LOCATION ROZA WA+IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xerertic Haplocambids
TYPICAL PEDON: Roza clay loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; strong fine and very fine granular structure; hard, firm, moderately sticky and moderately plastic; common fine roots; common very fine tubular pores; vertical cracks from a polyhedron; slightly alkaline (pH 7.4); abrupt wavy boundary. (2 to 4 inches thick)
BA--2 to 11 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate coarse angular blocky structure; very hard, firm, moderately sticky and moderately plastic; common fine roots; many fine and very fine tubular pores; vertical cracks between peds; slightly alkaline (pH 7.8); abrupt wavy boundary. (0 to 12 inches thick)
Bw1--11 to 19 inches; light brownish gray (10YR 6/2) silty clay, grayish brown (10YR 5/2) moist; strong medium blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine roots; many fine and very fine tubular pores; vertical cracks between peds; slightly alkaline (pH 7.8); abrupt wavy boundary. (6 to 10 inches thick)
Bw2--19 to 26 inches; light brownish gray (10YR 6/2) silty clay, grayish brown (10YR 5/2) moist; weak coarse prismatic structure; hard, firm, moderately sticky and moderately plastic; few fine roots; common fine and very fine tubular pores; slightly alkaline (pH 7.8); clear wavy boundary.
Bw3--26 to 38 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; massive; hard, firm, moderately sticky and moderately plastic; few fine roots; common fine and very fine tubular pores; moderately alkaline (pH 8.0); abrupt wavy boundary. (Combined thickness of the Bw horizon is 14 to 35 inches)
Bk1--38 to 45 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; massive; very hard, firm, moderately sticky and moderately plastic; few fine roots; common fine tubular pores; mycelial lime; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)
Bk2--45 to 60 inches; light gray (2.5Y 7/2) clay loam; grayish brown (2.5Y 5/2) moist; massive; very hard, very firm, moderately sticky and moderately plastic; weakly laminated; mycelial lime and lime coatings on laminations with violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Yakima County, Washington; 300 feet east and 120 feet south of the north quarter corner of section 14, T.14N., R.18E.
RANGE IN CHARACTERISTICS: Depth to calcareous sediments is 18 to 60 inches. The mean annual temperature ranges from 48 to 54 degrees F. These soils are dry between depths of 4 and 12 inches more than 1/2, but less than 3/4 of the time when the soil temperature is above 40 degrees F. The particle size control section has 35 to 60 percent clay and 0 to 5 percent rock fragments. Vertical cracks range in width from 1 to 2 cm and extend from the surface to a depth of about 19 inches. The cracks are closed for more than 60 days in most years. The depth to secondary carbonates ranges from 16 to 40 inches.
The A and BA horizons have hue of 10YR or 2.5Y, value of 5 to 7 dry and 4 or 5 moist and chroma of 2 or 3 moist or dry. It is silty clay, loam, clay or heavy clay loam. This horizon often contains pockets or concentrations of uncoated fine sand.
The Bw horizon has hue of 10YR, 5Y or 2.5Y, value of 5 or 6 dry and 4 or 5 moist, chroma of 2 through 4 dry or moist. It is silty clay, silty clay loam, clay or clay loam. It is slightly alkaline or moderately alkaline.
The Bk horizon has hue of 10YR, 5Y or 2.5Y, value of 6 or 7 dry, 4 or 5 moist, and chroma of 2 through 4 moist or dry. It is a clay, silty clay loam, clay loam or silty clay. It is slightly alkaline or moderately alkaline. The upper part of the C horizon contains pockets of strongly weathered shaley material in some pedons.
COMPETING SERIES: There are no competing series. The Pattani series are similar, but are classified as vertisols.
GEOGRAPHIC SETTING: Roza soils are on uplands, alluvial fans and dissected terraces. Slopes are 0 to 60 percent. These soils formed in fine textured sediments of the Ellensburg formation and mixed alluvium. Elevations are 1,300 to 2,500 feet. In Idaho the elevation ranges 4,500 to 4,600 feet. The climate is semiarid, with hot, dry summers and cool, moist winters. The mean annual precipitation ranges from 8 to 12 inches. The mean January temperature is 28 degrees F.; the mean July temperature is 73 degrees F.; and the mean annual temperature is 48 to 52 degrees F. The frost free season is 130 to 170 days and 110 to 120 days in Idaho.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cowiche, Ritzville, and the Selah series. Cowiche soils on uplands, Ritzville soils on hillslopes and Selah soils on old alluvial fans have less than 35 percent clay in the particle size control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Use is for rangeland, irrigated orchards, and pasture. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, big sagebrush, and winterfat.
DISTRIBUTION AND EXTENT: South central Washington and southern Idaho. Series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yakima County, Washington, 1947.
REMARKS: This series is reclassified based on amendment 17 of Soil Taxonomy.