LOCATION BABOQUIVARI             AZ

Established Series
Rev. CCC/DJB/PDC/CEM
05/2011

BABOQUIVARI SERIES

The Baboquivari series consist of very deep, well drained soils formed in fan alluvium. Baboquivari soils are on fan terraces and stream terraces with slopes of 1 to 15 percent. The mean annual precipitation is about 14 inches. The mean annual air temperature is about 64 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ustic Haplargids

TYPICAL PEDON: Baboquivari gravelly coarse sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 2 inches; yellowish brown (10YR 5/4) gravelly coarse sandy loam, dark yellowish brown (10YR 3/4) moist; moderate medium platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine, and few medium roots; common fine and medium irregular and tubular pores; 30 percent gravel; noneffervescent; slightly acid (pH 6.3); clear smooth boundary. (0 to 2 inches thick)

A2--2 to 9 inches; brown (10YR 5/3) gravelly coarse sandy loam, dark brown (10YR 3/3) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; common fine and few medium roots; common fine and medium irregular and tubular pores; 30 percent gravel; noneffervescent; slightly acid (pH 6.3); clear wavy boundary. (4 to 10 inches thick)

AB--9 to 14 inches; brown (7.5YR 4/4) gravelly coarse sandy loam, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few medium roots; common fine and medium irregular and tubular pores; 30 percent gravel; noneffervescent; slightly acid (pH 6.3); clear wavy boundary. (0 to 5 inches thick)

Bt1--14 to 40 inches; yellowish red (5YR 5/6) gravelly sandy clay loam, yellowish red (5YR 4/6) moist; moderate coarse prismatic structure parting to weak coarse subangular blocky; very hard, very friable, moderately sticky and moderately plastic; common fine and few medium roots; common fine and medium irregular and tubular pores; common distinct clay films on the faces of peds and coating sand grains; 30 percent gravel; noneffervescent; neutral (pH 7.0); gradual smooth boundary. (20 to 30 inches thick)

Bt2--40 to 51 inches; yellowish red (5YR 5/6) gravelly coarse sandy loam, yellowish red (5YR 4/6) moist; moderate coarse prismatic structure parting to weak coarse subangular blocky; hard, very friable, moderately sticky and moderately plastic; common fine and few medium roots; common fine and medium irregular and tubular pores; common distinct clay films on the faces of peds and coating sand grains; 30 percent gravel; noneffervescent; neutral (pH 7.0); clear wavy boundary. (10 to 30 inches thick)

C--51 to 60 inches; reddish yellow (7.5YR 6/6) gravelly loamy sand, strong brown (7.5YR 5/6) moist; weak coarse prismatic structure parting to weak coarse subangular blocky; hard, very friable, slightly sticky and slightly plastic; common fine and medium irregular and tubular pores; few distinct clay films on faces of peds; 30 percent gravel; noneffervescent; neutral (pH 7.0).

TYPE LOCATION: Pima County, Arizona. Latitude 31 degrees, 56 minutes, 30 seconds North and longitude 111 degrees, 32 minutes, 55 seconds West. 600 feet west and 1200 feet north of the southeast corner of section 17, T. 17 S., R. 8 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) when the soil temperature is above 41 degrees F. in 7 out of 10 years. Ustic aridic soil moisture regime.

Soil temperature: 62 to 69 degrees F.

Rock fragments: 5 to 35 percent gravel in the argillic, and 0 to 35 percent gravel below

Reaction: slightly acid in the upper part and slightly alkaline in the lower part

Organic matter: 1 to 3 percent in the surface

A and AB horizons
Hue: 10YR, 7.5YR
Value: 3 to 5 dry, 2 through 4 moist
Chroma: 0 through 4, dry or moist

Bt horizon
Hue: 5YR, 7.5YR
Value: 3 through 6, dry or moist
Chroma: 2 through 6, dry or moist
Texture: coarse sandy loam, sandy loam, sandy clay loam, loam, clay loam (averages 18 to 30 percent clay)

C horizon
Hue: 5YR, 7.5YR
Value: 3 through 6, dry or moist
Chroma: 3 through 6, dry or moist
Texture: loamy sand, coarse sandy loam, sandy loam

COMPETING SERIES: These are the Canez (TX), Condrone (NM), Courtland (AZ), Triomas (TX) and Walkon (NM) series. Canez and Triomas soils are moist during May and June and occur on the Great Plains. Condrone soils are inactive. Courtland soils contain calcium carbonate at moderate depths and less than 1 percent organic matter. Walkon soils have bedrock at moderate depths.

GEOGRAPHIC SETTING: The Baboquivari soils are on fan terraces and stream terraces. Slope ranges from 1 to 15 percent but are commonly 1 to 8 percent. They formed in fan alluvium derived dominantly from granitic and gneiss materials. Elevation ranges from 2,800 to 5,000 feet. The mean annual precipitation is about 12 to 16 inches. The mean annual air temperature ranges from 60 to 67 degrees F. The frost-free period is about 180 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Combate, Comoro and Oracle soils. Combate and Comoro soils do not have argillic horizons. Oracle soils are shallow to bedrock.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.

USE AND VEGETATION: Baboquivari soils are used for livestock grazing and wildlife habitat. Vegetation is sideoats grama, range ratany, shrubby buckwheat, catclaw acacia, Rothrock grama, cane beardgrass, Arizona cottontop, plains lovegrass, sand dropseed, spike dropseed, greythorn, hairy grama, and black grama.

DISTRIBUTION AND EXTENT: Southern Arizona. This series is of moderate extent. MLRA is 40 and 41.

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

SERIES ESTABLISHED: Pima County, Arizona; Soil survey of Tohono O'odham Indian Reservation, AZ, Parts of Maricopa, Pima and Pinal Counties; 1993.

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

Ochric epipedon - the zone from 0 to 14 inches (A1, A2, AB horizons)

Argillic horizon - the zone from 14 to 51 inches (Bt1, Bt2 horizons)

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

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National Cooperative Soil Survey
U.S.A.