LOCATION MOKIAK UT+AZ NM WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Very cobbly sandy loam - rangeland (Colors are for air dry soil unless otherwise noted.
Al--0 to 6 inches; brown (10YR 5/3) very cobbly sandy loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; loose, very friable, non-sticky, nonplastic; common fine and medium, and many very fine roots; few fine and common very fine tubular pores; 50 percent cobbles and gravel; mildly alkaline (pH 7.4); clear wavy boundary. (4 to 12 inches thick)
Bl--6 to 11 inches; brown (10YR 5/3) cobbly heavy sandy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure that parts to moderate very fine subangular blocky structure; slightly hard, very friable, slightly sticky, nonplastic; common medium fine and very fine roots; few fine and medium, and common very fine tubular pores; 40 to 50 percent cobbles and gravel; mildly alkaline (pH 7.4); clear wavy boundary. (0 to 8 inches thick)
B21t--11 to 29 inches; yellowish brown (10YR 5/4) very cobbly sandy clay loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure that parts to moderate fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic; few medium, fine and very fine roots; few coarse and medium, and common fine and very fine tubular pores 55 percent cobbles and gravel; mildly alkaline (pH 7.4); gradual wavy boundary. (11 to 20 inches thick)
B22t--29 to 38 inches; light yellowish brown (10YR 6/4) very cobbly sandy clay loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic; few medium, fine and very fine roots; few fine, and common very fine tubular pores; 80 percent cobbles and gravel; mildly alkaline (pH 7.6); abrupt wavy boundary. (O to 16 inches thick)
R--38 inches; fractured gneiss and schist bedrock
TYPE LOCATION: Washington County, Utah; 1 1/2 miles south of the T.V. relay tower in Beaver Dam Mountains; 1,850 feet south and 525 feet west of the northeast corner of sec. 18, R.42S., R.18W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 10 to 19 inches thick. The soil is noncalcareous throughout. The solum is 30 to 40 inches thick over bedrock. Cobbles and gravel in the argillic horizon range from 45 to 85 percent The mean annual soil temperature is 50 to 54 degrees F., and the mean summer soil temperature is 65 to 70 degrees F. The soils are usually dry during the period the soil temperature is above 41 degrees F. They are moist in some part of the moisture control section for 30 to 40 days during the summer months and are dry for 70 to 85 days during the 120 days following the summer solstice.
The B2t horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 3 or 4. It has weak and moderate very fine through coarse subangular blocky structure .
COMPETING SERIES: These are the Irock, Majada, Montoso, Motoqua, Murdo, Nederland, Santa Fe, and Salas series. Irock soils have a paralithic contact at depths of 20 to 40 inches and have a solum 20 to 30 inches thick. Majada soils have a calcic horizon below the argillic horizon. Montoso soils have a solum 9 to 20 inches thick and have cinders ill the control section. Murdo and Nederland soils are deeper than 40 inches to a lithic contact. Santa Fe and Motoqua soils are less than 20 inches deep to a lithic contact. Salas soils have a horizon of carbonate accumulation.
GEOGRAPHIC SETTING: Mokiak soils are on mountain slopes at elevations of 4,300 to 6,700 feet. Slope gradients are 15 to 70 percent. These soils formed in residuum and colluvium weathered from gneiss and schist. Mean annual temperature is 47 to 52 degrees F., mean summer temperature is 70 to 74 degrees F , average annual precipitation is 14 inches, and the frost-free period is 120 to 160 days
PRINCIPAL ASSOCIATED SOILS: These are the Tortugas, Dagflat, and Welring soils and the competing Motoqua soils. Tortugas and Welring soils lack argillic horizons and Welring soils have ochric epipedons. Dagflat soils have sandy clay loam argillic horizons with less than 35 percent rock fragments.
DRAINAGE AND PERMEABILITY: Well-drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used as rangeland. Vegetation is pinyon, juniper, scrub oak, serviceberry, mountain ash, cliffrose, Brigham tea, tall native bluegrass big sagebrush, snowberry, yucca, and goldenrod.
DISTRIBUTION AND EXTENT: Southwestern Utah. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Washington County, Utah, 1972.
OSED scanned by NSSQA. Last revised by state 4/72.