LOCATION ORO GRANDE NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Lithic Haplustolls
TYPICAL PEDON: Oro Grande stony loam, range. (Colors are for dry soil unless otherwise noted.)
A--0 to 10 inches; grayish brown (10YR 5/2) very stony loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; slightly hard, very friable, slightly sticky and nonplastic; common fine roots; common fine interstitial pores; 15 percent pebbles, 25 percent cobbles, and 10 percent stones; slightly calcareous; moderately alkaline; gradual smooth boundary. (2 to 12 inches thick)
Bk--10 to 16 inches; light brownish gray (10YR 6/2) very cobbly light clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable, sticky and slightly plastic; common fine roots; 15 percent pebbles, 30 percent cobbles, and 15 percent stones; strongly calcareous with carbonates finely divided and dispersed throughout with common, medium, soft masses and thin platy caliche coatings on rock fragments that become nearly continuous in the lower 2 inches; moderately alkaline; abrupt smooth boundary. (2 to 8 inches thick)
R--16 to 20 inches; rhyolite; upper part somewhat weathered and fractured; can be dug into with difficulty.
TYPE LOCATION: Sierra County, New Mexico; 0.35 miles northeast of the junction of New Mexico Highway 52 and on the road leading to Monticello, New Mexico; about 40 feet west of the road and about 150 feet due east of the NW corner of section 31, T.11S., R.7W.
RANGE IN CHARACTERISTICS:
Depth to bedrock:4 to 20 inches
Rock fragments in the particle size control section: 35 to 85 percent
Average annual soil temperature: 47 to 59 degrees F.
Soil moisture: These soils are dry in some part between depths of 4 and 12 inches more than 1/2 the time the soil temperature exceeds 41 degrees F. The driest periods occur between October and June. Aridic ustic moisture regime.
Reaction: neutral to moderately alkaline in the upper part and slightly alkaline to strongly alkaline in the lower part.
A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 moist or dry
Organic matter: 1 to 5 percent.
Bk horizon
Hue: 7.5YR or 10YR
Value: 4 through 6 dry, 2 through 4 moist
Chroma: 2 or 3
Texture: loam or light clay loam
Clay content: averages 18 to 35 percent clay
Calcium carbonate: average carbonate content of the fine earth in the control section ranges from 8 to 14 percent.
COMPETING SERIES: These are the Arbol (NM), Faraway (AZ) and Seralin (NV) series. Arbol soils do not have a Bk horizon and have a paralithic contact above the lithic contact. Faraway soils are neutral to moderately acid. Seralin soils are derived from limestone and are in the Mohave Desert (MLRA 30) and receive most of their precipitation in the winter.
GEOGRAPHIC SETTING: Oro Grande soils are on rocky ridges and sideslopes of the mountainous foothills at elevations of 5,700 to 7,000 feet. Slopes are 3 to 55 percent. The parent materials are fine grained mixed igneous materials consisting mainly of rhyolite and andesite. The climate is semiarid. The mean annual temperature is about 45 to 57 degrees F. The mean annual precipitation is 12 to 16 inches. The frost free season is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deama, Irock and Pena soils. Deama soils have more than 40 percent (weight) of the particles less than 2 mm that are carbonate. Irock and Pena soils are deeper than 20 inches to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Native range and watershed. Native vegetation is blue grama, black grama, hairy grama, sideoats grama, bluestem spp., muhly, galleta, cacti spp., and pinyon juniper trees.
DISTRIBUTION AND EXTENT: Wide distribution along foothills of mountains in southern New Mexico. MLRA 38 & 70C.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Reconnaissance Soil Survey of the lower Rio Grande Watershed, New Mexico, Soil Conservation Survey, 1942.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 0 to 10 inches (A horizon)
Lithic contact - The boundary at 16 inches (R horizon)
Reclassified to an Aridic Lithic subgroup in 2006
Classified according to Keys to Soil Taxonomy Tenth Edition, 2006.