LOCATION BELLA AZEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Calcic Petrocalcids
TYPICAL PEDON: Bella fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; brown (7.5YR 4/3) fine sandy loam, dark brown (7.5YR 3/3) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine roots; few fine irregular pores; 3 percent gravel; strongly effervescent, 6 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); clear smooth boundary. (1 to 3 inches thick)
Bw--1 to 10 inches; brown (7.5YR 4/3) loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and few medium roots; many fine irregular and tubular pores; 5 percent gravel; violently effervescent, 7 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); abrupt wavy boundary. (5 to 10 inches thick)
Bk--10 to 15 inches; brown (7.5YR 4/4) gravelly fine sandy loam, dark brown (7.5YR 3/4) moist; massive; soft, very friable, nonsticky and nonplastic; common fine and few medium roots; few fine irregular pores; 30 percent hardpan fragments; violently effervescent, 15 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); abrupt wavy boundary. (5 to 10 inches thick)
Bkym--15 to 25 inches; fractured hardpan; indurated with .25 inch thick laminar cap; calcium carbonate and gypsum cemented; common very fine roots in fractures; abrupt wavy boundary. (5 to 15 inches thick)
2Bkyc--25 to 45 inches; light brown (7.5YR 6/4) gravelly loam, brown (7.5YR 5/4) moist; massive; soft, very friable, moderately sticky and moderately plastic; few very fine and fine roots; few fine tubular pores; common fine soft masses of calcium carbonate and gypsum; 20 percent petronodes and hardpan fragments; violently effervescent, 45 percent calcium carbonate equivalent and 5 percent gypsum; moderately alkaline (pH 8.0); abrupt wavy boundary. (6 to 20 inches thick)
2Btky--45 to 60 inches; reddish brown (5YR 4/4) sandy clay loam, reddish brown (5YR 5/4) moist; moderate fine angular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; few fine tubular pores; common distinct clay films on ped faces and in pores; many distinct calcium carbonate coatings on ped faces; common fine soft masses of calcium carbonate and gypsum; 10 percent petronodes; violently effervescent, 15 percent calcium carbonate equivalent and 10 percent gypsum; moderately alkaline (pH 8.0).
TYPE LOCATION: Sierra Vista, Arizona; located at a latitude of 31 degrees, 44 minutes, 12 seconds North and longitude of 110 degrees, 17 minutes, 20 seconds West; about 2,300 feet north and 2,100 feet east of the southwest corner of section 34, T. 19 S., R. 20 E.
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.
Petronodes: 0 to 20 percent. Petronodes are 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.
Rock fragments: 0 to 20 percent gravel, hardpan fragments, and/or petronodes
Reaction: slightly or moderately alkaline
Clay content: less than 18 percent in the control section
Depth to hardpan: 10 to 20 inches, ranges from 5 to 15 inches thick
A horizon
Hue: 7.5YR, 10YR
Value: 3 through 5, dry or moist
Chroma: 3 through 6, dry or moist
Texture: fine sandy loam, sandy loam, loam
Calcium carbonate equivalent: 3 to 10 percent
Bw and Bk horizon
Hue: 7.5YR, 10YR
Value: 3 through 5, dry or moist
Chroma: 3 or 4, dry or moist
Texture: sandy loam, fine sandy loam, loam
Calcium carbonate equivalent: 5 to 20 percent
Bkyc horizon
Hue: 5YR, 7.5YR
Value: 5 through 8, dry or moist
Chroma: 3 through 6, dry or moist
Texture: sandy clay loam, loam (20 to 35 percent clay)
Calcium carbonate equivalent: 15 to 55 percent
Gypsum content: 2 to 10 percent
2Btky horizon
Hue: 5YR, 7.5YR
Value: 5 through 8, dry or moist
Chroma: 1 through 6, dry or moist
Texture: sandy loam, sandy clay loam, loam (20 to 35 percent clay), also can contain more than 35 percent gravel and/or cobble
Calcium carbonate equivalent: 10 to 20 percent
Gypsum content: 5 to 15 percent
COMPETING SERIES: This is the Shumla series. Shumla soils do not contain gypsum. In addition, Shumla soils are on the Edwards Plateau (LRR-I MLRA 81) and are more moist in May and June.
GEOGRAPHIC SETTING: Bella soils are on low fan terraces at elevations of 4,100 to 4,600 feet. Slopes range from 1 to 10 percent. These soils formed in mixed fan alluvium. 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 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Vana and Major soils. Vana soils contain more than 18 percent clay. Major soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderately rapid permeability above the hardpan and moderately slow below.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes whitethorn, mariola, desert zinnia, tarbush, bush muhly, creosotebush, and black grama.
DISTRIBUTION AND EXTENT: Southern Arizona. Bella 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, Arizona, 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)
Petrocalcic horizon - The zone from 15 to 25 inches (Bkym horizon)
Gypsum accumulation - The zone from 25 to 60 inches (Bkyc, Btky horizons)
Classified according to Soil Taxonomy Second Edition, 1999