LOCATION LAPDUN NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, mesic Aridic Calciustolls
TYPICAL PEDON: Lapdun gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 9 inches; brown (10YR 4/3) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, friable, slightly sticky and plastic; many fine and very fine roots; 30 percent gravel; violently effervescent; about 55 percent calcium carbonate; moderately alkaline; clear smooth boundary. (8 to 12 inches thick)
Bk1--9 to 19 inches; very pale brown (10YR 8/3) very gravelly clay loam, very pale brown (10YR 7/3) moist; massive, extremely hard, extremely firm, sticky, plastic; many very fine roots; 50 percent gravel; violently effervescent, about 55 percent calcium carbonate; moderately alkaline; gradual wavy boundary. (9 to 16 inches thick)
Bk2--19 to 35 inches; very pale brown (10YR 8/2) extremely gravelly clay loam, very pale brown (10YR 8/3) moist; massive; extremely hard, extremely firm, sticky, plastic; common very fine roots; about 90 percent gravel; strongly effervescent; about 55 percent calcium carbonate; strongly alkaline; clear wavy boundary. (14 to 25 inches thick)
Bk3--35 to 60 inches; pink (7.5YR 7/4) very gravelly clay loam, reddish yellow (7.5YR 7/6) moist; massive; extremely hard, extremely firm, sticky, plastic; few fine roots; about 40 percent gravel, violently effervescent; about 60 percent calcium carbonate decreasing to about 15 percent in the lower part of the horizon; strongly alkaline.
TYPE LOCATION: Socorro County, New Mexico; approximately 7.5 miles south and 10.5 miles west of Magdalena, 250 feet east and 300 feet south of the NW corner of sec. 32, T. 3 S., R. 5 W.
RANGE IN CHARACTERISTICS:
Gravel and cobble content: 30 to 90 percent and varies greatly between horizons
Calcium carbonate content: 50 to 60 percent. Fragments of petrocalcic material are common in the A or Bk horizons.
Soil moisture: Aridic ustic moisture regime.
A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 through 3
Texture: gravelly loam, very gravelly loam or very cobbly loam
Calcium carbonate content: 10 to 55 percent
Rock fragments: 20 to 40 percent.
Bk horizons
Hue: 7.5YR or 10YR
Value: 5 through 8 dry, 4 through 8 moist
Chroma: 2 through 6
Texture: very gravelly clay loam, extremely gravelly clay loam, or very gravelly loam, very cobbly loam with lenses of gravelly sandy loam very cobbly loamy sand. Some pedons have coarser textures with cobbles below the control section. Calcium carbonate equivalent: decreases to about 15 percent in the lower Bk horizon.
COMPETING SERIES: These are the Cuate (NM) and Mackscanyon (NV) series. Cuate soils have a lithic contact at 20 to 40 inches. Mackscanyon soils formed in alluvium from limestone and dolostone and have silica pendants on bottom of rock fragments.
GEOGRAPHIC SETTING: Lapdun soils are at elevations of 6,500 to 7,700 feet on broad nearly level to moderately steep alluvial fans. Slopes range from 0 to 30 percent. The soils formed in sediments derived mainly from rhyolites, andesites, and latites. Average annual precipitation ranges from about 11 to 15 inches, the average annual air temperature ranges from about 47 to 56 degrees F. The frost-free season is about 115 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Cerrillos, Clovis, Millett, Penistaja, and Sedillo series. Cerrillos, Clovis, Millett, Penistaja, and Sedillo soils lack a mollic epipedon and have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for livestock grazing and wildlife. Vegetation is mainly bluegrass, black grama, broom snakeweed, and threeawn.
DISTRIBUTION AND EXTENT: Southcentral New Mexico. The series is of moderate extent. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Socorro County, New Mexico, 1984.