LOCATION THAAD NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Pachic Argiustolls
TYPICAL PEDON: Thaad extremely gravelly loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; reddish brown (5YR 4/3) crushed, extremely gravelly loam, dark reddish brown (5YR 2.5/2) crushed, moist; 16 percent clay; weak fine granular structure; loose; nonsticky and nonplastic; common fine roots throughout; 65 percent nonflat subrounded 0.1- to 3-inch tuff gravel; noneffervescent by HCl, 1 normal; strongly acid, pH 5.1, pH meter 1:1 water; gradual smooth boundary. (0 to 7 inches thick)
A2--5 to 12 inches; dark reddish gray (5YR 4/2) crushed, very gravelly loam, black (5YR 2.5/1) crushed, moist; 18 percent clay; weak medium subangular blocky and weak fine subangular blocky structure; slightly hard, friable; slightly sticky and slightly plastic; many fine roots throughout; common fine dendritic tubular pores; 50 percent nonflat subrounded 0.1- to 3-inch tuff gravel and 5 percent nonflat subrounded 3- to 10-inch tuff cobbles; noneffervescent by HCl, 1 normal; very strongly acid, pH 4.9, pH meter 1:1 water; gradual smooth boundary. (4 to 11 inches thick)
Bt1--12 to 21 inches; reddish brown (5YR 4/3) crushed, extremely gravelly loam, dark reddish brown (5YR 3/2) crushed, moist; 24 percent clay; moderate medium subangular blocky structure; moderately, hard firm; slightly sticky and slightly plastic; common fine roots throughout; few fine dendritic tubular pores; 10 percent patchy faint clay films on faces of peds; 50 percent nonflat subrounded 0.1- to 3-inch tuff gravel, 10 percent nonflat subrounded 3- to 10-inch tuff cobbles; noneffervescent by HCl, 1 normal; strongly acid, pH 5.1, pH meter 1:1 water; clear smooth boundary. (6 to 12 inches thick)
Bt2--21 to 32 inches; reddish brown (5YR 4/4) crushed, extremely gravelly clay loam, dark reddish brown (5YR 3/4) crushed, moist; 28 percent clay; moderate fine subangular blocky structure; moderately hard, firm; moderately sticky and moderately plastic; few fine roots throughout; few fine dendritic tubular pores; 5 percent patchy faint clay films on faces of peds; 70 percent nonflat subrounded 0.1- to 3-inch tuff gravel, 10 percent nonflat subrounded 3- to 10-inch tuff cobbles; noneffervescent by HCl, 1 normal; strongly acid, pH 5.1, pH meter 1:1 water; clear smooth boundary. (8 to 15 inches thick)
Bt3--32 to 44 inches; reddish brown (5YR 4/4) crushed, extremely gravelly clay loam, dark reddish brown (5YR 3/4) crushed, moist; 29 percent clay; moderate fine subangular blocky structure; moderately hard, firm; moderately sticky and moderately plastic, few fine roots throughout; very few fine dendritic tubular pores; 5 percent patchy faint clay films on faces of peds; 55 percent nonflat subrounded 0.1- to 3-inch tuff gravel and 10 percent nonflat subrounded 3- to 10-inch tuff cobbles; noneffervescent by HCl, 1 normal; strongly acid, pH 5.2, pH meter 1:1 water. (combined thickness of the Bt horizons range from 22 to 32 inches)
R--44 inches; thickly bedded massive tuff
TYPE LOCATION: Dona Ana County, New Mexico; approximately 4.4 miles west and 5.1 miles south of White Sands, 1,210 feet west and 290 feet south of the northeast corner of sec. 20, T. 23 S., R. 4 E. USGS Organ Peak topographic quadrangle; latitude. 32 degrees, 17 minutes, 59 seconds north and longitude 106 degrees 33 minutes 05 seconds west. UTM zone 13S, 354050E, 3574490N; NAD 27.
RANGE IN CHARACTERISTICS:
Soil Moisture: The moisture control section is usually dry in some or in all parts for six-tenths or more of the time that the soil temperature exceeds 41 degrees F. Some part of the epipedon is moist for more than 90 cumulative days in most years when the soil temperature exceeds 41 degrees F. Aridic ustic moisture regime.
Mean annual soil temperature - 55 to 59 degrees F.
Depth to lithic contact - 40 to 60 inches
Depth to argillic horizon - 10 to 18 inches
Thickness of mollic epipedon - 20 to 30 inches
Particle-size control section (weighted average)-
Clay content: 18 to 35 percent
Coarse fragment content: 60 to 85 percent
Reaction: very strongly acid to strongly acid
A horizon:
Hue: 5YR or 7.5YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 1 to 3, dry or moist
Coarse fragments: tuff fragments; 50 to 75 percent coarse fragments:; 50 to 65 percent gravel, 0 to 10 percent cobbles.
Bt horizons:
Hue: 5YR or 7.5YR
Value: 4 or 5 dry, 2 to 4 moist
Chroma: 2 to 4, dry or moist
Texture modifier: very gravelly or extremely gravelly
Coarse fragments: tuff fragments; 55 to 85 percent total coarse fragments; 45 to 70 percent gravel; 10 to 15 percent cobbles.
Texture: loam or clay loam
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material: Colluvium from tuff
Landform: Mountain flanks and bases
Slope: 15 to 35 percent
Mean annual temperature: 54 to 57 degrees F
Mean annual precipitation: 14 to 16 inches
Precipitation pattern: Precipitation falls mostly during the months of July through September. The driest months are March and April. Precipitation during the months of January, February, and March is less than 13 percent of the total.
Frost-free period: 130 to 170 days
Elevation: 5,800 to 6,800 feet
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Arbol,
Rotagilla, and
Poblano series.
Arbol and Rotagilla soils are shallow and very shallow and are on mountain tops and flanks.
Poblano soils have a clayey-skeletal control section and are on mountain flanks and bases.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is high on slopes of 15 to 20 percent and very high on slopes greater than 20 percent.
USE AND VEGETATION: Used for livestock grazing. Vegetation is of the pinyon-juniper-oak savannah type consisting of sideoats grama, hairy grama, muhly spp., pinyon pine, oak spp., alligator juniper, and mountain mahogany.
DISTRIBUTION AND EXTENT: Southern New Mexico; LRR D, MLRA 42. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Dona Ana County, New Mexico; 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle size control section: The zone between 12 and 32 inches. (Bt1, Bt2, and Bt3)
Mollic epipedon: The zone from 0 to 21 inches (A1, A2, and Bt1 horizons).
Argillic horizon: The zone from 12 to 44 inches (Bt1, Bt2, and Bt3 horizons).
Aridic feature: An ustic moisture regime that borders on the aridic moisture regime.
The assignment of the cation exchange capacity is inferred from lab data from similar soils in the surrounding area.
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.