LOCATION IROCK NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Argiustolls
TYPIFYING PEDON: Irock cobbly sandy loam, range. (Colors are for dry soils unless otherwise noted.)
A1--0 to 7 inches; brown (10YR 4/3) cobbly sandy loam, dark brown (10YR 3/3) moist; weak very fine granular structure; slightly hard, very friable, slightly sticky, nonplastic; many fine and medium roots; common fine, few coarse interstitial pores; 20 percent gravel, 30 percent cobbles with few stones; noncalcareous; neutral; clear wavy boundary. (7 to 12 inches thick)
B2t--7 to 20 inches; yellowish brown (10YR 5/4) and light yellowish brown (10YR 6/4) cobbly heavy sandy loam; dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common fine and medium roots; few fine and medium interstitial pores; few thin clay film coatings on sand grains and pore linings; 25 percent gravel, 40 percent cobble, 5 percent stone; slightly calcareous; mildly alkaline; gradual wavy boundary. (13 to 24 inches thick)
C1ca--20 to 26 inches; yellowish brown (10YR 5/4) cobbly light sandy clay loam, dark yellowish brown (10YR 4/4) moist; structureless; hard, friable, slightly sticky, slightly plastic; few fine and medium roots; few fine and medium interstitial pores; 25 percent gravel, 45 percent cobble, 15 percent stone; thin discontinuous caliche coatings on bottom of coarse fragments; calcareous; mildly alkaline; clear wavy boundary. (5 to 15 inches thick)
IIC2--26 to 42 inches; highly weathered, highly fractured and disintegrated fine grained igneous rock and stone; about 5 percent of the mass in the upper 10 inches is soil material similar to the C1ca horizon; gradual boundary. (10 to 26 inches thick)
R--42 inches; consolidated fine grained igneous bedrock.
TYPE LOCATION: Otero County, New Mexico; about 100 feet west of the Rinconada arroyo on the west side of the road cut in the NE corner of the SW1/4 NE1/4 sec. 14, T.21S., R.11E.
RANGE IN CHARACTERISTICS: The solum is 20 to 30 inches thick. Depth to consolidated bedrock ranges from 42 to 72 inches. The content of coarse fragments in the control section ranges from 35 to 85 percent increasing downward. Average annual soil temperature is 47 degrees to 59 degrees F. These soils are usually dry for more than 90 cumulative days but less than 60 consecutive days in the section from 8 to 25 inches. The driest periods occur between October and June. The solum ranges from neutral to mildly alkaline in the upper part to strongly alkaline in the lower part. The A horizon have hue of 7.5YR or 10YR, value of 3 through 5 dry and 2 or 3 moist and chroma of 2 or 3 dry or moist. It has 1 to 4 percent organic matter. The B2t horizon has hue of 7.5YR or 10YR, value of 4 through 6 dry and 3 or 4 moist with chroma of 3 through 5 dry or moist. It is heavy sandy loam or sandy clay loam containing 18 to 35 percent clay. The C1ca horizon has hue of 5YR through 10YR, value of 4 through 6 dry and 3 through 5 moist and chroma of 3 through 6 dry and moist. Carbonate varies from finely divided and nonvisible forms in the B2t horizon to few medium soft masses and thin discontinuous caliche coatings on the bottom sides of coarse fragments in the C1ca horizon.Carbonate content of the C1ca horizon ranges from 5 to 15 percent.
COMPETING SERIES AND THEIR DIFFERENTIAE: These are the Eicks, Dixmore, Lantis, Majada, Montoso, and Nederland series. Eicks soils have a thermic temperature and are mottled in the argillic horizon. Dixmore soils have less than 18 percent clay in the control section. Lantis soils have sola 7 to 20 inches thick. Majada soils have calcic horizons. Montoso soils have sola 9 to 20 inches thick and have cinders at depths of 12 to 32 inches. Nederland soils are noncalcareous to 40 or more inches and have hues as red or redder than 5YR in the B2t and C horizons.
SETTING: The Irock soils are on moderately sloping to steep dissected old alluvial deposits at elevations of 5,600 to 6,900 feet. The soils formed in materials derived from mixed igneous and sedimentary rocks. Irock soils occur in semiarid climate. Mean annual precipitation is about 14 to 17 inches with a summer maximum. Mean annual temperature is about 45 degrees to 57 degrees F.
PRINCIPAL ASSOCIATED SOILS: These are the Pena, Shanta and Oro Grande soils. Shanta soils are nonskeletal and lack argillic horizons. Oro Grande soils are lithic and lack an argillic horizons. Pena soils have calcic horizons and lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Native range and watershed. Principal native vegetation is blue grama, sideoats grama, hairy grama, cholla and scattered pinyon-juniper trees.
DISTRIBUTION AND EXTENT: Foothills and toe slopes adjoining mountainous areas of south central New Mexico; the series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Otero County (Mescalero-Apache Area), New Mexico, 1970.