LOCATION RILLOSO NMEstablished Series
TAXONOMIC CLASS: Sandy, mixed, thermic Typic Haplocalcids
TYPICAL PEDON: Rilloso gravelly sandy loam - idle land. (Colors are for dry soil unless otherwise noted.)
Ak--0 to 2 inches; pink (7.5YR 7/3) gravelly sandy loam, brown (7.5YR 5/3) moist; weak fine and medium platy structure; soft, very friable, slightly sticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin, discontinuous calcium carbonate coatings on gravel; moderately alkaline; abrupt smooth boundary. (0 to 4 inches thick)
Bk1--2 to 6 inches; pink (7.5YR 7/3) gravelly sandy loam, brown (7.5YR 5/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin calcium carbonate coatings on gravel; moderately alkaline; clear wavy boundary. (0 to 6 inches thick)
Bk2--6 to 13 inches; pink (7.5YR 7/3) gravelly sandy loam, brown (7.5YR 5/3) moist; weak medium subangular blocky structure; soft to slightly hard, very friable, slightly sticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin calcium carbonate coatings on gravel and few soft calcium carbonate nodules, whiter than the matrix; moderately alkaline; clear wavy boundary. (5 to 10 inches thick)
Bk3--13 to 22 inches; pink (7.5YR 7/3) gravelly sandy loam, brown (7.5YR 5/3) moist; weak medium and coarse subangular blocky structure; hard, very friable, slightly sticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin calcium carbonate coatings on gravel and few soft calcium carbonate nodules, whiter than the matrix; moderately alkaline; clear wavy boundary. (8 to 15 inches thick)
Bk4--22 to 30 inches; pink (7.5YR 7/3) gravelly loamy sand, brown (7.5YR 5/3) moist; weak medium subangular blocky structure; slightly hard to hard, very friable, slightly sticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin carbonate coatings on gravel and few fine calcium carbonate filaments; moderately alkaline; clear wavy boundary. (2 to 10 inches thick)
Bk5--30 to 40 inches; light brown (7.5YR 6/3) gravelly sand, brown (7.5YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; 15 percent gravel; strongly effervescent; thin discontinuous calcium carbonate coatings on gravel and few fine calcium carbonate filaments; moderately alkaline; clear wavy boundary. (0 to 15 inches thick)
C--40 to 50 inches; pinkish gray (7.5YR 7/2) very gravelly sand, brown (7.5YR 5/2) moist; massive and single grain; soft and loose, very friable, nonsticky and nonplastic; few fine roots; 35 percent gravel; parts slightly effervescent and parts noneffervescent; moderately alkaline.
TYPE LOCATION: Dona Ana County, New Mexico; crest of ridge in the SW 1/4, SW 1/4, NW 1/4 of section 11, T.23 S., R.2 E; 106 degrees 42 minutes 58 seconds west longitude and 32 degrees 19 minutes 27 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the soil moisture control section during December through April and for more than 20 days cumulative during July through September. Driest during May and June. Typic aridic soil moisture regime.
Rock fragments: Some thin horizons may be very gravelly, but the particle size control section averages between 0 and 35 percent gravel. These soils are underlain by mostly sandy sediments that may be gravelly, very gravelly or gravel free.
Calcium carbonate: These soils are typically calcareous throughout the particle size control section, but the A horizons of some pedons may be noncalcareous. In some pedons C horizon material that is noncalcareous in part may occur in the lower part of the particle size control section.
A horizon
Hue: 7.5YR, 10YR
Value: 5 through 8 dry, 4 through 7 moist
Chroma: 3 or 4, dry or moist
Texture: sandy loam, loamy sand, sand and their gravelly or very gravelly counterparts
Bk horizon
Hue: 7.5YR, 10YR
Value: 6 through 8 dry, 5 through 7 moist
Chroma: 3 or 4, dry or moist
Texture: sandy loam, loamy sand and their gravelly or very gravelly counterparts
Depth: depth to a calcic horizon ranges from 2 to 16 inches
C horizon
Hue: 7.5YR, 10YR
Value: 6 through 8 dry, 5 through 7 moist
Chroma: 2 or 3, dry or moist
Texture: sand, loamy sand and their gravelly or very gravelly counterparts
COMPETING SERIES: These are the Ambrosia (CA), Arada (NV), Edalph (CA), Knob Hill (NV), and Lovelace (CA) series. These soils are in the Mohave Desert (MLRA 30) receive mostly winter precipitation and are usually dry from April through November.
GEOGRAPHIC SETTING: The Rilloso soils are on alluvial fans and on ridges in dissected terrain. In dissected terrain slopes range from 0 (on ridge crests) to 10 percent on sides of ridges; fans and fan terraces commonly slope from 1 to 3 percent. Elevations range from 4,000 to 5,000 feet. The mean annual precipitation ranges from 7 to 10 inches. The mean annual air temperature ranges from 57 to 63 degrees F. The frost-free period is about 180 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bluepoint, Caliza, Kokan, Nickel, Whitlock, University, and Yturbide soils. Bluepoint, Kokan, University and Yturbide soils do not have calcic horizons. Caliza soils are sandy-skeletal. Nickel soils are loamy-skeletal. Whitlock soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability.
USE AND VEGETATION: Near the type location these soils are mostly idle or used for urban development. Vegetation consists of creosotebush, ratany, fluffgrass and dropseed.
DISTRIBUTION AND EXTENT: Southern New Mexico. The series is of small extent. MLRA is 42.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Dona Ana County, New Mexico (Desert Project); 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (Ak horizon)
Calcic horizon - The zone from 2 to 22 inches (Bk1, Bk2, Bk3 horizons)
Classified according to Soil Taxonomy Second Edition, 1999
This series represents an identified soil within the Desert Soil-Geomorphology Project, Las Cruces, New Mexico. The project was a study of soils and geomorphology in an arid and semi-arid environment. The series is extensively referenced in many documents, publications and thesis. Revision outside the project area is discouraged in order to preserve the historical concept for research.
ADDITIONAL DATA: This is the illustrative pedon at study area 13a in Gile, L.H., J.W. Hawley and R.B. Grossman. 1981. The Desert Project Guidebook. New Mexico Mines & Mineral Resources Memoir 39. Socorro, NM. See S60-NM-13-11 for characterization data.