LOCATION RILLINO AZEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Typic Haplocalcids
TYPICAL PEDON: Rillino gravelly fine sandy loam-rangeland. (Colors are for dry soil unless otherwise noted.) 50 percent surface cover of .25 to 1.0 inch diameter gravel.
A--0 to 1 inch; light brown (7.5YR 6/4) gravelly fine sandy loam, brown (7.5YR 4/4) moist; weak thin and medium platy structure parting to weak fine granular; slightly hard, very friable, nonsticky and nonplastic; many very fine and few fine roots; many fine irregular pores; 30 percent fine gravel; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (1/2 to 2 inches thick)
Bk1--1 to 11 inches; light brown (7.5YR 6/4) gravelly fine sandy loam, brown (7.5YR 4/4) moist; very weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; common fine irregular and few fine tubular pores; 35 percent calcium carbonate coated fine gravel; common fine irregular accumulations of calcium carbonate; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 12 inches thick)
Bk2--11 to 23 inches; light brown (7.5YR 6/4) and pinkish gray (7.5YR 7/2) gravelly loam, brown (7.5YR 5/4) and light brown (7.5YR 6/4) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine tubular pores; 30 percent calcium carbonate coated gravel; many fine irregular and medium rounded soft accumulations of calcium carbonate; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 30 inches thick)
Bk3--23 to 49 inches; pinkish gray (7.5YR 7/2) and light brown (7.5YR 6/4) gravelly loam, light brown (7.5YR 6/4) and brown (7.5YR 5/4) moist; massive; very hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; many very fine and few fine tubular pores; 10 percent fine gravel and 5 percent calcium carbonate nodules; common medium and coarse, soft and hard accumulations of calcium carbonate; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 30 inches thick)
Bk4--49 to 60 inches; light brown (7.5YR 6/4) stratified gravelly sandy loam and very gravelly loamy sand, brown (7.5YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; many irregular pores; 45 percent partially calcium carbonate coated gravel; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Pima County, Arizona; on west side of borrow pit, 3/4 mile south of I-10 and 1/4 mile west of Wilmot Rd; 1,320 feet west and 500 feet south of the northeast corner of sec. 23, T. 17 S., R. 14 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. Typic aridic soil moisture regime.
Rock Fragments: Averages 15 to 35 percent in the control section; can range to 55 percent in any one horizon
Soil Temperature: 61 to 72 degrees F.
Depth to calcic horizon: 5 to 20 inches
Sand size fraction: more than 50 percent fine or coarser in upper part of the control section
A horizon
Hue: 7.5YR, 10YR
Value: 4, 5, 6 or 7 dry, 3, 4 or 5 moist
Chroma: 2, 3 or 4, dry or moist
B horizon
Hue: 7.5YR, 10YR
Value: 5 to 8 dry, 4 to 7 moist
Chroma: 2, 3 or 4, dry or moist
Texture: sandy loam, fine sandy loam, loam in the upper part; can range to include finer or coarser textures in the lower part of the control section
COMPETING SERIES: These are the Algerita (I)(NM), Cronese (CA), Grapevine (NV), Guijarral (CA), Kinley (AZ), Nikey (UT), Wink (TX), Whitlock (AZ), Wink (TX), and Yippin (NM) series. Algerita and Yippin soils are inactive. Cronese, Grapevine, Guijarral, Kinley, and Nikey soils are in the Mohave Desert and are moist in the soil moisture control section for less than 20 days cumulative between July and September. Wink soils are deeper than 20 inches to the calcic horizon. Whitlock soils have less than 15 percent rock fragments.
GEOGRAPHIC SETTING: Rillino soils are on fan terraces at elevations of 1,800 to 4,500 feet. These soils formed in mixed alluvium. Slopes range from 1 to 50 percent. The mean annual precipitation is 7 to 12 inches. The mean annual air temperature is 59 to 70 degrees F. The frost-free period is 190 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Whitlock soils and Anthony, Cave, Continental, Mohave, Stagecoach, Pinaleno, and Tres Hermanos soils. Anthony soils do not have a calcic horizon. Cave soils have an indurated hardpan at depths less than 20 inches. Continental, Mohave, Pinaleno, and Tres Hermanos soils have an argillic horizon. Stagecoach soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained. Medium to high runoff. Moderate permeability.
USE AND VEGETATION: Rillino soils are used for livestock grazing, wildlife habitat, irrigated cropland, and homesite development. The present vegetation is creosotebush, mesquite, whitethorn, ocotillo, burroweed, cacti, fluffgrass, bush muhly, and annuals.
DISTRIBUTION AND EXTENT: Southern and west central Arizona. This series is of moderate extent. Occurs in MLRA 40 and 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Santa Cruz County, Arizona, 1973.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 1 inch (A horizon)
Calcic horizon - the zone from 11 to 49 inches (Bk1 and Bk2 horizons)
There is an error in the type location. The reference to I-10 and Wilmont Rd. does not agree with the PLSS. More importantly, and concerning, is there is no Rillino mapped in either place.
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Updated competing series section December 2008, CEM
Revised for the correlation of AZ661, 2/2009, WWJ
Revised for the correlation of AZ675, 5/2009, WWJ
ADDITIONAL DATA: NSSL data numbers; S79AZ 003 013, S84AZ 003 400, and S84AZ 003 418.