LOCATION ARRIBA NMTentative Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Haplustalfs
TYPICAL PEDON: Arriba gravelly loam--woodland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; 25 percent gravels; neutral (pH 7.2); clear smooth boundary. (1 to 3 inches thick)
Bt1--3 to 10 inches; dark yellowish brown (10YR 4/4) clay, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, firm, sticky and plastic; few fine and medium roots; few thin clay films on faces of peds; neutral (pH 6.8); clear smooth boundary. (5 to 11 inches thick)
Bk1--10 to 14 inches; light yellowish brown (2.5Y 6/4) clay loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, firm, slightly sticky and slightly plastic; few fine roots; violently effervescent with disseminated calcium carbonates; mildly alkaline (pH 7.7); clear gradual boundary. (4 to 10 inches thick)
Bk2--14 to 30 inches; very pale brown (10YR 7/3) clay loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; violently effervescent with disseminated calcium carbonates; moderately alkaline (pH 8.0); clear gradual boundary. (10 to 16 inches thick)
Cr--30 inches; weathered shale.
TYPE LOCATION: Rio Arriba County, New Mexico; 0.25 miles north and 1.3 miles west of junction of NM Highway 115 and U. S. Highway 84; 2,160 feet east and 1,500 feet north of the SW corner of sec. 9, T. 26 N., R. 4 E.
RANGE IN CHARACTERISTICS:
Coarse fragments by volume (surface): 15 to 45 percent gravels
Coarse fragments by volume (profile): 0 to 15 percent gravels
Percent clay in the control section: 35 to 45 percent
Depth to paralithic contact: between 20 to 40 inches
A horizon:
Dry color: 10YR 4/3, 4/4, 5/3
Moist color: 10YR 3/3, 4/4
Texture: gravelly loam, gravelly clay loam, very gravelly loam, or very gravelly clay loam
B horizon:
Dry color: 10YR 4/3, 4/4
Moist color: 10YR 4/3, 4/4
Texture: clay loam or clay
C horizon:
Dry color: 10YR 5/3, 7/3, 8/1; 2.5Y 6/4
Moist color: 10YR 4/3, 5/4, 7/3; 2.5Y 5/4
Texture: clay, clay loam, or silty clay loam
Reaction: mildly to moderately alkaline
Effervescence: strongly to violently effervescence
COMPETING SERIES: These are the Amal, Amos, and Montecito series. The Amal, Amos, and Montecito soils are all deep.
GEOGRAPHIC SETTING: Arriba soils are on hill slopes. Slopes range from 5 to 45 percent. Elevations are 7,400 to 7,700 feet. The soils formed in alluvium from mixed origins. Mean annual precipitation is 15 to 17 inches. Mean annual temperature is 45 to 48 degrees F., and the frost-free season is about 100 to 115 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calendar soils. Calendar soils lack an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Arriba soils are used for fuelwood and wood products. The natural vegetation is pinyon, Rocky Mountain juniper, and pinyon ricegrass.
DISTRIBUTION AND EXTENT: Northern New Mexico. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Rio Arriba County, New Mexico, 1981. Series name is taken from Rio Arriba County. Alternate names are Dumpty and Riba.
REMARKS: DIAGNOSTIC HORIZONS AND FEATURES RECOGNIZED IN THIS PEDON ARE:
Ochric epipedon: The zone from 0 to 3 inches. (A horizon)
Argillic horizon: The zone from 3 to 10 inches. (Bt horizon)
National Cooperative Soil Survey