LOCATION GULCH AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ustic Calciargids
TYPICAL PEDON: Gulch gravelly fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; yellowish red (5YR 5/6) gravelly fine sandy loam, dark reddish brown (5YR 3/4) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; few fine irregular pores; 20 percent gravel; slightly effervescent, 5 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary. (1 to 3 inches thick)
Btk1--1 to 3 inches; yellowish red (5YR 4/6) sandy loam, dark reddish brown (5YR 3/3) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; few fine roots; few fine irregular pores; few distinct clay films on ped faces and in pores, and few patchy calcium carbonate coatings on sand and gravel; 10 percent gravel; strongly effervescent, 5 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); abrupt smooth boundary.
Btk2--3 to 10 inches; yellowish red (5YR 4/6) sandy clay loam, dark reddish brown (5YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; few fine tubular pores; common distinct clay films on ped faces and in pores; common patchy calcium carbonate coatings on sand and gravel; common fine calcium carbonate filaments; 10 percent gravel; violently effervescent, 16 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear smooth boundary. (Combined thickness of the Btk horizons is 5 to 15 inches)
Btky1--10 to 24 inches; yellowish red (5YR 5/6) clay loam, reddish brown (5YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; few fine tubular pores; few fine gypsum crystals; common distinct clay films on ped faces and in pores; common fine calcium carbonate filaments; violently effervescent, 17 percent calcium carbonate equivalent and 4 percent gypsum; moderately alkaline(pH 8.2); clear smooth boundary.
Btky2--24 to 30 inches; yellowish red (5YR 5/6) gravelly clay loam, yellowish red (5YR 4/6) moist; strong medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine roots; few fine tubular pores; many distinct clay films on ped faces and in pores; few fine gypsum crystals; common fine soft calcium carbonate masses and filaments; common fine soft masses of iron-manganese; 20 percent gravel; violently effervescent, 8 percent calcium carbonate equivalent and 4 percent gypsum; moderately alkaline (pH 8.2).
Btky3--30 to 40 inches; yellowish red (5YR 5/8) gravelly clay loam, yellowish red (5YR 5/8) moist; strong medium subangular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; few fine tubular pores; many distinct clay films on ped faces and in pores; few fine gypsum crystals; common distinct calcium carbonate coatings on rock fragments and common medium calcium carbonate filaments; few fine soft masses of iron-manganese; 18 percent gravel; strongly effervescent, 13 percent calcium carbonate equivalent and 2 percent gypsum; moderately alkaline (pH 8.0); clear wavy boundary. (Combined thickness of the Btky horizons is 15 to 30 inches)
2Btk--40 to 60 inches; yellowish red (5YR 5/6), and white (5YR 8/1) gravelly clay loam, yellowish red (5YR 4/6), and yellowish red (5YR 5/6) moist; strong medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine tubular pores; many distinct clay films on ped faces and in pores; many distinct calcium carbonate coatings on rock fragments; common distinct organic coatings in root channels and pores; 20 percent gravel; violently effervescent, 51 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).
TYPE LOCATION: Fort Huachuca, Arizona; located at a latitude of 31 degrees, 37 minutes, 05 seconds North and longitude of 110 degrees, 13 minutes, 10 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
Reaction: slightly or strongly alkaline
Clay content: 18 to 35 percent
Organic Matter: less than 1 percent
Gypsum percentage: 1 to 4 percent in the Btky horizons
Depth to calcic horizon: 3 to 20 inches
Calcium carbonate equivalent: ranges from 5 to 55 percent; averages less than 40
A horizon
Hue: 7.5YR, 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 4 to 6, dry or moist
Effervescence: slight or strong
Btk horizon
Hue: 7.5YR, 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 4 to 6 dry, 3 or 4 moist
Texture: sandy clay loam, sandy loam
Effervescence: strong or violent
Btky and 2Btk horizons
Hue: 7.5YR, 5YR
Value: 3 through 8, dry to- moist
Chroma: 1, 6 to 8 dry, 4 through 6 moist
Texture: sandy clay loam, clay loam, sandy loam
Effervescence: strong or violent
COMPETING SERIES: These are the Amorose (NM), Grizzle (AZ), Headquarters (NM), McAllister (AZ), McNeal (AZ), Redona (NM) and Tinney (NM) series. Amorose and Redona soils are moist in the soil moisture control section during May and June and occur in the Great Plains.
Amorose, Redona, Tinney, and McAllister soils have calcic horizons below 20 inches.
Grizzle soils are moderately deep to a paralithic contact.
GEOGRAPHIC SETTING: Gulch soils are on stream terraces, fan terraces, and relict basin floors at elevations of 3,800 to 4,600 feet. Slopes are 0 to 10 percent. These soils formed in calcareous 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 and January. 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, Major, Sasabe, Diaspar, Caralampi and Tombstone soils. Graveyard and Sasabe soils are fine textured. Major soils have a gypsic horizon. Diaspar soils are coarse-loamy. Caralampi and Tombstone soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Used for military training and as an artillery impact area. Vegetation includes creosotebush, javelina bush, whitethorn, desert zinnia, bush muhly, black grama and slim tridens.
DISTRIBUTION AND EXTENT: Southern Arizona. Gulch soils are of moderate extent. MLRA is 41. Name derived from Graveyard Gulch Wash.
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 1 inch (A horizon)
Argillic horizon - The zone from 1 to 60 inches (Btk1, Btk2, Btky1, Btky2, Btky3, 2Btk horizons)
Calcic horizon - The zone from 3 to 60 inches (Btk2, Btky1, Btky2, Btky3, 2Btk horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.