LOCATION BONITA AZ
Established Series
Rev. AAD
04/2011
BONITA SERIES
The Bonita series consists of very deep, well drained soils that formed in alluvium from basalt and related pyroclastic rock. Bonita soils are on plateaus, fan piedmonts and relict basin floors and have slopes of 0 to 10 percent. The mean annual precipitation is about 14 inches and the mean annual air temperature is about 62 degrees F.
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Haplotorrerts
TYPICAL PEDON: Bonita cobbly silty clay - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 4/3) cobbly silty clay, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to moderate fine granular; slightly hard, friable, moderately sticky and moderately plastic; many fine and medium roots; many fine irregular pores; 20 percent gravel and 10 percent cobble; slightly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary (1 to 3 inches thick).
A2--2 to 8 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; moderate medium and coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many fine and medium roots; few fine irregular pores; 10 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary (3 to 7 inches thick).
Ass--8 to 11 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure; very hard, firm, moderately sticky and very plastic; common fine and medium roots; few stress surfaces and slickensides; few fine gravel; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary (3 to 8 inches thick).
Css--11 to 31 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; massive; very hard, firm, moderately sticky and very plastic; few fine roots; many stress surfaces and intersecting slickensides; few fine gravel; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary (18 to .22 inches thick)
2Btkb1--31 to 40 inches; reddish brown (5YR 5/4) and reddish yellow (7.5YR 7/6) very cobbly clay loam, dark reddish brown (5YR 3/4) and strong brown (7.5YR 5/6) moist; weak and moderate fine and medium subangular and angular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; common fine irregular pores; common distinct clay films on faces of peds; common faint manganese coatings on faces of peds; 20 percent cobble and 20 percent gravel, calcium carbonate coated; many fine, medium and coarse soft accumulations of calcium carbonate; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary (8 to 12 inches thick).
2Btkb2--40 to 53 inches; reddish brown (5YR 4/4) very cobbly clay loam, dark reddish brown (5YR 3/4) moist; weak fine and medium subangular and angular blocky structure; hard, friable, slightly sticky and moderately plastic; few fine roots; common fine irregular pores; common distinct clay films on faces of peds; 20 percent cobble and 20 percent gravel, calcium carbonate coated; common faint manganese coatings on faces of peds; many medium and coarse soft accumulations of calcium carbonate; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary (10 to 15 inches thick).
2Btkb3--53 to 60 inches; reddish brown (5YR 4/4) gravelly clay loam, dark reddish brown (5YR 3/4) moist; massive; hard, friable, slightly sticky and moderately plastic; few fine roots; common fine irregular pores; few faint clay films on faces of peds; common faint manganese coatings on faces of peds; 30 percent gravel and cobble, calcium carbonate coated; many medium and coarse soft accumulations of calcium carbonate; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Graham County, Arizona; 2,280 feet north and 600 feet west of the southeast corner of section 4, T. 11 S., R. 22 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. The epipedon is moist in some part less than 90 days cumulative per year. Ustic aridic soil moisture regime.
Rock Fragments: averages less than 15 percent in the control section
Reaction: neutral to moderately alkaline (pH 6.6. to 8.4)
Cracks: 1 to 5 cm wide to a depth of 20 inches or more
Depth to buried horizon: 25 to 40 inches
Organic Matter: More than 1 percent in the surface
A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3, 4 or 5 dry, 2.5 or 3 moist
Chroma: 2 to 4, dry, 1 to 4 moist
C horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 through 5 dry, 2, 3 or 4 moist
Chroma: 0 through 3, dry or moist
Texture: silty clay, clay, silt loam, silty clay loam, loam
Calcium carbonate equivalent: 0 to 5 percent
2Btkb horizon
Hue: 5YR, 7.5YR
Value: 3 through 7, dry or moist
Chroma: 1 through 6, dry or moist
Texture: Loam, clay loam, sandy clay loam, clay
Calcium carbonate equivalent: 2 to 15 percent
Some pedons contain traces of gypsum throughout.
COMPETING SERIES: This is the
Verhalen (TX) series. Verhalen soils do not have buried paleosols at depths less than 40 inches.
GEOGRAPHIC SETTING: Bonita soils are on floodplains, plateaus, terraces, fan piedmonts and basin floors at elevations of 3,500 to 5,000 feet. These soils formed in alluvium from basalt, cinders and ash, with some influence from andesite and limestone. Slopes range from 0 to 10 percent. The mean annual precipitation is 12 to 16 inches. The mean annual air temperature is 59 to 67 degrees F. The frost-free period is 160 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the McAllister and White House soils. These soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; very slow permeability. Subject to very brief sheet flooding during July-September thunderstorms.
USE AND VEGETATION: Bonita soils are used for livestock grazing and wildlife habitat. The present vegetation is tobosa, sideoats grama, vine mesquite, curly mesquite, Rothrock grama, yucca, cacti and scattered mesquite.
DISTRIBUTION AND EXTENT: Southern Arizona. This series is of moderate extent. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Graham County (Gila River Project), Arizona; 1936.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 8 inches (A1, A2 horizons)
Vertic feature - intersecting slickensides from 11 to 31 inches (Css horizon)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010
Revised for the correlation of Graham County, AZ, Southwestern Part; March, 2011, WWJ
National Cooperative Soil Survey
U.S.A.