LOCATION GUAYNAKA AZInactive Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Aridic Lithic Argiustolls
TYPICAL PEDON: Guaynaka very cobbly sandy loam - recreation and wildlife habitat. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; dark reddish gray (5YR 4/2) very cobbly sandy loam, dark reddish brown (5YR 2.5/2) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; few very fine irregular and tubular pores; 25 percent gravel, 20 percent cobble; noneffervescent; neutral (pH 6.6); abrupt smooth boundary.
A2--2 to 7 inches; dark reddish gray (5YR 4/2) very gravelly sandy loam, dark reddish brown (5YR 2.5/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular and few very fine tubular pores; 25 percent gravel, 10 percent cobble; noneffervescent; neutral (pH 7.0); abrupt smooth boundary. (Combined thickness of the A horizons is 3 to 7 inches)
Bt--7 to 11 inches; weak red (2.5YR 4/2) very cobbly sandy clay loam, dark reddish brown (2.5YR 2.5/3) moist; strong fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine, few fine and medium roots; common very fine, few fine irregular and few very fine and fine tubular pores; common faint, few distinct clay films on faces of peds and in pores; 20 percent gravel, 20 percent cobble; noneffervescent; neutral (pH 7.2); abrupt wavy boundary. (3 to 7 inches thick)
R--11 inches; hard dacitic breccia with few very fine fractures between the lithic clasts and tuffaceous matrix, fractures are fine enough to generally exclude roots.
TYPE LOCATION: Coronado National Memorial; located at a latitude of 31 degrees, 20 minutes, 15 seconds North and longitude of 110 degrees, 16 minutes, 8 seconds West.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during July - September and December - February. Driest during May and June. Aridic ustic soil moisture regime.
Soil Temperature: 59 to 64 degrees F.
Rock fragments: averages 35 to 50 percent but can have less than 35 percent in any one horizon
Clay content: averages 18 to 27 percent
Organic matter: 1 to 5 percent
Depth to unweathered bedrock: 6 to 14 inches
Some pedons have 1 to 3 inches of paralithic materials over unweathered bedrock
A horizon
Hue: 5YR, 7.5YR
Value: 4 or 5 dry, 2.5 or 3 moist
Chroma: 2 or 3, dry or moist
Bt horizon
Hue: 2.5YR, 5YR
Value: 4 or 5 dry, 2.5 or 3 moist
Chroma: 2 or 3, dry or moist
COMPETING SERIES: These are the Atascosa (AZ), Costavar (AZ), Silktassel (NM) and Woodcutter (AZ) series. Atascosa soils have hue yellower than 7.5YR and formed on rhyolitic conglomerate and rhyolitic tuff. Costavar soils are moderately alkaline and have a calcium carbonate equivalent of 2 to 10 percent. Silktassel soils formed in colluvium derived from tuff and have more than 60 percent coarse fragments. Woodcutter soils have hue yellower than 5YR and formed on granite, granodiorite, and gneiss.
GEOGRAPHIC SETTING: Guaynaka soils are on hill and mountain side slopes at elevations of 5350 to 6900 feet. Slopes range from 30 to 75 percent. These soils formed in colluvium and residuum from dacitic breccia. The mean annual precipitation is 18 to 23 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. The mean annual air temperature is 57 to 62 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the competing Costavar soils.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for recreation and wildlife habitat. Vegetation includes sideoats grama, sotol, bullgrass, plains lovegrass, Arizona white oak, Emory oak, pinyon pine and alligator juniper.
DISTRIBUTION AND EXTENT: Southern Arizona. Guaynaka soils are of limited extent. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona. Soil survey of Coronado National Memorial; 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 0 to 11 inches (A1, A2, Bt horizons)
Argillic horizon - The zone from 7 to 11 inches (Bt horizon)
Lithic contact - The boundary at 11 inches (R horizon)
Reclassified to Aridic Lithic subgroup in 2006.