LOCATION ROMERO AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, thermic, shallow Ustic Torriorthents
TYPICAL PEDON: Romero very gravelly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak moderately thick platy structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and few fine and medium roots; many fine interstitial pores; 40 percent fine subrounded gravel; neutral (pH 7.0); abrupt smooth boundary. (1 to 4 inches thick)
A2--2 to 10 inches; very dark grayish brown (10YR 3/2) very gravelly fine sandy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and few fine and medium roots; many fine interstitial pores; 40 percent fine gravel; neutral (pH 7.0); abrupt wavy boundary. (4 to 16 inches thick)
2Crt1--10 to 17 inches; brown (10YR 5/3) and light gray (10YR 7/2) weathered granite (grus), brown (10YR 4/3) and light brownish gray (10YR 6/2) moist; many fine and medium and coarse fractures; many very fine and few fine and medium roots in fractures; very dark grayish brown (10YR 3/2) fine sandy loam, very dark brown (10YR 2/2) moist in fractures; few faint and distinct dark reddish brown (5YR 2/2) clay films on fracture faces; diffuse wavy boundary. (4 to 15 inches thick)
2Crt2--17 to 60 inches; light brownish gray (10YR 6/2) and very pale brown (10YR 7/4) weathered granite (grus); many fine and few medium and coarse roots in fractures; few faint dark reddish brown (5YR 3/4) clay films on fracture faces.
TYPE LOCATION: Pima County, Arizona; in a road cut in a small hill on the south side of the road, about 1495 feet west and 1625 feet south of the northeast corner of section 1, T. 18 S., R. 11 E. Latitude 31 degrees, 53 minutes, 39 seconds N., Longitude 111 degrees, 10 minutes, 12 seconds W.
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 69 degrees F.
Rock fragments - averages 35 to 90 percent
Depth to bedrock - 4 to 20 inches
Reaction - slightly acid to slightly alkaline
Organic matter content - averages 1 to 5 percent
A horizon
Hue: 10YR, 7.5YR
Value: 3 through 6 dry, 2 through 6 moist
Chroma: 1 through 6, dry or moist
Texture: sandy loam, fine sandy loam, loam, loamy sand, coarse sandy loam (averages less than 18 percent clay)
COMPETING SERIES: This is the Schrap (AZ) series. Schrap soils average more than 18 percent clay in the control section.
GEOGRAPHIC SETTING: Romero soils are on pediments, hills and mountains and formed from granite, granodiorite, schist or pegmatitie and gneiss. Elevations range from 3,000 to 5,600 feet. Slopes range from 5 to 70 percent, but are dominantly 10 to 35 percent. The mean annual precipitation ranges from 12 to 16 inches occurring as summer thunderstorms and winter rain. The mean annual air temperature is about 57 to 67 degrees F. The frost-free period is about 180 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lampshire and Oracle series. Lampshire soils have a lithic contact at depths less than 20 inches. Oracle soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderately rapid permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes oak, mesquite, scattered juniper, ocotillo, catclaw, mimosa, calliandra, hackberry, range ratany, shrubby buckwheat, southwest rabbitbrush, pricklypear, cholla, beargrass and bullgrass. Some areas have manzanita, buckthorn and sumac. Grasses are sideoats grama, sand lovegrass, plains lovegrass, purple grama, wolftail, threeawn, black grama, Arizona cottontop, cane beardgrass and bush muhly.
DISTRIBUTION AND EXTENT: Southern Arizona. The Romero series is moderately extensive. MLRA is 38 and 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pima County, Arizona, Eastern Part, 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 10 inches (A1, A2 horizons)
Paralithic contact - the boundary at 10 inches (2Crt1 horizon)
Entisol feature - the absence of diagnostic subsurface horizons
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Revised for the correlation of AZ661, 2/2009, WWJ
Revised for the correlation of AZ675, 5/2009, WWJ