LOCATION SPLANOD AZEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, thermic Lithic Torriorthents
TYPICAL PEDON: Splanod very gravelly fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted).
A--0 to 1 inch; red (2.5YR 5/6) very gravelly fine sandy loam, dark red (5YR 3/6) moist; moderate thick platy parting to moderate fine granular structure; soft, very friable, nonsticky and slightly plastic; few very fine roots; many very fine vesicular pores; 40 percent gravel and 10 percent cobble; strongly effervescent, 30 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary. (1 to 3 inches thick)
Bw--1 to 7 inches; red (5YR 4/6) gravelly sandy clay loam, dark red (5YR 3/6) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common very fine roots; common very fine tubular pores; 15 percent gravel; strongly effervescent, 33 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary. (5 to 7 inches thick)
R--7 inches; sandstone.
TYPE LOCATION: Coconino County, Arizona; on the Hualapai Indian Reservation near the confluence of National Canyon and the Grand Canyon; approximately 3500 feet west and 1000 feet north of the projected southeast corner of Section 14, T. 32 N., R. 6 W.; 36 degrees, 14 minutes, 20 seconds north latitude, 112 degrees, 58 minutes, 52 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during July-September and December-February. Driest period is April through June. Typic aridic soil moisture regime.
Soil temperature: 59 to 62 degrees F.
Depth to bedrock: 6 to 20 inches
Clay content: Averages 18 to 35 percent in the control section; ranges from 12 to 35 percent throughout
Rock fragments: Averages less than 35 percent in the control section
Reaction: slightly alkaline or moderately alkaline
A horizon
Hue: 2.5YR, 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 5 or 6, dry or moist
Bw horizon
Hue: 2.5YR, 5YR
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 4 or 6, dry or moist
Texture: Sandy clay loam, loam, sandy loam
Some pedons contain C horizons rather than Bw horizons and extend to depths of 20 inches
COMPETING SERIES: These are the Delgado (CA), Trigger (CA), and Tidwell (AZ) series. All of these soils have hue yellower than 5YR.
GEOGRAPHIC SETTING: Splanod soils are on mesas and structural benches of the Grand Canyon. These soils formed in colluvium and residuum derived dominantly from sedimentary rocks of the Esplanade formation. Elevations are 4000 to 5000 feet. Slopes range from 2 to 15 percent. The mean annual air temperature is 57 to 60 degrees F. Mean annual precipitation is 8 to 10 inches. The frost-free period is 180 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Rizno soil. Rizno soils occur at higher elevations and have soil temperatures less than 59 degrees F.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately permeability.
USE AND VEGETATION: These soils are used for wildlife habitat and livestock grazing. The present vegetation is mainly black grama, needleandthread, Indian ricegrass, cheatgrass, blackbrush, broom snakeweed, fourwing saltbush, and Utah mortonia.
DISTRIBUTION AND EXTENT: Northern Arizona. These soils are of small extent. MLRA is 30.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Coconino County, Arizona; Soil survey of the Hualapai-Havasupai Indian Reservation, Arizona, Parts of Coconino, Mohave, and Yavapai Counties; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 1 inch (A horizon)
Entisol feature: The absence of diagnostic subsurface horizons
Lithic contact: The boundary at 7 inches (R horizon)