LOCATION FRIJOLES NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal over fragmental, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Frijoles very fine sandy loam--grassland. (Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; brown (10YR 5/3) very fine sandy loam, dark brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine roots; many fine vesicular pores; neutral; abrupt smooth boundary. (2 to 4 inches thick)
Bt1--3 to 8 inches; brown (7.5YR 4/4) very gravelly clay loam, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; many fine roots; many fine vesicular pores; thin discontinuous clay films on faces of peds; 35 percent fine pumice pebbles; neutral; clear smooth boundary. (4 to 8 inches thick)
Bt2--8 to 13 inches; brown (7.5YR 5/4) very gravelly clay loam, dark brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many fine roots; many fine vesicular pores; thin discontinuous clay films on faces of peds; 45 percent fine pumice pebbles; neutral; clear smooth boundary. (4 to 8 inches thick)
2C--13 to 20 inches; pinkish gray (7.5YR 7/2) extremely gravelly sandy loam, pinkish gray (7.5YR 6/2) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine roots; 70 percent pumice pebbles; neutral; clear wavy boundary. (5 to 10 inches thick)
3C--20 to 60 inches; pinkish white (7.5YR 8/2) pumice pebbles, pinkish gray (7.5YR 7/2) moist; few fine roots; strong brown (7.5YR 5/6) lamella; few fine thin discontinuous clay films within the lamellae.
TYPE LOCATION: Los Alamos County, New Mexico. Unsectionized; state plane coordinates N. 1,747,900 feet and E. 488,300 feet. RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is moist in some part during the 120 days following the winter solstice and is moist in all parts less than 25 percent of the time that the soil temperature at 20 inch depths is above 41 degrees F.
Soil temperature - 52 to 54 degrees F.
Depth to the base of the Bt horizon - 10 to 20 inches
Depth to contrasting particle-size: 15 to 30 inches
A horizon - Value: 4 or 5 dry, 3 or 4 moist Chroma: 2 or 3
Bt horizon - Value: 4 through 6 dry, 3 or 4 moist Chroma: 4 or 6 Reaction: Neutral or mildly alkaline Rock fragments: 35 to 60 percent pumice pebbles
2C horizon - Reaction: Neutral or mildly alkaline Rock fragments: 60 to 75 percent pumice pebbles
3C horizon - Value: (lamella) 6 or 7 dry, 5 or 6 moist Chroma: (lamella) 6 or 8 moist
COMPETING SERIES: There are no other series in this family; similar soils in other families are the Espiritu, Fragua and Guaje series. All these soils lack contrasting particle-size. In addition Fragua soils have less than 35 percent rock fragments and Guaje soils lack argillic horizons.
GEOGRAPHIC SETTING: Frijoles soils are on mesas with slopes of 1 to 8 percent.
The soil formed in alluvium with an eolian influence derived from pumice. The elevation is 6,000 to 8,000 feet. Mean annual precipitation is about 12 to 14 inches. The mean annual temperature is about 50 to 52 degrees F., and the frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is Nyjack which has less than 35 percent rock fragments.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability in the upper part and very rapid below.
USE AND VEGETATION: These soils are used mostly for grazing. Native vegetation is blue grama, oneseed juniper, and pinyon.
DISTRIBUTION AND EXTENT: Northcentral New Mexico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Sandoval County Area, Los Alamos County, New Mexico, 1979.
REMARKS: The classification has been changed from loamy-skeletal, mixed, mesic Aridic Haplustalfs. A better classification would be loamy-skeletal over cindery, but this particle size class is not currently recognized.
DIAGNOSTIC HORIZONS AND FEATURES RECOGNIZED IN THIS PEDON ARE:
Ochric epipedon - The zone from the surface to a depth of about 3 inches. (A horizon)
Argillic horizon - The zone from about 3 to 13 inches. (Bt1, Bt2 horizons)
Contrasting layer - The boundary at about 20 inches. (3C horizon)