LOCATION ROSAMOND CA+NM
The Rosamond series consists of deep, well drained soils that formed in material weathered mainly from granitic alluvium. Rosamond soils are on the lower margin of the alluvial fans between the sloping fans and the playas and have slopes of 0 to 2 percent. The mean annual precipitation is about 5 inches and the mean annual air temperature is about 63 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, thermic Typic Torrifluvents
TYPICAL PEDON: Rosamond fine sandy loam, desert range. (Colors are for dry soil unless otherwise noted.)
C1--0 to 4 inches; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak medium and thick platy structure; slightly hard, very friable, nonsticky and nonplastic; common fine roots; many very fine and few fine pores; slightly alkaline (pH 7.8); abrupt smooth boundary. (4 to 6 inches thick)
C2--4 to 8 inches; light brownish gray (10YR 6/2) very fine sandy loam, dark brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; many very fine and few fine pores; slightly effervescent, disseminated lime; moderately alkaline (pH 7.9); clear smooth boundary. (4 to 6 inches thick)
2C3--8 to 28 inches; pale brown (10YR 6/3) light silty clay loam, dark brown (10YR 4/3) moist; weak medium angular blocky structure; hard, friable, sticky and plastic; few fine, medium and coarse roots; many very fine and few fine pores; strongly effervescent;, disseminated lime, few soft spherical concretions of lime; moderately alkaline (pH 8.2); clear wavy boundary. (18 to 24 inches thick)
3C4--28 to 34 inches; pale brown (10YR 6/3) light sandy clay loam, dark brown (10YR 4/3) moist; massive; hard, friable, sticky and plastic; few fine and medium roots; many very fine and few fine pores; slightly effervescent; disseminated lime and few fine filaments of lime; moderately alkaline (pH 8.2); clear wavy boundary. (4 to 10 inches thick)
4C5--34 to 60 inches; light brownish gray (10YR 6/2) loam, dark brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, firm, sticky and plastic; few fine roots; many very fine, few fine and few medium pores; violently effervescent with disseminated lime and common irregular soft bodies of lime; moderately alkaline (pH 8.2).
TYPE LOCATION: Los Angeles County, California; Avenue G and 100th Street East; 11 miles northeast of Lancaster; 0.2 miles east and 30 feet north of the SW corner of section 33, T.8 N., R.10 W.
RANGE IN CHARACTERISTICS: The mean soil temperature ranges from about 63 to 67 degrees F. The soils are usually dry more than 3/4 of the time and are not moist for as long as 60 consecutive days. The soil is very low in organic matter. The organic matter decreases irregularly with increasing depth.
Some pedons have weak A1 horizons, other Ap horizons or lack either of these. The color is about the same throughout the soil. Hue is 10YR or 7.5YR, value is 5 or 6 dry, 4 or 5 moist and chroma ranges from 2 through 4. A few strata have colors of higher chroma. The surface layer is sandy loam to silty clay loam. The 10 to 40 inch control section averages loam, clay loam or silty clay loam and contains 18 to 30 percent clay and more than 15 percent sand. The soil is stratified but lacks contrasting textures within the control section.
Some pedons have contrasting textures below the control section. Structure is weak or the horizons are massive. Usually the soil is calcareous and moderately alkaline throughout except that the upper few inches of some undisturbed pedons are mildly alkaline and noncalcareous. All parts below depths of 10 to 20 inches are calcareous. A few small soft to hard concretions or filaments of lime are common, but they are not definitive for the series. Some pedons contain some salt and alkali but the soil is not typically strongly saline alkali.
COMPETING SERIES: These are the
Leeds series in the same family and the
Panoche, San Emigidio and
Steuber series. Leeds soils have hue of 5YR or 2.5YR in the C horizon. Anthony, Gila, Hesperia,
San Emigdio and Steuber soils have less than 18 percent clay. Docas soils have less than 15 percent of material coarser than very fine sand. Panoche soils are not distinctly stratified and have a regular decrease in organic matter.
GEOGRAPHIC SETTING: Rosamond soils are in the lower margins of fans, between the sloping fans and the basins and playas at elevations from 2,200 to 2,900 feet. Slopes are 0 to 2 percent. The soils formed in alluvium derived mostly from granite and similar rocks. The climate is arid. Precipitation is from 3 to 6 inches. Winters have gentle regional rains and a little snow and summers have very infrequent local thunder showers. The mean annual temperature is between 61 and 65 degrees F.; the average January temperature is about 44 to 45 degrees F.; and the average July temperature is about 80 to 82 degrees F. The frost free season is 200 to 260 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Hesperia soils and the
Tray soils. Cajon soils are sandy throughout. Tray soils have B2t horizons and are strongly alkaline.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate to moderately slow permeability.
USE AND VEGETATION: Large areas are used for desert range. Other extensive areas are irrigated and cropped to alfalfa and row crops. Native vegetation is rabbit brush, big sagebrush, a small amount of Atriplex and a little annual and perennial grass and weeds.
DISTRIBUTION AND EXTENT: The high desert area of Los Angeles and adjoining counties in California. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: Lancaster Area, California, 1922.
Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 5/2001. ET
National Cooperative Soil Survey