LOCATION OASIS UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, mesic Xeric Torrifluvents
TYPICAL PEDON: Oasis fine sandy loam, idle cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak fine granular structure that parts easily to single grained; soft, very friable, nonsticky and nonplastic; few fine roots; few fine and medium vesicular pores; moderately calcareous; moderately alkaline (pH 8.3); abrupt smooth boundary. (4 to 8 inches thick)
AC--5 to 13 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine continuous tubular pores; moderately calcareous; strongly alkaline (pH 9.0); abrupt smooth boundary. (6 to 10 inches thick)
C1--13 to 24 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; few fine continuous tubular pores; strongly calcareous; very strongly alkaline (pH 9.4); gradual wavy boundary. (10 to 15 inches thick)
C2--24 to 36 inches; light yellowish brown (10YR 6/4) very fine sandy loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; few fine continuous tubular pores; strongly calcareous; very strongly alkaline (pH 9.3); clear smooth boundary. (10 to 15 inches thick)
C3--36 to 48 inches; pale brown (10YR 6/3) very fine sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; few fine continuous tubular pores; strongly calcareous; very strongly alkaline (pH 9.1); abrupt smooth boundary. (8 to 14 inches thick)
C4--48 to 60 inches; light brownish gray (10YR 6/2) fine sand, grayish brown (10YR 5/2) moist; single grained; loose; moderately calcareous; very strongly alkaline (pH 9.6)
TYPE LOCATION: Millard County, Utah; NE1/4 section 23, T.15S., R.5W.; lat. 39 degrees 30 minutes 26.16 seconds N. and long. 112 degrees 22 minutes 14.30 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 53 degrees F., and the mean summer soil temperature at a depth of 20 inches is 65 to 72 degrees F. The soil is usually dry in all parts above the base of the moisture control section for more than 50 percent of the time that the soil temperature is above 41 degrees F. The soil moisture regime is Aridic bordering on Xeric.
The exchangeable sodium is in excess of 15 percent and generally in excess of 30 percent and ranges as high as 80 percent. There are gravelly pockets below a depth of 24 inches in some pedons. Organic matter decreases irregularly as depth increases.
The A horizon has value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 or 3. It ranges from moderately to very strongly alkaline.
The C horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3.5 through 5 moist, and chroma of 2 through 4, usually 3 or 4. It is loam, fine sandy loam or sandy loam and has 7 to 18 percent clay, less than 50 percent silt plus clay and less than 20 percent rock fragments. Calcium carbonate equivalent ranges from 3 to 40 percent, but is 5 to 20 percent in most places. There is no calcic horizon within a depth of 40 inches. Textural stratification is common below depth of 24 inches. Reaction is moderately alkaline through very strongly alkaline.
COMPETING SERIES:
Modena (UT) soils have 5YR or 2.5YR hue and are not sodium affected.
Mosida (UT) soils contain less than 15 percent exchangeable sodium.
GEOGRAPHIC SETTING: These soils are on flood plains and alluvial fans and have slopes of 0 to 6 percent, usually 1 to 3 percent. The surface is usually uneven due to soil accumulation around the brush. The soils formed in mixed alluvium from sandstone, shale and some limestone and igneous rocks. These soils occur at elevations of 4,500 to 6,000 feet in a semiarid climate. Mean annual temperature is 48 to 51 degrees F., and the mean summer temperature is about 66 to 73 degrees F. The frost-free period is 105 to 140 days. Average annual precipitation ranges from 7 to 11 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lynndyl and Fruitland soils. Lynndyl soils are not sodium affected and have horizons of strong lime accumulation. Fruitland soils are not sodium affected and have a regular decrease in organic matter content.
DRAINAGE AND PERMEABILITY: Well drained; very slow to medium runoff; moderately slow to moderate permeability.
USE AND VEGETATION: Used for rangeland and irrigated cropland. Principal native vegetation is fourwing saltbush, globemallow, Indian ricegrass and shadscale on areas in good range condition, but in most places the present vegetation is shadscale, squirreltail, yellowbrush, greasewood and annual weeds that are somewhat salt tolerant.
DISTRIBUTION AND EXTENT: Basin and range province in Utah and Nevada. This series is inextensive. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Millard County (Delta Area), Utah, 1919.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 13 inches. (Ap and AC horizons)
Fluvent feature - organic matter content decreases irregularly with depth.
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998".