LOCATION WHY AZEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, hyperthermic Fluventic Haplocambids
TYPICAL PEDON: Why sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; light yellowish brown (10YR 6/4) sandy loam, dark yellowish brown (10YR 4/4) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common fine irregular pores; common fine roots; 2 percent fine gravel; noneffervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 3 inches thick)
Bwl--2 to 9 inches; light yellowish brown (10YR 6/4) sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine irregular pores; common very fine roots; 5 percent gravel; noneffervescent; moderately alkaline (pH 8.0); clear wavy boundary. (4 to l5 inches thick)
Bw2--9 to 15 inches; light brown (7.5YR 6/4) sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; soft, friable, slightly sticky and nonplastic; common fine irregular pores; few fine roots; l0 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 20 inches thick)
Bk1--15 to 25 inches; light brown (7.5YR 6/4) sandy loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common fine irregular pores; few very fine roots; l0 percent fine gravel; common calcium carbonate accumulations in pores and root channels and on undersides of gravel; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (8 to l5 inches thick)
Bk2--25 to 37 inches; light brown (7.5YR 6/4) coarse sandy loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common medium irregular pores; few very fine roots; common calcium carbonate accumulations in root channels and pores and on the undersides of gravel; 2 percent fine gravel; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (6 to l4 inches thick)
Bk3--37 to 60 inches; strong brown (7.5YR 5/6) sandy loam, strong brown (7.5YR 4/6) moist; massive; soft, friable, slightly sticky and slightly plastic; common fine irregular pores; few very fine roots; few thin calcium carbonate accumulations in pores and root channels and patchy on undersides of gravel; 3 percent gravel; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Pinal County, Arizona; l75 east and l00 feet north of the southwest corner of section l5, T. 5 S., R. 2 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, intermittently moist in some part of the soil moisture control section during July-August and December-January. Driest during May and June. Typic aridic soil moisture regime.
Rock fragments - Averages less than 5 percent; some subhorizons have as much as 35 percent. Highly variable from subhorizon to subhorizon in some pedons.
Organic matter - Less than l percent; decreases irregularly with depth.
Calcium carbonate - Slightly or noneffervescent in the upper part; secondary fillings and masses in the lower part. Calcium carbonate equivalent is less than 6 percent.
A horizon
Hue: 7.5YR, 10YR
Value: 5, 6, or 7 dry, 4 or 5 moist
Chroma: 2, 3, 4 or 6 dry, 3, 4 or 6 moist
B horizon
Hue: 7.5YR, 10YR
Value: 5, 6 or 7 dry, 4, 5 or 6 moist
Chroma: 4 or 6, dry and moist
Texture: Coarse sandy loam, sandy loam, fine sandy loam; some pedons have thin strata of finer or coarser textures.
Stratification: Many pedons show weak stratification within and between horizons; slightly to strongly alkaline.
Buried horizons: Buried argillic horizons occur below 40 inches in some pedons.
COMPETING SERIES: These are the Cuerda (AZ) and Valencia (AZ) series. Cuerda soils are dominantly very fine sandy loam and loam in the particle-size control section. Valencia soils have a buried argillic horizon at 20 to 40 inches.
GEOGRAPHIC SETTING: Why soils are on alluvial fans and flood plains. Flooding is occasional, shallow and very brief. In undisturbed areas the proximal end floods more often than the distal end. Elevations range from 300 to 2000 feet. Slopes range from 0 to 3 percent. These soils formed in stratified fan alluvium from mixed sources. The climate is hot, arid continental. The mean annual precipitation is 4 to l0 inches, occurring as summer thunderstorms and gentle winter rain. The mean annual air temperature is 69 to 76 degrees F. The frost-free period is 240 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Cuerda and Valencia soils and the Coolidge, Denure, Gunsight, Pinamt and Rillito soils. Coolidge, Gunsight, Pinamt and Rillito soils have calcic horizons and are on stable slopes above. Denure soils do not have an irregular decrease in organic carbon and are on adjacent terraces.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained, slow runoff; moderately rapid permeability; receives runoff from slopes above.
USE AND VEGETATION: Irrigated areas are used for the production of alfalfa, cotton, citrus, vegetables and small grains. Native areas are used for limited livestock grazing. The vegetation is mesquite, creosotebush, bursage and cacti. Sixweeks grama, filaree and Indianwheat are common after rains.
DISTRIBUTION AND EXTENT: Why soils are moderately extensive in southern Arizona. MLRA is 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pinal County, Western Part, Arizona; l984. Name is from a crossroads town in South Central Arizona.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Cambic horizon - The zone from 2 to 15 inches (Bw1, Bw2 horizons)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.