LOCATION WELLTON AZEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, hyperthermic Typic Calciargids
TYPICAL PEDON: Wellton loamy sand - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; light brown (7.5YR 6/4) loamy sand, brown (7.5YR 5/4) moist; weak thin platy structure; soft, very friable; few very fine roots; many fine irregular pores; about 10 percent gravel; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 10 inches thick)
Btk1--8 to 17 inches; reddish yellow (7.5YR 6/6) gravelly sandy loam, strong brown (7.5YR 5/6) moist; weak fine subangular blocky structure; slightly hard, very friable; few fine roots; many fine irregular pores; 30 percent gravel; colloidal stains and clay occur as bridges between grains; common fine irregular calcium carbonate masses; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (3 to 12 inches thick)
Btk2--17 to 29 inches; reddish yellow (5YR 6/6) gravelly sandy loam, yellowish red (5YR 5/6) moist; weak medium subangular blocky structure; slightly hard, very friable; few fine roots; many fine irregular pores; 30 percent gravel; colloidal stains and clay occur as bridges between sand grains; common fine irregular calcium carbonate masses; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (8 to 14 inches thick)
Btk3--29 to 51 inches; reddish yellow (5YR 6/6) gravelly sandy loam, yellowish red (5YR 5/6) moist; weak medium subangular blocky structure; slightly hard, very friable; few fine and medium roots; many fine irregular pores; 25 percent gravel; colloidal stains and clay occur as bridges between sand grains; common medium irregular calcium carbonate masses; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 22 inches thick)
C--51 to 60 inches; light brown (7.5YR 6/4) gravelly coarse sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable; many irregular pores; about 15 percent gravel; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Yuma County, Arizona; about 3 miles south and 3.8 miles west of Wellton; 1,500 feet east and 30 feet north of the southwest corner of section 22, T. 19 W., R. 9 S.
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. Typic aridic soil moisture regime.
Soil temperature - 72 to 76 degrees F.
Rock fragments - Averages less than 15 percent; but ranges up to 60
percent in anyone subhorizon. Gravel are dominantly 2 to 20 mm in diameter.
Depth to calcic horizon - 8 to 24 inches
A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 5, 6, or 7 dry, 4 or 5 moist
Chroma: 4 or 5 dry, 3, 4, or 5 moist
Texture: Sand, loamy sand, sandy loam, fine sandy loam
Organic matter: Less than 1 percent
Reaction: slightly or moderately alkaline
B horizon
Hue: 7.5YR, 5YR, 2.5YR
Value: 4, 5, 6, or 7 dry, 4 or 5 moist
Chroma: 4 or 6, dry or moist
Texture: Sandy loam, loam; some pedons have a thin subhorizon of finer or coarser textures
Reaction: slightly or moderately alkaline
SAR: Usually less than 4, but ranges up to 15
C horizons
Hue: 10YR, 7.5YR, 5YR
Value: 5, 6, or 7 dry, 4, 5, or 6 moist
Chroma: 4 or 6, dry or moist
Texture: Loamy very fine sand, coarse sandy loam, sandy loam
Buried soil: Some pedons have a buried soil beginning at depths of 40 to 60 inches
COMPETING SERIES: This is the Growler (AZ) series. Growler soils have high EC's and SAR's.
GEOGRAPHIC SETTING: Wellton soils are on fan terraces or relict basin floors. They have slopes of 0 to 3 percent. They formed in fan or stream alluvium from mixed sources and eolian deposits. Elevations are 150 to 1,300 feet. The climate is hot, arid continental. Mean annual precipitation is 2 to 10 inches, which falls during summer thunderstorms and as gentle winter rains. Mean January temperature is about 52 degrees F., and the average July temperature is about 92 degrees F. Frost-free period is about 260 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Antho, Dateland, Mohall, and Tremant soils. Antho soils are stratified and on flood plains below. Dateland soils are adjacent and lack argillic horizons. Mohall and Tremant soils are slightly higher and finer textured.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: Used mainly for livestock grazing grazing, but citrus, cotton, alfalfa and small grains are grown under irrigation in some areas. The native vegetation is big galleta, creosotebush, white bursage, ocotillo, Wright's cholla and Christmas cholla.
DISTRIBUTION AND EXTENT: Southwestern Arizona. The soils are moderately extensive. MLRA is 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Yuma County (Yuma-Wellton Area), Arizona; 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 8 inches (A horizon)
Argillic horizon - The zone from 8 to 51 inches (Btk1, Btk2, Btk3 horizons)
Calcic horizon - The zone from 8 to 51 inches (Btk1, Btk2, Btk3 horizons)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.