LOCATION LARWOOD UTEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Xeric Calciargids
TYPICAL PEDON: Larwood fine sandy loam- rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 4 inches; pale brown (10YR 6/3) fine sandy loam; dark brown (10YR 4/3) moist; weak coarse subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky, non plastic; few medium and coarse roots and many fine roots; neutral; (pH 7.3); abrupt wavy boundary. (3 to 5 inches thick.)
A2--4 to 12 inches; pale brown (10YR 6/3) loam; yellowish brown (10YR 5/4) moist; weak fine platy structure parting to weak coarse granular; slightly hard, friable, slightly sticky, slightly plastic; many very fine and fine roots; common very fine and fine tubular pores; mildly alkaline (pH 7.4); clear smooth boundary. (5 to 10 inches thick.)
Bw--12 to 19 inches; very pale brown (10YR 7/3) silt loam; yellowish brown (10YR 5/4) moist; moderate coarse angular blocky structure; hard, friable, slightly sticky, slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; slightly effervescent, calcium carbonates are disseminated; 19 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); clear wavy boundary. (7 to 18 inches thick.)
Btk--19 to 39 inches; very pale brown (10YR 7/3) silty clay loam; pale brown (10YR 6/3) moist; weak coarse angular blocky structure parting to moderate fine subangular blocky; very hard, firm, moderately sticky, very plastic; few fine roots; many very fine and fine tubular pores; few thin clay films on faces of peds and in pores; strongly effervescent, calcium carbonate occurs as masses and veins, 36 percent calcium carbonate equivalent; moderately alkaline (pH 8.6); abrupt wavy boundary. (15 to 24 inches thick)
Bk--39 to 45 inches; light brownish gray (10YR 6/2) silt loam; brown (10YR 5/3) moist; massive; hard, friable, slightly sticky, slightly plastic; few laminated lake sediments; strongly effervescent, 27 percent calcium carbonate equivalent; strongly alkaline (pH 9.0); abrupt wavy boundary. (8 to 15 inches thick)
C--45 to 60 inches; light brownish gray (10YR 6/2) very fine sandy loam; brown (10YR 5/3) moist; massive; slightly hard, friable, non sticky and non plastic; very slightly effervescent, 17 percent calcium carbonate equivalent; strongly alkaline (pH 8.8).
TYPE LOCATION: Millard County, Utah; about 5 miles southeast of the town of Lynndyl; 1700 feet west and 1600 feet south of the northeast corner of section 16, T.15 S, R.5W.
RANGE IN CHARACTERISTICS: The average annual soil temperature is 47 to 49 degrees F., and the average summer temperature is 68 to 74 degrees F. It is dry in all parts of the moisture control section for more than one-half of the time the soil temperature is above 41 degrees F. in 6 out of 10 years. The soil moisture regime is aridic bordering on xeric.
The particle size control section averages 27 to 35 percent clay and contains less than 15 percent coarser than very fine sand.
The A horizon has value of 6 dry and 4 or 5 moist and chroma of 2 to 4. It is neutral to slightly alkaline. Texture is fine sandy loam or loam.
The Bw horizon has value of 6 or 7 dry, 5 or 6 moist and chroma of 2 to 4. It is slightly to moderately alkaline. Texture is silty clay loam to clay loam.
The Btk horizon has hue of 10YR, value of 6 or 7 dry, 5 or 6 moist, and chroma of 2 to 4. It is silty clay loam or silt loam. It is moderately to strongly alkaline and moderately to strongly effervescent, with 25 to 40 percent calcium carbonate equivalent.
The Bk horizon has value of 6 or 7 dry, 5 or 6 moist and chroma of 2 to 4. It is moderately to strongly alkaline with 20 to 30 percent calcium carbonate equivalent. Texture is silt loam or silty clay loam.
The C horizon has hue of 10YR, value of 6 or 7 dry, 5 or 6 moist, and chroma of 2 or 3. Texture is silt loam or very fine sandy loam. It is very slightly to strongly effervescent.
COMPETING SERIES:
Power (ID) soils lack Bw horizons and the Bt horizon and Bk horizons are separate.
GEOGRAPHIC SETTING: Larwood soils occur on nearly level lake plains at elevations of 4700 to 4800 feet. Slopes are 0 to 2 percent. The soils formed in lacustrine sediments from mixed sedimentary rocks. The climate is semiarid with 8 to 12 inches of annual precipitation. The frost free period is 120 to 140 days. The mean annual air temperature ranges from 49 to 51 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bandag, Berent, and Taylorsflat soils Bandag, Berent and Taylorsflat soils do not have an argillic horizon and have less than 27 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; slow permeability.
USE AND VEGETATION: Rangeland. Native vegetation is big sagebrush, Indian ricegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Central Utah. MLRA 28A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Millard County, Utah; Millard County, Eastern Part Soil Survey, 1995. The series name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 19 inches. (A1 and A2 horizons.)
Calcic horizon - the zone from 19 to 45 inches. (Btk and Bk horizons.)
Argillic horizon - the zone from 19 to 39 inches (Btk horizon)
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998".