LOCATION COMORO AZ+NMEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, thermic Ustic Torrifluvents
TYPICAL PEDON: Comoro sandy loam - irrigated cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; brown (7.5YR 5/2) sandy loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many fine irregular pores; slightly alkaline (pH 7.5); clear smooth boundary. (5 to 8 inches thick)
C1--8 to 19 inches; brown (7.5YR 5/3) sandy loam, dark brown (7.5YR 3/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine tubular pores; moderately alkaline (pH 8.0); clear wavy boundary. (5 to 12 inches thick)
C2--19 to 46 inches; light brown (7.5YR 6/3) fine sandy loam, brown (7.5YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many fine and very fine tubular pores; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (20 to 40 inches thick)
C3--46 to 60 inches; light brown (7.5YR 6/3) sandy loam, brown (7.5YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine tubular pores; slightly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Cochise County, Arizona; about 2 miles north of Elfrida; 2,500 feet east and 2,000 feet south of the northwest corner of section 9, T.20 S., R.26 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 - 59 to 72 degrees F.
Stratification- Usually thin strata of finer or coarser material
Rock Fragments - averages less than 35 percent in the control section
Organic matter - more than 1 percent in the surface that decreases irregularly with depth. Commonly dark colored to a depth of 36 inches or more.
Reaction - neutral to moderately alkaline; can range to slightly acid in the upper part
A horizon
Hue: 10YR, 7.5YR
Value: 3, 4 or 5 dry, 2 or 3 moist
Chroma: 1, 2 or 3, dry or moist
Calcium carbonate: none to strongly effervescent
C horizon
Hue: 10YR, 7.5YR
Value: 3 through 6 dry, 2, 3 or 4 moist
Chroma: 1 through 4, dry or moist
Texture: Sandy loam, coarse sandy loam, fine sandy loam, loamy sand (less than 18 percent clay)
Calcium carbonate: Slightly to violently effervescent as disseminated or as filaments. Some areas on alluvial fans, in swales, and along narrow drainageways do not effervesce.
COMPETING SERIES: These are the San Jose and Ubik series. San Jose soils have soil temperatures of about 58 to 62 degrees F., hue redder than 7.5YR from the influence of red sandstone and shale, and occur on the Great Plains as part of MLRA 70. Ubik soils are loam, very fine sandy loam and silt loam in the control section.
GEOGRAPHIC SETTING: Comoro soils are on alluvial fans and flood plains. Elevations range from 2,200 to 5,200 feet. Slopes range from 0 to 8 percent. These soils formed in stratified alluvium from predominantly granite and rhyolite sources. The mean annual precipitation is 12 to 16 inches occurring as summer thunderstorms and winter rain. The mean annual air temperature is 57 to 70 degrees F. Frost-free period is 160 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bodecker, Elgin, McAllister, and Stronghold series and the competing Ubik series. Bodecker soils have sandy-skeletal control sections. Elgin, McAllister, and Stronghold soils are on fan terraces.
DRAINAGE AND PERMEABILITY: Well or somewhat excessively well drained; medium runoff; moderately rapid permeability.
USE AND VEGETATION: Used for livestock grazing and irrigated cropland. Vegetation is catclaw, mesquite, yucca, burroweed, three-awn, grama grasses, Arizona cottontop, bush muhly and annual grasses. Irrigated crops are cotton, small grains, sorghum and alfalfa.
DISTRIBUTION AND EXTENT: Southern Arizona. Comoro soils are extensive. This soil occurs in LRR-D, MLRAs 40, 41, 42.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Santa Cruz County, Arizona; 1930.
REMARKS: Formerly part of the Rucker series that included both typic aridic and ustic aridic soil moisture regimes. The type location for Comoro was moved in 1981 to a typic aridic area in Graham County, Arizona. The Comoro concept has a long history of use and familiarity to ranching, research and soil survey. It is extensively referenced in many documents, publications and thesis. This historical use has prompted us to structure the series as close to the original concept as possible and necessitates moving the type location to a ustic aridic (12 - 16 inch pz) soil moisture regime with a change in classification. Rucker soils have a limited extent and will reflect a typic aridic (<12 inch pz) moisture regime.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 8 inches (Ap horizon)
Entisol feature - the absence of diagnostic subsurface horizons
Classified according to Soil Taxonomy Second Edition, 1999.