean annual precipitation is 8 to 10 inches. Mean annual temperature is about 48 to 52 degrees F. The mean summer temperature is 66 to 70 degrees F. The mean winter temperature is 30 to 32 degrees F. The frost-free period ranges from 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Unnamed soils to date.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability; slow to medium runoff.
USE AND VEGETATION: These soils are used for range. The vegetation consists of Sandberg bluegrass, cheatgrass, Atriplex spp., low sage and hopsage.
DISTRIBUTION AND EXTENT: Southeastern Oregon. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Malheur County, Oregon, 1972. Source of name is from the Calzacorta community.
REMARKS: These soils would have been classified as Sierozem.
NSTH 17, RECLASSIFICATION ONLY, 3/95
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.