LOCATION LUTH AZEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Cumulic Haplustolls
TYPICAL PEDON: Luth silt loam - forested (Colors for dry conditions unless otherwise noted.)
A1--0 to 4 inches; dark brown (10YR 3/3) silt loam, very dark brown (10YR 2/2) moist; weak medium platy breaking to moderate fine granular structure; soft, friable, slightly sticky and slightly plastic; plentiful fine and very fine roots; common micro and very fine interstitial pores; noneffervescent; neutral (pH 6.6); abrupt smooth boundary. (4 to 10 inches thick.)
A2--4 to 12 inches; brown (7.5YR 4/2) clay loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few micro and very fine interstitial pores; noneffervescent; neutral (pH 6.8); clear smooth boundary. (6 to 12 inches thick.)
AC1--12 to 31 inches; dark brown (7.5YR 3/2) clay loam, dark brown (7.5YR 3/2) moist; massive; very hard, friable, sticky and plastic; few very fine and fine roots; few very fine interstitial pores; noneffervescent; neutral (pH 6.8); gradual smooth boundary. (16 to 24 inches thick.)
AC2--31 to 52 inches; dark brown (7.5YR 3/2) clay loam, dark brown (7.5YR 3/2) moist; massive; very hard, friable, slightly sticky and plastic; very few fine roots; few very fine interstitial pores; noneffervescent; neutral (pH 7.0); clear smooth boundary. (18 to 24 inches thick.)
C--52 to 71 inches plus; brown (7.5YR 4/4) clay, dark brown (7.5YR 3/2) moist; massive; very hard, friable, slightly sticky and plastic; very few fine roots; few micro and very fine interstitial and very few very fine tubular pores; noneffervescent; neutral (pH 7.2).
TYPE LOCATION: NE1/4 of SW1/4, Sec. 29, T16N, R8E, Coconino County, Arizona.
RANGE IN CHARACTERISTICS:
Soil moisture: Typic ustic moisture regime
These soils may have strata of loam, silt loam or sandy loam below the control section.
Typically, these soils are dark-colored to a depth of 40 inches or more.
The soils may be slightly acid in the surface horizons, but are usually neutral or mildly alkaline.
Hues of the A horizons are 10YR and 7.5YR with values of less than 5.5 dry and 3.5 moist and with chromas of 3 or less.
Surface texture is silt loam, loam, clay loam or clay. Hues of the
AC horizons are dominantly 10YR and 7.5YR but range to 5YR.
Texture of the control section is clay loam, or clay with more than 35 percent clay in the control section.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Luth soils occur in drainageways on nearly level to gently sloping flood plains and low terraces in the ponderosa pine zone at elevations of 6400 to 8000 feet. The soils are forming in recent alluvium derived from basalt and limestone with some influence from calcareous sandstone. The average annual temperature is about 44 degrees F. The mean summer soil temperature at 20 inches is less than 60 degrees F. The average frost-free period is about 120 to 130 days. The mean annual precipitation ranges from 18 to 24 inches and occurs principally as winter snows and as heavy thunderstorms in July and August.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Soldier, Hogg, McVickers and Brolliar series in addition to the Clover Springs series. The Soldier, Hogg, McVickers and Brolliar soils all have argillic horizons.
DRAINAGE AND PERMEABILITY: Well-drained. Surface runoff is slow. Permeability of the profile is moderately slow to slow.
USE AND VEGETATION: Used as rangeland, wildlife and forest. Vegetation consists of blue grama western wheatgrass, ponderosa pine, snakeweed and rabbitbrush.
DISTRIBUTION AND EXTENT: Central Arizona in high elevation grass-pine areas. These soils are limited in extent but are important as range land. MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: St. Johns-Springerville Area, Apache County, Arizona, 1971.
REMARKS: The Luth series was formerly classified in the alluvial soil group.