LOCATION CASA GRANDE AZ

Established Series
Rev. MHL/FOY/MB/TJC/JEJ/DLR/PDC
12/2011

CASA GRANDE SERIES

The Casa Grande series consists of very deep, well drained soils that formed in old mixed alluvium. Casa Grande soils are on fan terraces and relict basin floors and have slopes of 0 to 5 percent. The mean annual precipitation is about 7 inches (175 mm) and the mean annual air temperature is about 72 degrees F. (22.2 degrees C.)

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, hyperthermic Typic Natrargids

TYPICAL PEDON: Casa Grande fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

An--0 to 1 inch (0 to 2.5 cm); light yellowish brown (10YR 6/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; moderate thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine roots; few very fine irregular pores; strongly effervescent; strongly alkaline (pH 8.6); very slightly saline (ECe 2 dS/m) and slightly sodic (SAR 5); clear smooth boundary.

BAn--1 to 5 inches (2.5 to 12.5 cm); pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; strong medium and coarse angular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine roots; few very fine irregular pores; violently effervescent; strongly alkaline (pH 8.6); very slightly saline (ECe 2 dS/m) and moderately sodic (SAR 28); gradual wavy boundary.

Btknz1--5 to 8 inches (12.5 to 20 cm); light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure; hard, very friable, sticky and plastic; few very fine roots; common very fine tubular and irregular pores; common distinct clay films on ped faces and lining pores; few fine and medium, rounded, soft accumulations of carbonate and salt; violently effervescent (6 percent calcium carbonate equivalent); very strongly alkaline (pH 9.6); slightly saline (ECe 6 dS/m) and strongly sodic (SAR 65); clear smooth boundary.

Btknz2--8 to 11 inches (20 to 27.5 cm); light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure; hard, very friable; sticky and plastic; few very fine roots; common very fine tubular and irregular pores; common distinct clay films on ped faces and lining pores; few fine and medium, rounded, soft accumulations of carbonate and salt; violently effervescent (10 percent calcium carbonate equivalent); very strongly alkaline (pH 9.6); moderately saline (ECe 8 dS/m) and strongly sodic (SAR 107); gradual wavy boundary.

Btknz3--11 to 18 inches (27.5 to 45 cm); strong brown (7.5YR 5/6) clay loam, strong brown (7.5YR 4/6) moist; strong medium prismatic structure parting to strong medium and coarse angular blocky; hard, very friable, sticky and plastic; few very fine and fine roots; common very fine and fine and few fine tubular and irregular pores; many prominent clay films on ped faces and lining pores; many medium and coarse, vertically oriented, cylindrical, soft accumulations of carbonate; violently effervescent (14 percent calcium carbonate equivalent); strongly alkaline (pH 8.8); strongly saline (ECe 16 dS/m) and strongly sodic (SAR 185); gradual wavy boundary.

Btknz4--18 to 32 inches (45 to 80 cm); strong brown (7.5YR 5/6) clay loam, strong brown (7.5YR 4/6) moist; strong medium prismatic structure parting to strong medium and coarse angular blocky; hard, very friable, sticky and plastic; few very fine and fine roots; common very fine and few fine tubular and irregular pores; many prominent clay films on ped faces and lining pores; few dark brown manganese coatings on ped faces; many medium and coarse, vertically oriented, cylindrical, soft accumulations of carbonate; violently effervescent (19 percent calcium carbonate equivalent); strongly alkaline (pH 8.8); strongly saline (ECe 27 dS/m) and strongly sodic (SAR 147); clear wavy boundary.

Btknz5--32 to 39 inches (80 to 97.5 cm); brown (7.5YR 5/4) clay loam, brown (7.5YR 4/4), moist; moderate medium and coarse angular blocky structure; very hard, very friable, sticky and plastic; few very fine irregular pores; few fine clay films bridging mineral grains; few dark brown manganese coatings on ped faces; few fine and medium, rounded, soft accumulations of carbonate; violently effervescent (15 percent calcium carbonate equivalent); strongly alkaline (pH 8.8); strongly saline (ECe 26 dS/m) and strongly sodic (SAR 137); abrupt smooth boundary.

