LOCATION MAJOR AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, carbonatic, thermic Petronodic Calcigypsids
TYPICAL PEDON: Major fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; light brown (7.5YR 6/3) fine sandy loam, brown (7.5YR 5/4) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; few very fine roots; common fine irregular pores; disseminated calcium carbonate and gypsum; 10 percent gravel; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 5 inches thick)
By--2 to 7 inches; brown (7.5YR 5/3) sandy loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; few fine irregular pores; disseminated calcium carbonate and gypsum; violently effervescent, 40 percent calcium carbonate equivalent and 3.8 percent gypsum; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)
Bkyc--7 to 22 inches; light brown (7.5YR 6/3) gravelly loam, light brown (7.5YR 6/4) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine roots; few fine irregular pores; many distinct calcium carbonate coatings on sand and gravel; 20 percent petronodes; disseminated calcium carbonate and gypsum; violently effervescent, 60 percent calcium carbonate equivalent and 2.4 percent gypsum; moderately alkaline (pH 8.2); clear wavy boundary. (7 to 15 inches thick)
Bky--22 to 36 inches; light brown (7.5YR 6/3) loam, light brown (7.5YR 6/4) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine roots; few fine irregular pores; common fine soft irregular masses of calcium carbonate; violently effervescent, 60 percent calcium carbonate equivalent and 3.4 percent gypsum; 5 percent gravel; moderately alkaline (pH 8.2); abrupt wavy boundary. (14 to 20 inches thick)
2Byb--36 to 60 inches; weak red (2.5YR 5/2) clay loam, dusky red (2.5YR 3/2) moist; strong fine angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine roots; common fine tubular pores; few patchy organic coatings on ped faces; very slightly effervescent, 3 percent calcium carbonate equivalent and 10.4 percent gypsum; neutral (pH 7.3).
TYPE LOCATION: Fort Huachuca, Arizona; located at a latitude of 31 degrees, 39 minutes, 50 seconds North and longitude of 110 degrees, 15 minutes, 09 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. Ustic aridic soil moisture regime.
Soil Temperature: 62 to 69 degrees F.
Rock fragments: less than 35 percent gravel and/or petronodes in the control section
Petronodes: 20 to 30 percent. Thought to have formed from calcium and magnesium that precipitated out during fluctuating seasonal water tables under a climate much wetter than the present. Repeated wetting and extreme drying of the soil may have been a factor in nodule development. The petronodes have no internal organization and break down completely in HCL acid but not in water.
Depth to gypsic horizon: 20 to 60 inches
Depth to calcic horizon: 2 to 35 inches
Reaction: neutral to moderately alkaline
A horizon
Hue: 7.5YR, 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Effervescence: strong or violent, 5 to 20 percent calcium carbonate equivalent
Gypsum: 0 to 3 percent
By and Bk horizons
Hue: 7.5YR, 10YR
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 2 through 4, dry or moist
Texture: sandy loam, loam, fine sandy loam
Gypsum: 1 to 4 percent
Effervescence: strong or violent, 20 to 60 percent calcium carbonate equivalent, weighted average is greater than 40
2Byb horizon
Hue: 5YR, 2.5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Texture: clay loam, loam, silty clay
Effervescence: very slight or slight, 2 to 10 percent calcium carbonate equivalent
Gypsum: 5 to 12 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Major soils are on stream terraces and relict basin floors at elevations of 4,000 to 4,400 feet. Slopes range from 0 to 5 percent. These soils formed in alluvium from mixed sources. The mean annual precipitation is 12 to 16 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. The mean annual air temperature is 60 to 67 degrees F. The frost-free period is 180 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Graveyard, Gulch, Reeup, Kaboom, Caralampi and Tombstone soils. Reeup soils are fine textured. Caralampi, Graveyard, and Tombstone soils are loamy-skeletal. Gulch soils do not have gypsic horizons. Kaboom soils are shallow.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes creosotebush, whitethorn, tarbush, desert zinnia, bush muhly and black grama.
DISTRIBUTION AND EXTENT: Southern Arizona. Major soils are of moderate extent. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona; Soil survey of Cochise County, AZ, Douglas-Tombstone Part; 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Calcic horizon - The zone from 2 to 36 inches (By, Bkyc, Bky horizons)
Gypsic horizon - The zone from 36 to 60 inches (2Byb horizon)
Petronodic feature - The presence of 20 percent petronodes from 7 to 22 inches (Bkyc horizon)
Soil Taxonomy Second Edition, 1999