LOCATION GRANDWASH AZEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, mesic Lithic Haplustalfs
TYPICAL PEDON: Grandwash extremely flaggy sandy loam - grazeable woodland. (Colors are for dry soil unless otherwise noted.)
A--0 to 0.5 inch; reddish brown (5YR 4/4) extremely flaggy sandy loam, dark reddish brown (5YR 3/3) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine irregular pores; 35 percent channers, 40 percent flagstones and 15 percent stones; noneffervescent; neutral (pH 7.0); abrupt smooth boundary. (0.5 to 3 inches thick)
E--0.5 to 2 inches; reddish brown (5YR 5/3) and dark reddish brown (5YR 3/3) channery fine sandy loam, dark reddish brown (5YR 3/3) moist; moderate thick platy structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; many very fine irregular pores and few fine tubular pores; 25 percent channers and 5 percent flagstones; noneffervescent; neutral (pH 7.0); abrupt smooth boundary. (0 to 2 inches thick)
Bt1--2 to 7 inches; reddish brown (5YR 4/4) extremely flaggy clay, dark reddish brown (2.5YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; common fine roots; common fine tubular pores; 30 percent channers, 35 percent flagstones and 5 percent stones; few faint clay films on ped faces and in pores; noneffervescent; neutral (pH 7.2); clear wavy boundary. (2 to 7 inches thick)
Bt2--7 to 12 inches: reddish brown (2.5YR 4/4) and dusky red (2.5YR 3/2) extremely flaggy clay, dark red (2.5YR 3/6) moist; moderate coarse subangular blocky structure; hard, firm, very sticky and very plastic; many fine and few coarse roots; few fine tubular pores; 20 percent channers, 45 percent flagstones, and 10 percent stones; few faint clay films on ped faces and in pores; noneffervescent; neutral (pH 7.2); abrupt wavy boundary. (3 to 7 inches thick)
2R--12 inches; thin bedded, fine grained sandstone.
TYPE LOCATION: Mohave County, Arizona; on the Hualapai Indian Reservation; 2200 feet south and 100 feet west of the northeast corner of section 24, T. 25 N., R. 13 W.
RANGE IN CHARACTERISTICS:
Soil Moisture - Intermittently moist in some part of the soil moisture control section during July through September and December through March. Over half the precipitation falls during the winter months. Driest during May and June. Aridic ustic soil moisture regime.
Rock Fragments - Average rock fragment content in the particle-size control section ranges from 50 to 85 percent. More than half of the fragments are greater than 3 inch diameter, including 10 to 25 percent flagstones greater than 10 inch diameter.
Soil Temperature - 54 to 57 degrees F.
Depth to bedrock - 6 to 20 inches
Organic matter - 1 to 2 percent
A horizon
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Rock fragments: surface layer of 50 to 55 percent flagstones and 30 to 35 percent channers
E horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Bt horizons
Hue: 2.5YR, 5YR
Value: 3, 4, or 5 dry, 3 or 4 moist
Chroma: 4 through 6, dry or moist
COMPETING SERIES: These are the Orejas (NM) and Sombordoro (NM) series. Orejas soils have hues of 7.5YR and 10YR in the argillic horizon and formed in parent material derived from basalt. Sombordoro soils receive 75 percent of their soil moisture during May - September.
GEOGRAPHIC SETTING: Grandwash soils are at elevations of 4700 to 5800 feet on hills. Slopes range from 2 to 25 percent and formed in colluvium and residuum from sandstone and quartzite. The mean annual precipitation is 14 to 16 inches. The mean annual air temperature is 48 to 55 degrees F. The frost-free period is 130 to 165 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deama, Dean, and Pastura soils. Deama soils have carbonatic mineralogy and are derived from limestone. Dean soils are very deep soils with carbonatic mineralogy. Pastura soils are shallow to a petrocalcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Grandwash soils are used for livestock grazing and wildlife habitat. Present vegetation is Utah juniper, singleleaf pinyon, turbinella oak, desert ceanothus, Stansbury cliffrose and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Northwestern Arizona. These soils are of limited extent. MLRA is 39 and 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona, Soil Survey of Hualapai-Havasupai Area, 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 0.5 inch (A horizon)
Argillic horizon - The zone from 2 to 12 inches (Bt1, Bt2 horizons)
Lithic contact - The boundary at 12 inches (2R horizon)
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.