LOCATION PADILLA AZEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ustic Haplargids
TYPICAL PEDON: Padilla sandy clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; reddish brown (5YR 4/4) sandy clay loam, dark reddish brown (5YR 3/4) moist; weak thin platy structure parting to moderate fine granular; slightly hard, friable, sticky and slightly plastic; many fine roots; many very fine vesicular pores; 5 percent fine gravel; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (1 to 3 inches thick)
AB--2 to 8 inches; reddish brown (5YR 4/4) sandy clay loam, dark reddish brown (5YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; many fine roots; common fine tubular pores; few faint clay films lining pores; slightly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 8 inches thick)
Bt--8 to 15 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; strong medium angular blocky structure; hard, firm, very sticky and very plastic; many fine roots; common fine tubular pores; common faint clay films on faces of peds; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (6 to 10 inches thick)
Btk1--15 to 42 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; strong medium prismatic structure parting to strong fine angular blocky; hard, firm, very sticky and very plastic; common fine roots; common fine tubular pores; many faint clay films on faces of peds; strongly effervescent, common fine masses of calcium carbonate, 12 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); clear smooth boundary. (10 to 30 inches thick)
Btk2--42 to 53 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; strong medium prismatic structure parting to strong fine subangular blocky; hard, firm, very sticky and very plastic; common fine roots; common fine tubular pores; many faint clay films on faces of peds; 5 percent fine gravel; violently effervescent, common fine masses of calcium carbonate, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary. (6 to 12 inches thick)
Btk3--53 to 60 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; strong medium prismatic structure parting to strong fine angular blocky; hard, firm, very sticky and very plastic; few fine roots; common fine tubular pores; many faint clay films on faces of peds; 5 percent fine gravel; violently effervescent, many fine irregular and rounded accumulations of calcium carbonate, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).
TYPE LOCATION: Navajo County, Arizona; about 12 miles northeast of Snowflake; 700 feet west and 1,700 feet north of the southeast corner of section 16, T.14. N., R.23 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during July-September and December-March. Driest during May and June. Ustic aridic soil moisture regime.
Rock Fragments: 0 to 10 percent
Soil temperature - 53 to 57 degrees F.
Organic matter content - More than 1 percent in the surface
A horizon
Hue: 2.5YR, 5YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 3 through 6, dry or moist
Reaction: Slightly to moderately alkaline
Bt horizon
Hue: 2.5YR, 5YR
Value: 3 through 6 dry, 3 through 5 moist
Chroma: 3 through 6, dry or moist
Texture: Clay, clay loam, silty clay (35 to 50 percent clay)
Reaction: Slightly to moderately alkaline
Btk horizon
Hue: 2.5YR, 5YR
Value: 3 through 6 dry, 3 through 5 moist
Chroma: 3 through 6, dry or moist
Texture: Clay, clay loam (35 to 55 percent clay)
Calcium carbonate: averages less than 15 percent calcium carbonate equivalent; segregated and disseminated
COMPETING SERIES: These are the Chafin (NM), Hawaikuh (NM), Lonti (AZ), Mags (T) (CO), Servilleta (NM), Silver (NM), and Tobish (UT) soils. Chafin, Mags and Silver soils have hue yellower than 5YR. In addition, Chafin soils do not have visible accumulations of secondary carbonates. Silver series attempts to reflect the effects of soil forming agents unique to the Great Plains. Hawaikah soils have an argillic horizon that does not extend below 40 inches. Servilleta and Tobish soils have bedrock at moderate depths. Lonti soils do not have secondary carbonates in the argillic horizon.
GEOGRAPHIC SETTING: Padilla soils are on fan terraces on undulating plateaus and have slopes of 1 to 10 percent. These soils formed in alluvium from mudstone and sandstone. Elevations range from 4,800 to 6,500 feet. The mean annual precipitation is 10 to 14 inches. The mean annual air temperature is 51 to 55 degrees F. Frost-free period is 130 to 165 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Cerrillos soil. Cerrillos soils are adjacent and average less than 35 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; very slow and slow permeability.
USE AND VEGETATION: Padilla soils are used for livestock grazing and wildlife habitat. Present vegetation is galleta, alkali sacaton, blue grama, sideoats grama, needleandthread, winterfat and fourwing saltbush.
DISTRIBUTION AND EXTENT: Northern Arizona. The series is not extensive. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of Mohave County Area, Arizona, Northeastern Part, and Part of Coconino County; 1992.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the 0 to 8 inches (A, AB horizons)
Argillic horizon - The zone from 8 to 60 inches (Bt, Btk1, Btk2, Btk3 horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Additional Data: NSSL data S86AZ 017 005 and S86AZ 017 006
Update and revision for the competing series section 2/08 DWD