2BCknz1--39 to 46 inches (97.5 to 115 cm); light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few fine irregular pores; 14 percent fine and medium gravel; few dark brown manganese coatings on ped faces; many soft carbonate coatings on gravel; violently effervescent (8 percent calcium carbonate equivalent); strongly alkaline (pH 8.8); strongly saline (ECe 25 dS/m) and strongly sodic (SAR 77); clear smooth boundary.

2BCknz2--46 to 60 inches (115 to 150 cm); light brown (7.5YR 6/4) sandy clay loam, brown (7.5YR 5/4) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; few very fine irregular pores; many coarse and very coarse, soft, rounded accumulations of carbonate; dominantly violently effervescent with spots that are noneffervescent (17 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); strongly saline (ECe 29 dS/m) and strongly sodic (SAR 29).

TYPE LOCATION: Maricopa County, Arizona; on the Gila River Indian Reservation, about 2,650 feet south and 1,800 feet east of the NW corner of sec. 29, T.2 S., R.4 E. Lat. 33 degrees 13 minutes 36 seconds, Long. 111 degrees 58 minutes 21 seconds W., NAD 83

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 78 degrees F. (22.2 to 25.6 degrees C.)

Rock fragments: less than 15 percent; some pedons contain hardpan fragments as a part of the coarse fraction.

Salinity: slightly to strongly saline

Sodicity: slightly to strongly sodic

Depth to calcic horizon: 20 to 40 inches, occurs mostly as vertically oriented, cylindrical masses

Organic matter content: less than one percent

Reaction: moderately alkaline to very strongly alkaline

A horizon
Hue: 10YR, 7.5YR
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 3 to 6, dry or moist

Btn horizon
Hue: 7.5YR, 5YR, 10YR
Value: 3 to 7, dry or moist
Chroma: 3 to 8, dry or moist
Texture: loam, sandy clay loam, clay loam (18 to 35 percent clay)

B, BC or C horizon
Hue: 10YR, 7.5YR, 5YR
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 2 to 8, dry or moist
Texture: sandy clay loam, loam, sandy loam, clay loam, silt loam, silty clay loam; some pedons have strata of coarser textures at 40 to 60 inches. (10 to 25 percent clay)

In some pedons an E horizon occurs below the A horizon and above the Bt horizon. Where present it is from 1 to 3 inches thick.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Casa Grande soils are on nearly level fan terraces and relict basin floors at elevations of 700 to 2,000 feet (213 to 609 m). Slopes range from 0 to 5 percent. These soils formed in old alluvium from a wide variety of rocks including granite, rhyolite, andesite, quartzite and possibly some limestone and basalt. Annual precipitation is 6 to 10 inches (150 to 250 mm); and the mean annual air temperature is 67 to 75 degrees F. (19.4 to 23.9 degrees C.) The frost-free period ranges from 240 to 350 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kamato, Redun, Shontik and Tatai soils. Kamato soils average more than 35 percent clay in the control section. Redun, Shontik and Tatai soils do not have argillic horizons.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; slow or very slow permeability.

USE AND VEGETATION: Used for livestock grazing, wildlife habitat and irrigated cropland. Vegetation is desert saltbush, linear-leaf saltbush, wolfberry and scattered mesquite.

DISTRIBUTION AND EXTENT: Southern Arizona; mainly in the central valley areas. This series is extensive. Total extent is about 260,000 acres. MLRA is 40.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Pinal County (Casa Grande Area), Arizona; 1936.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 1 inch (0 to 2.5 cm) (A horizon)

Natric horizon - the zone from 5 to 39 inches (12.5 to 97.5 cm) (Btknz horizon)

Calcic horizon - the zone from 18 to 39 inches (45 to 97.5 cm) (Btknz4 and Btknz5 horizons)

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006

Revised for the correlation of AZ661, 11/08, PDC

The type location was moved in November 1999 to correspond to the site sampled for the state soil.

The type location was moved sometime between 1957 and 1972 from Pinal County to Maricopa County.

National Cooperative Soil Survey
U.S.A.